Ophthalmology Review

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May 30, 2006

Laser in situ keratomileusis: Ablation on the flap and stromal bed in a primary treatment

JCRS Pages 590-594 (April 2006)
Purpose
To analyze outcomes of laser in situ keratomileusis (LASIK) performed on the flap and on the stromal bed at the same time in a primary treatment.
Twenty-two cases were studied retrospectively; the mean age of the patients was 33.15 years . Inclusion criteria were low pachymetry or topographic asymmetry,presented with topographic asymmetry (inferior–superior difference more than 1.5 diopters [D]). Ablation was performed on the flap from the back and on the bed. The flap was made using the Technolas Hansatome microkeratome and the ablation by the Technolas 217z excimer laser (both by Bausch & Lomb). Preop SE was −5.61 D, the cylinder was −1.78 D, and the BSCVA was 0.77 . Difficulties and complications of the technique, efficacy and safety index, and aberrations were analyzed.

Results
According to the surgical plan and our nomogram, diopters corrected on the flap were −1.73 and on the bed were −4.77 . The mean follow-up was 8.28 months. At 6 months, the SE was −0.21 , vectorial change was 1.69 , and the BSCVA was 0.77. Postop,no eye had an increase in refractive astigmatism. UCVA was 20/40 or better in all cases (100%) and 20/25 or better in 13 cases (59.1%). Regarding gained and lost lines of BSCVA, 54.5% conserved the lines, 18.2% lost 1 line, 9.1% gained 1 line, and 18.2% gained 2 lines.

Conclusions
Simultaneous ablation on the flap and on the bed in cases of low pachymetry or topographical asymmetry was predictable, effective, and safe.

Posted by alireza habibollahi at 11:24 PM | Comments (0)

To determine the correlation between patient perception and clinical measurements after wavefront-guided LASIK.

JCRS Pages 577-583 (April 2006)

In 274 myopic-astigmatic eyes,wavefront-guided LASIK procedures were at 6 sites. Comprehensive evaluations of vision and ocular health were conducted preoperatively and for 6 months postoperatively. Visual acuity and contrast sensitivity were measured, and questionnaires were administered. Questionnaire responses were compared with clinical measurements.

Results
The overall distribution shifted toward “more satisfied.” The “very satisfied” population increased by as much as 70% in all areas. There was no significant change in frequency of visual symptoms. Patients were more expressive about visual decline than visual improvement. Perception of changes in vision appeared to be related to mesopic contrast sensitivity and mesopic contrast sensitivity under glare. Mesopic pupil diameter was not a major predictor of patient satisfaction. Contact lens wearers were more satisfied with postoperative vision than were spectacle wearers. Men were more likely to report visual symptoms and to complain about night vision, although their changes were the same as those of the women. Residual refractive error was a major predictor for most questionnaire items.

Conclusion
Most patients were as satisfied or more satisfied with their postoperative uncorrected visual acuity than with their preoperative best corrected visual acuity. By continuing to minimize postoperative refractive error through the use of nomograms and improved technology, visual complaints such as night glare and halo could be diminished or even eliminated. The study shows that subjective experience affected satisfaction with results. Some dissatisfaction might be mitigated by being sure patients are educated and have realistic expectations before surgery.

Posted by alireza habibollahi at 11:15 PM | Comments (0)

Surgically induced astigmatism after phacoemulsification in eyes with mild to moderate corneal astigmatism: Temporal versus on-axis clear corneal incisions

JCRS Pages 565-572 (April 2006)
To determine whether there is a difference in surgically induced astigmatism (SIA) and post-op UCVA and BCVA between 2 types of clear corneal incisions used in phacoemulsification: the temporal and the on-axis (ie, on the steeper corneal meridian) clear corneal incision (CCTI and CCOI, respectively).
In a prospective randomized controlled trial (pilot study), 61 eyes with cataract and mild to moderate corneal astigmatism (<2.58 diopters [D] on corneal topography) having phacoemulsification (single surgeon, 3.2 mm incision) were randomized to receive CCTI or CCOI. Main outcome measures included postoperative BCVA and corneal astigmatism and SIA (calculated using the Holladay vector analysis formula). Measurements were repeated postoperatively at 3 weeks in all eyes, whereas only 46 eyes made it to the final assessment at 8 weeks. Continuous variables between groups were compared by Student t test. The power of the study was calculated.

Results
At the first follow-up, the difference in SIA between the 2 incision types was 0.15 D and it was not statistically significant (0.65 D in CCOI; 0.50 D in CCTI). At the second follow-up, the difference was 0.29 D and it was statistically significant (0.63 D in CCOI; 0.34 D in CCTI; P = .0004). There was no statistically significant difference in the final postoperative visual acuity. The power of the pilot study was 72%.

Conclusion
Seven weeks after small-incision phacoemulsification, the CCTI induced less SIA than the CCOI; however, there were no significant differences in the final UCVA and BCVA.

Posted by alireza habibollahi at 11:08 PM | Comments (0)

Technique for measuring LASIK flap thickness using the IntraLase laser

JCRS April 2006

Measurement of LASIK flap thickness is required to estimate residual bed thickness. Historically, flap thickness has been assumed, estimated based on microkeratome head labeling, guessed based on flap handling characteristics, or calculated by subtraction pachymetry. We describe a method for measuring flap thickness before actual flap elevation using the IntraLase laser.

Posted by alireza habibollahi at 11:04 PM | Comments (0)

May 28, 2006

Pentacam Vs Ultrasound in corneal thickness measurment

Review Of Ophthalmology May 2006

In an independent study, re­searchers from Montreal and Paris say the Oculus Pentacam produces very accurate corneal thickness measurements when compared to ultrasonic pachymetry.The clinicians tested both eyes of 22 normal subjects. At one visit, an observer acquired three Pentacam elevation maps, then measured cor­neal thickness in nine different locations with ultrasonic pachymetry: central; superior; nasal-superior; nasal; nasal-inferior; inferior; temporal-inferior; temporal; and temporal-superior. They obtained three successive ultrasonic measurements in each location. At another visit, within one to six weeks of the first, two ob­servers acquired three more Penta­cam maps. The order of the visits, observers and eyes were all randomized.The researchers say that repeatability of the three successive measurements performed during the same visit ranged from substantial to almost perfect. The average intraclass correlation coefficient values, which measure the reliability/reproducibility of a measurement (with a value of 1 being perfect), were 0.94 for right eyes and 0.948 for left eyes. The lowest ICCs were obtained for the superior location measurements.Compared to ul­tra­­sound’s “true” values, the clinicians say the Penta­cam’s accuracy was almost perfect for all locations. ICCs ranged from 0.863 to 0.993 with an average of 0.933 for OD and from 0.891 to 0.988 with an average of 0.936 for OS. Cen­tral pachymetries yielded the highest values.Researchers say that accuracy at this level means the Pentacam could be used in place of ultrasonic pachy­metry

Posted by mehdi khanlari at 11:40 PM | Comments (0)

Acoustic Factor and Orbscan

Review Of Ophthalmologhy May 2006

Researchers from Glasgow Cale­donian University say that, though Bausch & Lomb Orbscan’s acoustic correction factor is helpful in determining central cor­neal thickness, clinicians shouldn’t blindly rely on it when assessing more peripheral corneal locations.In an independent study, the in­vestigators performed corneal pachy­metry on 50 eyes of 25 healthy subjects. They extracted Orbscan II data at the geometric center, two mid-peripheral locations 2.5 mm to either side of the center, and peripheral locations 4.5 mm from the center along the horizontal meridian. They also obtained ultrasound readings from the same locations as Orbscan, after instillation of a drop of topical anesthetic. They took three readings at each location and averaged the measurements for each cornea.The differences between the two modalities were statistically significant at all corneal locations, and the re­searchers add that the customary acoustic correction factor of 0.92 didn’t correct them. Because of this, the researchers recommend using great caution when interpreting Orb­scan depth measurements, especially in areas farther away from the cor­neal center.1326

Posted by mehdi khanlari at 11:36 PM | Comments (0)

Uveitis after IOL removal

Review of Ophthalmology May 2006

Foldable acrylic IOLs, despite excellent safety, sometimes require removal. Following two cases of unexpectedly protracted post lens-removal uveitis, researchers at the Texas Health Science Center, San Antonio, sought a physical or chemical basis for such chronic inflammation associated with a brief intraocular exposure to a transected acrylic lens.They tested four commercially available acrylate-meth­ac­ry­late copolymer lenses. Lenses were cut with a surgical scissors to check for ejection of physical debris. Chemical analysis of the supernatant was carried out to determine if potentially irritating substances were liberated. Lens fragments were soaked in a variety of solvents and deionized water (DIW). Nuclear magnetic resonance spectroscopy con­firmed the structures of liberated chemical compounds.Videomicroscopy demonstrated that no solid lens fragments were re­leased during cutting. In both meth­ylene chloride solvent and DIW, bis-2-ethylhexyl phthalate was identified with gas chromatography, and the structure confirmed with NMR. Phthalates are chemical compounds that are added to plastics to increase their flexibility. The concentration of phthalate eluted into ionized water (~35 µg/ml) was comparable to that liberated by methylene chloride (~50 µg/ml). They exposed cultured hu­man lens epithelial cells to the identified phthalate to evaluate cell viability. The results indicated cell viability was reduced at phthalate concentrations as low as 20 µg/ml. As a result, the group recommends that if replacement of a defective lens becomes necessary, bisection of the lens in situ should be avoided, as a bi­sected IOL may release phthalates into the eye. Because bis-2-ethylhexyl phthalate was isolated in DIW, it could be released into the aqueous and affect in­traocular tissues. The emerging aware­ness of the toxicity of low-level phthalates in a variety of biological settings warrants further studies of the interaction of plasticizers with intraocular tissue.608

Posted by mehdi khanlari at 11:24 PM | Comments (0)

LRI and HOA

Review of Ophthalmology May 2006

Limbal relaxing incisions do correct astigmatism after cataract surgery, but at the price of significantly increased HOAs, say researchers at the University of Tsukuba, Japan. In the study, 18 eyes of 18 patients (mean age, 75.3 ±7.2 years, range, 60 to 87) underwent cataract surgery and IOL implantation. The patients had astigmatism of 2 D or more, and logMAR uncorrected VA was 0.10 or worse. A single surgeon made a 550-µm depth incision with a diamond knife along the corneal limbus in the steepest meridian. Un­cor­rected and best corrected visual acuity, mean spherical equivalent, cylindrical refraction, and wavefront ab­erration were examined before and one month after surgery.By LRI, logMAR UCVA improved from 0.388 to 0.079 (p<0.0001). LogMAR BCVA changed from -0.041 to -0.071. MSE showed a hyperopic shift from -0.43 ±0.62 D to 0.04 ±0.64 D (p=0.0019). Refractive astigmatism was reduced from -2.90 ±1.20 D to -0.90 ±0.92 D (p<0.0001). Third- (p=0.0093), fourth- (p<0.0001), and total HOA (p=0.0030) of the cornea significantly increased. Ocular fourth-order (p=0.0038) and total HOA (p=0.0498) significantly increased by LRI.575

Posted by mehdi khanlari at 11:21 PM | Comments (0)

Restore and Monofocal IOL and HOA

Ophthlmology Times May 2006

Compared to a monofocal IOL, the ReSTOR apodized diffractive IOL (Al­con) appears to generate lower levels of HOAs, according to independent re­search in Milan, Italy. ReSTOR lenses were implanted in 23 eyes in routine cataract surgery. In 10 myopes, the mean preop spherical equivalent refraction was -2.3 D ±1.4 D, and in 13 hy­per­opes, the mean preop SE was +1.8 D ±1.0 D. Axial length (AL) was measured with the IOL Master, and keratometry values by corneal topography. When using the apodized lens it’s essential that visual axis, pupillary center and IOL center be matched. Accordingly, after un­complicated procedures, IOL centration in the bag was followed by the in­jection of a miotic and subsequent alignment of the IOL rings with the 3 to 4 mm miotic pupil.Three months after surgery, mean SE was -0.45 D ±0.6 D for the myopes, and -0.02 D ±0.2 D for the hyperopes. All eyes were able to read J3 without correction. In a typical eye, total HOA was 0.288 µm, coma was 0.070 µm and SE was 0.042 µm. In contrast, total HOA after the implantation of a mo­no­­focal IOL (AcrySof) in comparable eyes were registered at 0.631 µm, coma at 0.118 µm and spherical aberration at 0.073 µm. There were no complaints of postoperative glare, halos or ghosting in the eyes with the apodized IOL. In this small group of eyes, the group adds, the ReSTOR produced no subjective visual problems.

Posted by mehdi khanlari at 11:17 PM | Comments (0)

LASIK Bioptics

CRS Today May 2006
The concept of bioptics was first described by Roberto Zaldivar, MD,1 when he performed LASIK to correct residual refractive error in eyes that had received phakic IOLs. Dr. Zaldivar found that the bioptics procedure was an effective and predictable method for correcting residual error in patients who had extreme preoperative myopia of up to -35.00D. In 1994, José Güell, MD, described his concept of adjustable refractive surgery2; he performed LASIK to correct residual ametropia after different types of intraocular surgeries, including implantation surgeries for IOLs and phakic IOLs, penetrating keratoplasties, and corneal refractive surgeries such as PRK and radial and arcuate keratotomy.3 Currently, ophthalmologists use the term bioptics when techniques for IOL implantation are followed by a procedure involving excimer laser corneal ablation such as LASIK, Epi-LASIK, or PRK.4-9 The advantage of placing the IOL first is the improvement in the patient's quality of vision. Using corneal refractive surgical techniques, such as LASIK, as a secondary enhancement tool improves the accuracy of the final refractive outcome.
Potential candidates for a planned bioptics procedure include patients who wish to minimize their dependence on corrective eyewear after lens surgery. If a patient desires a presbyopia-correcting IOL and has more than 0.75D of residual postoperative astigmatism with a healthy cornea, he may be a good candidate for a planned bioptics procedure. Most available excimer lasers can effectively treat up to 5.00D of astigmatism. For higher levels, the surgeon may use a combination of limbal relaxing incisions with bioptics to effectively fine-tune the refractive outcome.
Timing of Flap Creation
One of the biggest questions when performing a planned LASIK bioptics procedure is when to create the LASIK flap. One may cut the flap 1 to 2 weeks in advance or at the time of the intraocular surgery.2,3 Cutting the flap prior to placing the IOL avoids the possible risks related to a microkeratome use in eyes that contain an IOL. The major potential risk of using a microkeratome in an eye with an IOL is corneal endothelial damage.
Creating the flap before the intraocular procedure allows the earlier correction of residual ametropia (4 to 6 weeks after the intraocular surgery). The surgeon can simply lift the LASIK flap instead of risking potential complications due to the increased IOP secondary to placing a microkeratome suction ring on these eyes. A potential disadvantage of creating the flap before the intraocular procedure is the increased risk of epithelial ingrowth after lifting the flap for the enhancement procedure.
Another technique is to perform the bioptics procedure in a sequential fashion. After the IOL surgery, the eye is allowed to heal, and the refraction is permitted to stabilize for at least 3 months prior to the LASIK enhancement.1,4-6 The advantage of this approach is that it avoids having to lift the flap on the eye, thus minimizing the incidence of epithelial ingrowth and other potential flap-related complications, such as diffuse lamellar keratitis, for these patients. There is a difference between cutting a new flap after the intraocular procedure and lifting a previously created flap in terms of the risk of epithelial ingrowth. This risk is higher with a relifted versus freshly cut flap. This sequential method is the only option for patients awaiting advanced surface ablation.

Posted by aman at 11:08 PM | Comments (0)

Carrots and Glaucoma

Review of ophthalmology may 2006

.....Carrots appear to decrease glaucoma in Caucasians and African Amer­icans. A random sample of optic nerve photographs and visual fields of 1,274 older, ambulatory women who participated in the Study of Osteoporotic Fractures were graded for glaucoma by three specialists. Consumption of fruits and vegetables was assessed by responses to Block Food Frequency Questionnaires. The relationship be­tween food consumption and glaucoma was evaluated after adjusting for potential confound­ers such as study site, age, race, smoking and the presence of diabetes; an­aly­sis was performed for the group as a whole and for Caucasian and Afri­can-American women separatelyWomen who reported eating more than two carrots per week were less likely to have glaucoma than those who ate less than one (p=0.003). This was true for both Cau­casians (p=0.014) and African Ameri­cans (p=0.044). Also, eating one or more servings of green collards/kale per month was protective (p=0.009) compared to eating less than one, especially among African-American women (p=0.001), and there was a pro­tective trend in African-American women who ate more fresh oranges (p=0.006), more fresh peaches (p=0.021), and more spinach (p=0.013).3449

Posted by mehdi khanlari at 11:01 PM | Comments (0)

Multifocal lenses and children

ophthalmology times may 1 2006

....The FDA has approved three multifocal IOLs for use in adults, and many doctors are eager to know if they can be used in children."My caution is that these multifocal lenses are based on the simultaneous vision concept where two or more images are formed on the retina, and the brain must select the image it wants to see," Dr. Wilson said. "Some loss of contrast is inherent with this, but I am worried about uncorrected refractive error. In patients who have hyperopia, myopia, or astigmatism greater than 1 D, uncorrected refractive error with two blurred images, neither one of which is in focus, might be worse (especially when the child becomes myopic with growth) than uncorrected refractive error when the glasses are not being worn with a monofocal implant. "Ironically, for the non-compliant child, we may be making amblyopia worse by implanting a multifocal IOL," Dr. Wilson added.The new generation of multifocal IOLs will probably be tested first in teenagers, he said, and he urged ophthalmologists to be cautious about implanting them in younger children whose eyes are still growing or could be amblyopic. Dr. Wilson discussed lens implants during the Pediatric Ophthalmology Subspecialty Day at the American Academy of Ophthalmology meeting

Posted by mehdi khanlari at 10:51 PM | Comments (0)

Where Is the Axis?

CRS Today May 2006
The surgical correction of astigmatism.
Bruce Wallace III, MD, FACS
Central corneal surgery such as PRK, Epi-LASIK, and LASIK can reduce unwanted postoperative astigmatism, but these procedures are relatively expensive alternatives to incisional, peripheral, corneal surgery such as limbal relaxing incisions (LRIs). Excimer laser ablation also means another surgical event for patients, and some of these patients may have other ocular conditions such as dry eye, which might adversely affect their postoperative outcome. Most surgeons have found that LRIs provide a safe and effective means of correcting unwanted cylinder with remarkable postoperative stability. For these reasons, LRIs have become a popular method to reduce astigmatism.
Astigmatic procedures require the surgeon to select the proper axis of astigmatism. With toric IOLs and LRIs, the plus axis is the reference point. With corneal laser correction, the minus axis is the reference point.
AXIS LOCATION STUDY
My colleagues and I performed a study to decipher the best way to locate the proper axis for astigmatic correction.1 We found a surprising variance between refractive, keratometric, and corneal topographic axis locations among patients with 2.00D or less of measurable cylinder. However, for eyes with more than 2.50D, we began to see a stronger correlation of the axis' location with all methods used to measure corneal cylinder.
Most of my patients in need of astigmatic correction benefit from LRIs. When planning the incisions, I pay most attention to the axis' location and cylindrical pattern as displayed by the corneal topographic map. If I find a significant disparity between corneal topography and keratometry (ie, more than 30°), I may elect to postpone the LRI until after the lens' replacement and usually will offer any needed astigmatic correction for this eye in tandem with lens surgery on the fellow eye.

Posted by aman at 10:51 PM | Comments (0)

The Modified CTR

CRS Today May 2006
Robert J. Cionni, MD
The Modified Capsular Tension Ring (CTR) (Morcher GmbH, Stuttgart, Germany; distributed in the US by FCI Ophthalmics, Inc., Marshfield Hills, MA) is much like a standard CTR except for the fixation hook attached to the PMMA ring filament. As the device lies inside the capsular bag, this hook rests at a plane anterior to that of the ring so that the hook courses around the capsulorhexis' edge. Passing a suture through an eyelet located at the edge of the fixation hook fixes the ring to the scleral wall. The Modified CTR is indicated when a standard CTR will not provide sufficient stability to allow phacoemulsification and/or the long-term stability and centration of an IOL implant in the bag. Specifically, the device is appropriate in eyes with more than 180¼ of zonular dialysis and in cases of marked lens decentration (eg, from trauma or Marfan's syndrome). My advice for success with the Modified CTR follows.
INSERTING THE RING
After nuclear removal, I like to create a space for the Modified CTR by viscodissecting all of the cortex away from the periphery of the capsular bag. I prefer a dispersive viscoelastic for this maneuver, because some of the agent can ooze from the incision versus the expulsion of a cohesive glob. Before I place the ring in the bag, I preload the fixation hook's eyelet with a suture. I would recommend 9–0 Prolene .
The Modified CTR is available in three versions. Model 1-L (Figure 1) must be inserted manually, so I use a tying forceps to feed the device into the bag so that the part closest to the fixation hook goes in last. During the insertion of the ring, the fixation hook should catch naturally anterior to the capsulorhexis' edge. If not, the surgeon must manipulate it anteriorly.
The model 2-C is a mirror image of the 1-L, so it may be inserted with an injector .
The 2-L model has two fixation hooks and is indicated for extremely loose lenses. This is the most difficult version of the Modified CTR to use. I would recommend that surgeons first become familiar with suturing a one-hook model in a few less difficult cases before attempting to use the 2-L.
CONCLUSION
The availability of the CTR and now the Modified CTR has greatly enhanced cataract surgeons' ability to manage challenging cases. Videos demonstrating the use of the Modified CTR may be found at the AAO's Web site as well as at http://www.fci-ophthalmics.com/videos/cionni_ctr_video.htm.

Posted by aman at 10:38 PM | Comments (0)

Dr. Schepens, 'father of modern retinal surgery,' dies

Ophthalmology Times May 1, 2006

The late Charles L. Schepens, MD, was well-known by ophthalmologists worldwide as the father of modern retinal surgery after having discovered a way to re-attach retinas and restore vision to nearly 90% of patients, and having invented the binocular indirect ophthalmoscope.Dr. Schepens died March 28. He was 94.As founder of the Schepens Eye Research Institute and the Schepens Retina Associates Foundation in Boston, Dr. Schepens was a clinical professor of ophthalmology, emeritus, at Harvard Medical School. He was named one of three laureates by the American Academy of Ophthalmology in 2003. In 1999, he was voted one of the 10 most influential ophthalmologists of the 20th century by the American Society of Cataract and Refractive Surgery.Dr. Schepens was born in Mouscron, Belgium, the son of a general practitioner. He was in postdoctoral training and a captain in the Belgian Air Force medical corps at the start of World War II. After twice being arrested by the Gestapo for helping to smuggle documents and maps out of Belgium, he fled with his family to France and assumed the name Jacques Perot. Beneath the cover of the working lumber mill, he helped workers escape over the Pyrenees Mountains into Spain until the Gestapo learned of the mill's real purpose. Dr. Schepens fled to London, where he was joined 9 months later by his wife and children.It was in London, in 1945, that he developed the binocular indirect ophthalmoscope, a stereoscopic viewing system and light source that allowed him to examine the entire retina, including the periphery, in three dimensions. According to the Smithsonian Institution, which has a prototype in its collection, he built the instrument with bits of metal he gathered on the streets of London during the German blitz.Dr. Schepens immigrated to the United States in 1947 to pursue eye research at the Howe Laboratory of Ophthalmology at Harvard Medical School, and he formed the retina service—the first of its kind—at the Massachusetts Eye & Ear Infirmary 2 years later.In 1950, he founded the Retina Foundation, which focused on re-attaching detached retinas and related conditions. The Retina Foundation evolved into the Schepens Eye Research Institute—which became the largest independent eye research facility in the nation—and the Schepens Retina Associates Foundation, which is dedicated to clinical eye research, teaching, and patient care.

Posted by mehdi khanlari at 10:32 PM | Comments (0)

All dose groups of siRNA show positive change in visual acuity

Ophthalmology Times May 1, 2006

Baltimore—Intravitreal injection of a small interfering RNA molecule (Sirna-027, Sirna Therapeutics Inc.) appears to be safe and well tolerated by patients for treatment of choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD), according to Edward J. Quinlan, MD, who reported the preliminary data from the phase I clinical trial. "This trial involves a novel pharmacologic agent known as a small interfering RNA (siRNA) molecule," said Dr. Quinlan, assistant professor of ophthalmology, Johns Hopkins University School of Medicine, Wilmer Eye Institute, Baltimore. "RNA interference is a recently discovered process for silencing gene expression."It has been shown that when double-stranded RNA enters a cell, an enzyme known as DICER cleaves it into smaller fragments that can combine with proteins to form a complex called RISC, or the RNA-induced silencing complex,"RISC, in turn, uses small RNA fragments to look for complementary sequences on messenger RNA to bind to and degrade."This silences the expression of the gene. The short RNA fragments have become known as siRNAs," said Dr. Quinlan, The siRNAs are highly versatile and can be designed to target any gene. In this case, Sirna-027 is designed to target vascular endothelial growth factor receptor 1 (VEGFR1) mRNA. Dr. Quinlan explained that Sirna-027 has been "chemically optimized" to enhance its stability, which is in contrast to most siRNAs, which have a short half life.

Posted by mehdi khanlari at 10:22 PM | Comments (0)

Intrastromal corneal ring helps prevent graft rejection, study says

OCULAR SURGERY NEWS EUROPE/ASIA-PACIFIC EDITION June 2006
The implantation of an intrastromal corneal ring in patients undergoing corneal transplant may reduce immune reaction, according to the developer of the device.
“We made and implanted these rings for years to reduce astigmatism, stabilize the wound and improve healing,” said Jörg H. Krumeich, MD, referring to intrastromal corneal rings (ISCR) of his own design, also known as Krumeich rings.
The Krumeich ISCR is made from an alloy of 69% cobalt, 24% steel, 4.5% molybdenum and 2% titanium, according to Dr. Krumeich. It is produced and distributed by HumanOptics. The ring preferably should be used with the guided trephine system or the Hanna trephine, he said.
Barrier to immune reaction
In a study, 179 consecutive cases of penetrating keratoplasty with ISCR implants were compared with 101 eyes that had undergone the same procedure without the ring. The follow-up in all eyes was at least 4 years.
In the eyes where the ring was implanted, the immune rejection rate was significantly lower (two cases out of 179, 1.2%) than in the control group (six cases out of 101, 6%). We also observed that the immune reaction in the eyes with the ring occurred within a few months after the operation, while the immune reaction without the ring had a tendency to occur also much later, up to 2 years postoperatively,” Dr. Krumeich said. He noted that 60% of the rejection cases with the ring could be resolved with the appropriate immunosuppressant therapy whereas only 14% of the rejection cases without the ring could be treated successfully.
New vessel growth
Two consecutive transplants without success, then a third transplant with the ring that works perfectly well and is still clear after 4 years,” Dr. Krumeich said.
In addition, the ring also appears to have inhibitory effects on vascular growth. Once the ISCR is implanted, superficial vessel growth may occur, but it almost invariably stops outside the ring and only in rare cases crosses over.

Posted by aman at 12:54 AM | Comments (0)

Ganfort granted EU approval

OSN TOP STORY for May 27, 2006
Allergan’s Ganfort, a combination of bimatoprost and timolol, is indicated for the reduction of IOP in patients with open-angle glaucoma of ocular hypertension, who are insufficiently responsive to topical beta blockers or prostaglandin analogues, Allergan said.
Ganfort has been approved for once-daily dosing, which Allergan said will help improve patient compliance. According to the release, Ganfort showed 40% less hyperemia than bimatoprost monotherapy in clinical trials.

Posted by aman at 12:47 AM | Comments (0)

Optical Coherence Tomography Measurement of Retinal Nerve Fiber Layer After Acute Primary Angle Closure With Normal Visual Field

AJO May 2006
Twenty-eight patients who had a single unilateral APAC attack associated with normal visual fields at three months after remission and 28 single eyes from normal controls were enrolled. Duration of APAC attack was 5.9 ± 2.7 hours. Comparisons of average RNFL thickness and RNFL thickness in four quadrants and in 12-o’clock-hour segments of the attacked eyes, unaffected fellow eyes, and normal controls were made using fast RNFL thickness (3.4) of Stratus optical coherence tomography.
Results
Significant differences were demonstrated comparing the inferior-quadrant RNFL thicknesses for the attacked eyes with those of the normal controls (P = .02) and fellow eyes (P = .02) using one-way analysis of variance with Tukey’s tests.

Posted by aman at 12:31 AM | Comments (0)

Correlation Between Retinal Nerve Fiber Layer Thickness and Central Corneal Thickness in Patients With Ocular Hypertension: An Optical Coherence Tomography Study

AJO May 2006
Fifty-one eyes of 51 patients with OHT and 35 eyes of 35 normal subjects. Both groups were stratified into thin (CCT ≤555 μm) and thick (CCT >555 μm) cornea subsets. Ocular hypertensives were further stratified by CCT into ≤555 μm, 556 to 588 μm, and >588 μm subsets. observation procedure: RNFL thickness (average, superior average, and inferior average) and ONH parameters were measured by OCT. CCT was measured by ultrasonic pachymetry. main outcome measures: Correlation between CCT and OCT measurements of RNFL and ONH parameters.
In the OHT group, CCT correlated significantly with all three RNFL measurements (Pearson’s coefficient r = 0.412, 0.484, and 0.380, respectively) but with only four ONH parameters (cup-to-disk area ratio, cup area, rim area, and horizontally integrated rim width; r = −0.459, −0.283, 0.421, and 0.436, respectively). The RNFL in ocular hypertensives with CCT ≤555 μm was significantly thinner than in those with thick corneas (analysis of variance, post hoc Bonferroni comparisons, P < .001). RNFL thickness of normal subjects and ocular hypertensives with CCT >555 μm were similar.
Conclusions
Ocular hypertensives with CCT ≤555 μm may represent patients who have either very early undetected glaucoma or an inherent structural predisposition to glaucomatous damage. This may in part explain the higher risk of these patients for progression to glaucoma.

Posted by aman at 12:27 AM | Comments (0)

May 27, 2006

B&L's newest excimer laser approved

Ophthalmology Times May 1, 2006

Rochester, NY—The FDA has approved Bausch & Lomb's 100 Hz excimer laser, the 217z100, for use as part of the Zyoptix personalized laser vision-correction system for refractive surgery. The combination of beam diameters and laser speed of the 217z100 makes it among the fastest laser vision correction treatment times available in the United States, according to the company. The laser operates at twice the speed of the Bausch & Lomb system currently on the U.S. market, the company said. "The 217z100 laser reduces treatment time with the Bausch & Lomb Zyoptix system by half. This reduction in treatment time comes on the heels of dramatic efficiency gains already achieved through a number of recent upgrades to the Zyoptix system," said Bob Anello, Bausch & Lomb's director of refractive marketing. The new 217z100 laser is expected to be commercially available in the United States by July, along with an upgrade path to allow current users of the Zyoptix laser to access the faster technology.

Posted by mehdi khanlari at 10:53 PM | Comments (0)

Dry eye therapies improve stromal HSK frequency, severity

Ophthalmology Times May 15, 2006

Norfolk, VA—Topical cyclosporine emulsion 0.05% (Restasis, Allergan) and/or punctal occlusion may be considered for the management of stromal herpes simplex keratitis (HSK) and concomitant dry eye, said John D. Sheppard, MD.The suggestion for using those modalities was based on the findings of a retrospective study that found both punctal occlusion and topical cyclosporine independently reduced the frequency and duration of HSK recurrences. A third subgroup of patients who had previously undergone punctal occlusion was also observed to benefit with reduced frequency of HSK recurrences after starting topical cyclosporine, although duration of the recurrent episodes was not significantly reduced.......In the year prior to treatment with either occlusion or cyclosporine, the mean annual HSK recurrence rates in the punctal cautery, cyclosporine, and punctal cautery + cyclosporine groups were 2.1, 1.8, and 0.58 episodes/year, respectively. During follow-up, the mean annual HSK recurrence rate was reduced significantly to ≤0.45 episodes/year in both the punctal cautery and cyclosporine groups. Among patients who began cyclosporine treatment after punctal cautery, there was also a minimally significant reduction in the mean recurrence rate to 0.40 episodes/year.The mean duration of HSK recurrences in the punctal cautery, cyclosporine, and punctal cautery + cyclosporine groups were 3.4, 3.2, and 2.2 months, respectively. A reduction in recurrence duration was also observed in all three groups, although only the changes in the punctal cautery and cyclosporine groups were statistically significant. During follow-up, mean recurrence durations in the three treatment groups were 2.4, 2.5, and 2.0 months, respectively.

Posted by mehdi khanlari at 10:31 PM | Comments (0)

Cataract surgery benefit on visual function largely durable

Ophthalmology Times May 15, 2006

Lund, Sweden—The effect of cataract surgery for improving visual function decreases over time, but a high proportion of patients continue to enjoy the benefits of surgery up to 8 years after the procedure, according to a study undertaken by Swedish ophthalmologists.Mats Lundström, MD, PhD, Phone: 011 46 455 735 135, E-mail: mats.lundstrom@ltblekinge.seIn a recently published paper, Mats Lundström, MD, PhD, and Eva Wendel reported results from their investigation of the duration of benefit of cataract extraction [Br J Ophthalmol 2005;89:1017-1020]. In April 2003, they mailed questionnaires to 523 patients who had undergone cataract surgery at Blekinge Hospital, Karlskrona, Sweden, between March 1995 and March 2002. More than 90% of those individuals returned the surveys; 445 answered them completely and were included in the analysis.Overall, based on their self-assessment, 77.3% of subjects had improved visual function compared with their preoperative state. In 9.4% of subjects, visual function was unchanged, and scores of the remaining 13.3% indicated worsening.

Posted by mehdi khanlari at 10:16 PM | Comments (0)

PTK reduces bullae formation, pain after cataract surgery

Ophthalmology Times May 15, 2006

New Delhi, India—In eyes with nonresolving corneal edema after cataract surgery, phototherapeutic keratectomy (PTK) appears to be effective for preventing progression to bullous keratopathy and for decreasing pain, reported Jeewan Titiyal, MD........"Pain is mitigated as a result of ablation of the subepithelial nerve plexus. In addition, by ablating Bowman's membrane, the procedure results in increased adhesion between the epithelium and stroma, thereby reducing bullae formation. By reducing corneal thickness, the procedure is also thought to reduce the osmotic workload on the endothelium to enable the efficacy of dehydration by the remaining endothelium and thereby reduce epithelial edema and decrease or stabilize corneal thickness," Dr. Titiyal said.

Posted by mehdi khanlari at 09:12 PM | Comments (0)

May 26, 2006

Continued monitoring indicated for AMD patients who have occult with no classic subfoveal CNV lesions

Archives of Ophthalmology, May 2006
In this fourth report from the Verteporfin in Photodynamic Therapy (VIP) Trial, follow-up angiograms in which classic CNV was identified were re-analyzed to determine how many occult with no classic lesions converted to predominantly classic or minimally classic composition at a follow-up examination. By 24 months, 8 percent of 89 patients had lesions that converted to predominantly classic composition, and 46 percent had minimally classic composition. The authors recommend monitoring, rather than ending follow-up, for these patients. If visual acuity decreases or predominantly classic features develop, photodynamic therapy with verteporfin or pegaptanib sodium injections may be considered, as long as the lesion has not become too large or visual acuity too poor before conversion or deterioration that verteporfin therapy or pegaptanib injections would no longer be meaningful to the patient.

Posted by kjalali at 10:33 PM | Comments (0)

Cataract surgery results in colorful visual experiences for patients

Eyeworld May 2006

Patients undergoing cataract surgery with topical anesthesia had colorful visual experiences during the painless procedure, according to a new scientific article.In a report by Kuang Hu, senior house officer in ophthalmology, and Stephen Scotcher, consultant ophthalmic surgeon, Victoria Eye Unit, Hereford County Hospital, U.K., the researchers suggest pre-op counseling to allay the fears of patients about this ocular experience. Doctors are not sure about the origin of the visual imagery of which artists have created paintings. Colored agents were not used during the routine cataract surgery, but it is possible that the bright operating light that illuminates the eye even partially desensitizes its retinal photoreceptors. It also has been suggested that stimulation of the photoreceptors by ultrasonic energy from the phacoemulsification probe is a reason for the colorful abstract imagery. The report posits that another explanation could be that light from the operating microscope is being refracted into its constituent colors at changing optical interfaces in the eye.Using a deeper level of anesthesia such as retrobulbar or peribulbar injections may block conduction optic nerve function, potentially reducing visual function and the experience of imagery. Even with this deeper level of anesthesia, however, patients still have ocular experiences during cataract surgery.

Posted by mehdi khanlari at 06:36 PM | Comments (0)

Macugen in combination with Avastin booster produces promising early results in wet AMD patients

INDUSTRY NEWS
This study included 26 patients who received one intravitreal injection of Macugen followed two to three weeks later by one intravitreal injection of Avastin and at least two subsequent injections of Macugen. Preliminary results show 34.6 percent of eyes gained three lines or more of vision, 69.2 percent of eyes gained one or more lines of vision, 19.2 percent of eyes had stable vision and 11.5 percent of eyes lost one or more lines of vision.

Posted by kjalali at 10:05 AM | Comments (0)

Wet AMD patients treated with Lucentis show improved visual acuity with five to six doses

INDUSTRY NEWS
Researchers at Bascom Palmer Eye Institute earlier this month released one-year results from an open-label study designed to evaluate the use of optical coherence tomography to determine when patients needed an injection of Lucentis. The average patient in this study received five or six injections over a one-year period. Overall, average vision improved in the treated eye almost two lines after one year. While 82 percent of patients had the same or better vision after one year and 35 percent of patients experienced a two-fold improvement in vision as defined by gaining three lines of vision on a standardized visual acuity chart. The improvement in vision was associated with a decrease in the leakage of fluid from the abnormal blood vessels in these eyes.

Posted by kjalali at 09:57 AM | Comments (0)

May 25, 2006

Link between contrast sensitivity and aberrations not found

Eyeworld May 2006

There appears to be no correlation between contrast sensitivity and aberrations of both lower- and higher-order type, said Pravin K. Vaddavalli, MBBS, L.V. Prasad Eye Institute, Hyderabad, India. In a study of 80 eyes with a UCVA greater than or equal to 20/16, researchers found that second- and third-order aberrations were higher in subjects with higher contrast sensitivity, and fourth- and fifth-order aberrations were lower in subjects with higher contrast sensitivity. Researchers also found that third- and fourth-order aberrations showed a positive correlation with age. The testing distance for contrast sensitivity was one meter. Patients who had active ocular disease were excluded from the study, had past ocular surgery, past ocular trauma, and corneal pathology (such as a scarring).

Posted by mehdi khanlari at 07:24 PM | Comments (0)

New “LITE” tool on the horizon

Eyeworld May 2006
Vision tool designed to help blind individuals with navigation

The blind may have more options for sight in the near future.
A new tool is under development that is designed to enable the blind to move about with more ease. Called the LITE, its developers said it will reduce the need to rely on seeing-eye dogs and canes.
The LITE is designed to be worn as a pair of sunglasses.
“The possibilities of these glasses working on blind people are great. They haven’t been tested yet, but I could see them helping people get around and do the things that others take for granted,” said inventor Robert Martinez of IntroMark Inc., Honolulu. The design is voice activated, and it features a global positioning system. Users verbalize commands, and the system responds with a computerized voice. The tool maps out directions, distance, and other variables that the wearer may encounter en route to the destination.
The design of the LITE is currently available for licensing or sale to manufacturers or marketers. The price of the tool was undetermined at press time.

Posted by mehdi khanlari at 07:24 PM | Comments (0)

May 22, 2006

Supplementation may improve vision in some people with dry AMD

OSN BREAKING NEWS
LISBON, Portugal — Regular consumption of high-dose antioxidants seems to offer a visual benefit to some patients with dry age-related macular degeneration, a speaker here said.
The study was a prospective, randomized, 12-month trial of 90 patients with atrophic AMD, Dr. Richer said. Patients were separated into three groups, one receiving 10 mg lutein supplementation alone, a second receiving a lutein formulation with broad-spectrum antioxidants and vitamin supplement called Ocupower, and a third receiving a placebo.
At 12 months, visual improvement was 36% in the lutein group and 43% in the lutein and antioxidants group.

Posted by aman at 10:23 PM | Comments (0)

Temporal hinge may be preferable for IntraLase flap

OSN BREAKING NEWS
A temporal hinge may be the safest and most effective option when using a femtosecond laser to create LASIK flaps, said a surgeon speaking here at the OSN Rome Symposium.

“The original microkeratomes were designed to create a nasal hinge. However, superior hinge rapidly gained popularity because of the less likelihood of gravitation-induced flap distortion. But the superior approach also has limitations,” said Dmitri Azar, MD. “When the flap is everted, it may rest on the upper eyelid or eyelashes, which are a potential source of epithelial scratching and infection. In addition, it has been hypothesized that the effects of a superior cut on the long ciliary nerves might have a role in the onset of dry eye after LASIK.”

Because of technical difficulty and limited availability of the option in most microkeratomes, “a temporal approach was never really considered,” Dr. Azar said. He said there are several advantages to using a temporal hinge.

“It leaves a larger stromal surface available for ablation, which produces better treatments with less chances of developing glare and halos,” he said. The surgeon can also create a larger hinge without sacrificing exposed stromal surface area, adding stability to the flap, Dr. Azar said.

“In addition, the long ciliary nerves are not affected, which lowers the chances of developing dry eye symptoms. Finally, since most trauma to the eye comes from a temporal to a nasal direction, with a temporal hinge there would be less chance of flap dislocation and tearing of the flap,” he said.

Dr. Azar added that patients with mixed against-the-rule astigmatism, both hyperopic and myopic, may benefit from a temporal hinge, which leaves plenty of space for the characteristic oval treatment pattern along the vertical axis.

“The hinge will not interfere at all with the treatment zone,” he said. Conversely, a superior hinge might be preferable for patients with with-the-rule astigmatism, he said.

Posted by aman at 10:05 PM | Comments (0)

Computer modelling study of the mechanism of optic nerve injury in blunt trauma

BJO June 2006
A finite element model of the eye, the optic nerve, and the orbit with its content was constructed to simulate blunt object trauma. We used a model of the first phalanx of the index finger to represent the blunt body. The trauma was simulated by impacting the blunt body at the surface between the globe and the orbital wall at velocities between 2–5 m/s, and allowing it to penetrate 4–10 mm below the orbital rim.
Results: The impact caused rotations of the globe of up to 5000°/s, lateral velocities of up to 1 m/s, and intraocular pressures (IOP) of over 300 mm Hg. The main stress concentration was observed at the insertion of the nerve into the sclera, at the side opposite to the impact.
Conclusions: The results suggest that the most likely mechanisms of injury are rapid rotation and lateral translation of the globe, as well as a dramatic rise in the IOP. The strains calculated in the study should be sufficiently high to cause axonal damage and even the avulsion of the nerve. Finite element computer modelling has therefore provided important insights into a clinical scenario that cannot be replicated in human or animal experiments.

Posted by aman at 09:59 PM | Comments (0)

Expression of insulin-like growth factor binding protein-3 in pterygium tissue

BJO June 2006
DNA microarray analysis of primary pterygium tissue was carried out using uninvolved conjunctiva tissue as a comparison for gene expression levels. Real time polymerase chain reaction (PCR) was used to verify the mRNA level of expression for genes changed in pterygium. Western blot analysis and immunohistochemistry showed protein expression levels and the tissue distribution.
Conclusion: Decreased levels of IGFBP3 protein have been strongly correlated with the presence of cancer. Identification of the low level of expression of IGFBP3 in pterygium suggests that the pathway controlling cell proliferation has lost an important control mechanism, which may explain the continued growth of pterygium.

Posted by aman at 09:44 PM | Comments (0)

Diabetic cataract removal: postoperative progression of maculopathy—growth factor and clinical analysis

BJO June 2006
Diabetic cataract extraction can be frequently complicated by macular oedema, progression of retinopathy, or development of iris neovascularisation. The pathogenesis of these complications may be the result of changes in the concentration of angiogenic and anti-angiogenic cytokines in the immediate postoperative period. The study aims to prospectively analyse this.
Uneventful phacoemulsification with intraocular lens implant was performed in seven eyes of six patients with diabetic retinopathy ranging from severe non-proliferative to quiescent proliferative. Patients were reviewed 1 day, 1 week, 1 month, and 3 months after surgery with fundus fluorescein angiography (FFA) and aqueous sampling. Each sample was analysed for VEGF, HGF, Il-1 ß (pg/ml), and PEDF (µg/ml) by sandwich ELISA.
Results: Clinically significant macular oedema (CSMO) occurred in one patient although increased macular hyperfluorescence occurred in three patients on FFA at 1 month. VEGF 165 concentration increased 1 day after surgery from a median baseline of 68 pg/ml (range 22–87 pg/ml) to 723 pg/ml (range 336–2071) at day 1. By 1 month it had decreased to 179 (range 66–811 pg/ml). HGF concentrations steadily increased over the month while IL-1 ß and PEDF concentrations demonstrated an acute rise on day 1 after surgery and then IL-1ß returned to baseline concentrations while PEDF decreased to below baseline.
Conclusion: These results confirm altered concentrations of angiogenic and antiangiogenic growth factors after cataract surgery, which may induce subclinical and clinical worsening of diabetic maculopathy.

Posted by aman at 09:38 PM | Comments (0)

Risk factors for perforation in microbial corneal ulcers in north India

BJO June 2006
Two groups of 60 patients each, with perforated corneal ulcers and healed/healing corneal ulcers, respectively, were recruited in a case-control study conducted in northern India. The cases and controls were matched by age and time of presentation. A standardised proforma was used to identify potential predisposing factors for demographic, social, medical, ocular, and treatment history. All participants underwent a detailed ocular examination. Corneal scrapings were performed where relevant.
Results: The characteristics associated with corneal perforation in microbial keratitis were outdoor occupation (p = 0.005), illiteracy (p = 0.02), excessive alcohol use (p = 0.03), history of "something falling into eye" (p = 0.003), trauma with vegetable matter (p = 0.008), vision less than counting fingers at referral (p<0.001), central location of ulcer (p<0.001), lack of corneal vascularisation (p<0.001), delay in starting initial treatment (p<0.001), failure to start fortified antibiotics (p<0.001), and monotherapy with fluoroquinolones (p = 0.002). The lack of corneal vascularisation (OR 6.4, 95% CI 4.2 to 13.5), delay in starting initial treatment (OR 35.6, 95% CI 6.9 to 68.2), and failure to start fortified antibiotics (OR 19.9, 95% CI 2.7 to 64.7) retained significance on a logistic regression model.

Posted by aman at 09:30 PM | Comments (0)

May 21, 2006

Bausch & Lomb acquires license to patent retinal disease treatment

Eyeworld weekly news

drug SurModics (Eden Prairie, Minn.) announced it granted Bausch & Lomb (Rochester, N.Y.) an exclusive license to patents relating to the use of Genistein in the treatment and prevention of retinal diseases, according to a SurModics news release. Genistein is a soy isoflavone with anti-oxidant and anti-vascular endothelial growth factor (VEGF) activity that has been shown to reduce retinal vascular leakage in diabetic animals

Posted by mehdi khanlari at 11:51 PM | Comments (0)

Comparison of higher-order aberrations after wavefront-guided laser in situ keratomileusis and laser subepithelial keratomileusis
Eyeworld may 2006

Investigators prospectively compared higher-order aberrations from 70 wavefront-guided laser in situ keratomileusis (LASIK) to those in another 70 that had undergone laser subepithelial keratomileusis (LASEK) to correct myopia. They found no significant differences in manifest refraction or best-corrected or uncorrected visual acuity between the groups. They determined that at one month after surgery for scotopic pupils, the average root mean square wavefront error of HOAs was significantly smaller in the wavefront-guided LASIK group. Likewise spherical aberration, coma, and individual Zernike coefficients were also significantly smaller in the wavefront-guided LASIK group. However, between the three- and six-month marks these differences in higher order aberrations disappeared. The conclusion reached was by the three-month postoperative mark there was no difference in higher order aberrations between LASIK and LASEK in scotopic conditions. Investigators also determined that particularly for spherical aberration there was a different postoperative corneal response at work. Because higher order aberrations change during the postoperative period, even the most precise ablation could not attain aberration-free results.

Posted by mehdi khanlari at 11:51 PM | Comments (0)

horizontal w-t-w versus capsular bag size

Eyeworld May 2006

.....Investigators found very little correlation between the horizontal limbus measurement and capsular bag size. However, a weak correlation was found between capsular bag size and vertical limbus measurements.“If we look at the linear regression of lens dimension, either in the horizontal or in the vertical meridian, and correlated these with limbus size, we then obtain the linear regression value r2,” Dr. Khng said.This r2 value gives an idea of how much variation in lens size there is as a result of limbus size. The r2 value for the vertical dimension was 0.13 (p=0.0012), a number that Dr. Khng sees as offering a weak yet statistically significant correlation. Meanwhile, the r2 value for the horizontal dimension was 0.031 (p=0.1220). Investigators determined that there was no significant correlation.Practitioners can benefit from the correlation between vertical limbus measurements and capsular bag size, believes Dr. Khng. This is a measurement that could potentially be used in the operating room short of obtaining imaging through methods such as anterior segment optical coherence tomography (OCT).
“Because the capsular bag is roughly round, if you wanted to get an idea of what the capsular bag size was, I think we should look at the vertical limbus size as a proxy to what the bag size might be,” Dr. Khng said. “If the patient is already on the table and you had to put in a capsular tension ring and there was no opportunity for you to go for OCT, you might get a better idea just by measuring the vertical limbus size.”He urged practitioners, however, to move away from the paradigm that the horizontal white to white is the way to go.“I think we have to stop using the horizontal white to white because there is absolutely no correlation between the horizontal white to white and the capsular bag size,”

Posted by mehdi khanlari at 11:11 PM | Comments (0)

May 19, 2006

Speciality views and news,May,2006
Clear lens extraction may be useful in children with high anisometropic myopia

At a recent meeting of the American Association for Pediatric Ophthalmology and Strabismus, researchers reported their experiences with clear lens extraction in children (age range, 4 to 20) whose myopia averaged –16.55 D. Some of the eyes received an IOL. After a mean follow up of 45.6 months, the average myopia corrected was 15.8 D. Though visual acuity only mildly improved in all eyes, serious complications were uncommon. Specialty News & Views authors conclude that after more study this technique might be useful in younger children.

Posted by afarahi at 11:11 PM | Comments (0)

Speciality News and Views,May,2006
Clear lens extraction may be useful in children with high anisometropic myopia

At a recent meeting of the American Association for Pediatric Ophthalmology and Strabismus, researchers reported their experiences with clear lens extraction in children (age range, 4 to 20) whose myopia averaged –16.55 D. Some of the eyes received an IOL. After a mean follow up of 45.6 months, the average myopia corrected was 15.8 D. Though visual acuity only mildly improved in all eyes, serious complications were uncommon. Specialty News & Views authors conclude that after more study this technique might be useful in younger children.

Posted by afarahi at 11:11 PM | Comments (0)

May 18, 2006

Simple regression formula for intraocular lens power adjustment in eyes requiring cataract surgery after excimer laser photoablation

JCRS Pages March 2006
Samuel Masket, MD, Seth Everett Masket, PhD
To develop a simple and accurate method for determining appropriate IOL power in cataract patients who had prior PRK for myopia or hyperopia, because laser vision corrective surgery interferes with traditional keratometry and corneal topography, rendering IOL power calculations inaccurate.
Methods
Based on the empiric experience of the senior author, an IOL power correction factor that was proportional to the prior PRK was determined and applied to the IOL power calculated by the IOLMaster (Zeiss). It was necessary to add to the predicted IOL power in eyes with prior myopic laser ablation, whereas eyes having prior hyperopic laser vision correction required a reduction in the IOL power. The correction factor was applied to 30 eyes that required cataract surgery at some time after laser refractive surgery.
Conclusions:
A simple IOL power corrective adjustment regression formula allowed accurate determination of IOL power after laser refractive photoablation surgery. The weakness of the current method is that knowledge of the amount of prior laser vision correction is necessary.

Posted by alireza habibollahi at 10:46 PM | Comments (0)

Accurate IOL power calculation after myopic LASIK bypassing corneal power

JCRS March 2006
26 of 51

USA,9 eyes of 9 patients who had PE after LASIK using our method for IOL calculation. This new method assumes the patient never had myopic LASIK to calculate IOL power and then targets the IOL at the pre-LASIK amount of myopia. The pre-LASIK keratometry values, pre-LASIK manifest refraction, and the current axial length are placed in the Holladay formula, bypassing the post-LASIK corneal power. In theory, assuming that the patient had satisfactory LASIK results, the correct IOL can then be determined.
Results
The mean post-op SE was +0.03 diopter.In all 9 eyes, our method consistently chose the most accurate and precise IOL compared with other methods.

Conclusions
The new method of calculating IOL power after LASIK provided excellent results and the most accurate and precise results to date.

Posted by alireza habibollahi at 10:40 PM | Comments (0)

Descemet's stripping with endothelial keratoplasty in 200 eyes: Early challenges and techniques to enhance donor adherence

JCRS March 2006
USA.To describe early challenges and techniques to promote donor tissue adherence in Descemet's stripping with endothelial keratoplasty (DSEK).
The first 200 consecutive cases of DSEK performed by a single surgeon were analyzed retrospectively. Follow-up was 7 to 20 months for 124 eyes and 2 to 6 months for 76 eyes. The surgical technique consisted of stripping Descemet's membrane and endothelium from the recipient's central cornea and transplanting an 8.0 to 9.0 mm disc of donor endothelium and posterior stroma through a 5.0 mm incision, with sutures used only to close the incision.

Results
The most frequent challenge was inadequate donor attachment. Using techniques to remove fluid from the donor–recipient graft interface, the donor detachment rate in the last 64 cases was 6%, with half attributable to patient eye rubbing. Detached grafts were reattached by injecting an air bubble to press the donor against the recipient cornea. There were 7 primary graft failures, with only 1 occurring in the second 100 cases, which primarily used microkeratome-dissected donor tissue. Other complications were infrequent and included pupillary block glaucoma (1), aqueous misdirection syndrome (1), and cataract development in 2 of 27 phakic eyes. The DSEK procedure was performed safely before and after laser in situ keratomileusis (1 each).

Conclusions
Early outcomes in the initial 200 consecutive DSEK procedures suggest the technique provides significant advantages over penetrating keratoplasty, including more rapid healing, more predictable refractive outcomes, and better retention of corneal strength and integrity. Although donor adherence was more challenging, DSEK was technically easier and should be less traumatic to anterior chamber structures than earlier posterior grafting techniques

Posted by alireza habibollahi at 10:32 PM | Comments (0)

Capsular stabilization device to preserve lens capsule integrity during phacoemulsification with a weak zonule

JCRS March 2006

We describe a new capsular stabilization device for suspending a lens with weak zonular support. It is flexible, 10.0 mm in length, and fashioned from 5-0 nylon. The contact portion is bent at 1.25 mm with an end bifurcating to form a T-shape to minimize stress on the capsular equator. After a continuous curvilinear capsulorhexis is created, the capsular stabilization devices to hook the capsulotomy margin are inserted. The T-shaped end is passed around the anterior capsular flap to fit the curvature of the equator. Phacoemulsification and aspiration using this device was performed in 12 eyes of 9 patients, and the usefulness and complications were analyzed. The capsular stabilization devices suspended the capsule and facilitated safe phacoemulsification in all eyes. Posterior capsule rupture occurred in 2 eyes. None of the cases had notable postoperative complications. This device ensures a stable capsule-iris complex and reduces surgical risks.

Posted by alireza habibollahi at 10:26 PM | Comments (0)

Trypan blue to aid visualization of the vitreous during anterior segment surgery

JCRS March 2006
We describe the usefulness of intracameral injection of trypan blue to highlight vitreous in the anterior chamber. The technique was used in 3 eyes of 3 patients who had vitreous prolapse in the anterior chamber. Trypan blue 0.06% was injected in the anterior chamber under air to visualize and resect the prolapsed vitreous. Trypan blue stained the clear vitreous and improved visualization for a safe and atraumatic vitrectomy. No complications associated with the dye were found.

Posted by alireza habibollahi at 10:22 PM | Comments (0)

Crisscross lensotomy: New explantation technique

JCRS March 2006 Robert H. Osher, MD
Crisscross lensotomy is a new technique for removing a silicone plate intraocular lens (IOL) through a small incision. A case is described in which strategic incisions in the IOL allowed the lens to be explanted in pieces through a 3.0 mm incision. Less invasive surgery may enhance safety in complicated cases.

Posted by alireza habibollahi at 10:16 PM | Comments (0)

May 16, 2006

Hydrophilic acrylic intraocular lens as a drug-delivery system: Pilot study

Journal of Cataract & Refractive Surgery Volume 32, Issue 4 , April 2006, Pages 652-654

Hydrophilic acrylic IOLs (C-flex, Rayner Ltd.), presoaked for 24 hours in commercially available solutions of gatifloxacin (Zymar) or moxifloxacin (Vigamox), were implanted in the capsular bag of 6 rabbits for a total of 12 eyes (6 in each group). Aqueous humor samples were taken 2, 4, and 6 hours after implantation. One rabbit served as a control and had nonpresoaked C-flex IOLs implanted. At the end of the operation, 1 drop of Vigamox was applied to the right eye and 1 drop of Zymar was applied to the left eye of the control rabbit.
Results
High concentrations of both antibiotics were found in all the samples of the eyes implanted with the presoaked IOLs. The concentrations of the antibiotics decreased over time, but even the 6-hour sample concentrations were markedly higher than the concentrations found in the control rabbit after 4 hours.
Conclusion
The results suggest that the Rayner C-flex IOL can be effective as a drug-delivery system for fourth-generation fluoroquinolones.

Posted by mmiraftab at 10:36 PM | Comments (0)

Q-factor customized ablation profile for the correction of myopic astigmatism

Journal of Cataract & Refractive Surgery Volume 32, Issue 4 , April 2006, Pages 584-589

Thirty-five patients were enrolled in a controlled study in which the nondominant eye was treated with the Q-factor customized profile (custom-Q study group) and the dominant eye was treated with wavefront-guided customized ablation (control group). Preoperative and 1-month postoperative high-contrast visual acuity, low-contrast visual acuity, and glare visual acuity, as well as aberrometry and asphericity of the cornea, were compared between the 2 groups. All eyes received laser in situ keratomileusis surgery, and the laser treatment was accomplished with the Wavelight Eye-Q 400 Hz excimer laser.
Results
For corrections up to −9 diopters (D) of myopia, there were no statistically significant differences between the 2 groups regarding any visual or optical parameter except coma-like aberrations (3rd Zernike order), where the wavefront-guided group was significantly better 1 month after surgery (P = .002). For corrections up to −5 D (spherical equivalent), the Q-factor optimized treated eyes had a significantly smaller shift toward oblate cornea: ΔQ15 = 0.25 in Q-factor customized versus ΔQ15 = 0.38 in wavefront-guided treatment (P = .04).
Conclusions
Regarding safety and refractive efficacy, custom-Q ablation profiles were clinically equivalent to wavefront-guided profiles in corrections of myopia up to –9 D and astigmatism up to 2.5 D. Corneal asphericity was less impaired by the custom-Q treatment up to −5 D of myopia.

Posted by mmiraftab at 10:34 PM | Comments (0)

Corneal Ectasia after Photorefractive Keratectomy for Low Myopia

Ophthalmology Volume 113, Issue 5 , May 2006, Pages 742-746

To alert ophthalmologists of the possibility of an aggravation of forme fruste keratoconus after photorefractive keratectomy (PRK).
Corneal ectasia occurred bilaterally after PRK. Retrospective analysis of preoperative videokeratography indicated the existence of forme fruste keratoconus on the left eye.
Conclusions
This article is the first case report of a bilateral corneal ectasia after PRK for low myopia. Even if there is no direct proof to demonstrate that PRK has worsened the evolution of keratoconus, the safety of the PRK procedure in forme fruste keratoconus must be considered.

Posted by mmiraftab at 10:28 PM | Comments (0)

Evidence for Delayed Presbyopia after Photorefractive Keratectomy for Myopia

Ophthalmology Volume 113, Issue 5 , May 2006, Page 741

Compared with normal eyes, in previously myopic eyes treated with first-generation PRK lasers there is a tendency for (1) the optical quality of the retinal image to be reduced at low contrast, (2) the aberrations attributed to the corneal surface to increase, and (3) both measured subjective accommodation and near acuity to be greater than expected. We postulate that the corneal aberrations induced by PRK for myopia may reduce the quality of the retinal image for distance but enhance near acuity by way of a multifocal effect that can delay the onset of age-related near vision symptoms.

Posted by mmiraftab at 10:24 PM | Comments (0)

Retinal Detachment in Myopic Eyes After Phakic Intraocular Lens Implantation

JRS March 2006
In a retrospective, non-comparative, interventional case series, the occurrence of retinal detachment was analyzed in 522 consecutive highly myopic eyes (323 patients) that underwent PIOL implantation. Treatment and results were reviewed. Parameters evaluated were best corrected visual acuity before and after retinal detachment surgery and time between refractive surgery and retinal detachment.
Fifteen (2.87%) eyes presented with retinal detachment after PIOL implantation, with a mean time between surgery and detachment of 24.4±24.4 months (range: 1 to 92 months). The risk of retinal detachment in patients with high myopia corrected by PIOL implantation was 0.57% at 3 months, 1.64% at 12 months, 2.73% at 36 months, and 4.06% at 92 to 145 months (Kaplan-Meier analysis). A comparative study between the group of patients with retinal detachment and the remaining patients without retinal detachment was performed. Differences were found in axial length (30.65±1.97 vs 29.51±2.02; P=.028, one factor-analysis of variance test).
CONCLUSIONS
The risk of retinal detachment in eyes implanted with phakic lenses for the correction of high myopia is higher in eyes with axial length >30.24 mm.

Posted by aman at 08:46 PM | Comments (0)

Statins may help improve ocular circulation

OSN BREAKING NEWS
Statins, already proven to relax blood vessels and reduce cardiovascular disease risks, may be able to improve circulation in the eye as well, according to a study.
Taiji Nagaoka, MD, PhD, and colleagues at Asahikawa Medical College in Japan studied the effects of systemic administration of simvastatin on the retinal circulation after 90 minutes and after 7 days in 12 healthy men. The men were randomized to either 20 mg dose of simvastatin or placebo. The study was repeated 28 days after the first administration course was finished.
There were no significant changes in any retinal circulatory parameters at the 90-minute follow-up. Daily administration of simvastatin for 7 days significantly increased blood velocity and blood flow in retinal arteries and veins but did not significantly change vessel diameter. The IOP significantly decreased at 90 minutes and at 7 days after the simvastatin administration, researchers stated.

Posted by aman at 08:41 PM | Comments (0)

Implanting a Clear Intraocular Lens in One Eye and a Yellow Lens in the Other Eye: A Case Series

AJO May 2006
To describe the color vision disturbance reported by patients in whom a clear intraocular lens (IOL) was implanted in one eye and a yellow-tinted (blue-light-absorbing) IOL in the other eye.
Results
Four of five patients had no spontaneous color vision complaints. When these patients were informed of the unintended mismatch, all remarked that they could perceive a color vision difference, but that it was not bothersome. One of the five patients reported “beige” vision. None of the patients wanted an IOL exchange.
Conclusion
Many patients can tolerate the color vision imbalance that results when a clear IOL is implanted in one eye and a yellow-tinted IOL is implanted in the other eye.

Posted by aman at 12:26 AM | Comments (0)

Bacterial Endophthalmitis After Resident-Performed Cataract Surgery

AJO May 2006
The operative reports of the resident-performed cataract surgeries at San Francisco General Hospital between 1983 and 2002 were reviewed. Cases of culture-positive bacterial endophthalmitis and vitreous loss were identified.
Between 1983 and 2002, three cases (0.11%) of culture-positive bacterial endophthalmitis occurred after 2718 resident-performed cataract extractions. The overall vitreous loss rate was 6.7%. Two endophthalmitis cases were acute (Staphylococcus epidermidis, Streptococcus viridans), presenting within five days of surgeries complicated by vitreous loss, and one case was delayed-onset (Corynebacterium species) after Nd:YAG posterior capsulotomy after uncomplicated cataract extraction.
Conclusions
Despite higher rates of vitreous loss, the rate of endophthalmitis following resident-performed cataract surgery remains comparable with the rates of more experienced surgeons.

Posted by aman at 12:20 AM | Comments (0)

Comparison of Single-Segment and Double-Segment Intacs for Keratoconus and Post-LASIK Ectasia

AJO May 2006
Thirty-seven eyes of 28 patients with keratoconus and post-LASIK ectasia classified into two groups: single-segment group (17 eyes, 11 patients) and double-segment group (20 eyes, 17 patients). Both groups were matched for age, visual acuity (uncorrected, UCVA; best spectacle-corrected, BSCVA), refractive error (sphere, cylinder, spherical equivalent), and keratometry (K) value (flat, steep, average) by t test for equality of means. intervention: Single- or double-segment Intacs procedure with axis of incision for insertion in the steep axis of manifest refraction. main outcome measure: Improvement of acuity, refractive error, K values, and inferior-superior (I-S) ratio.
Results
There was more improvement in UCVA in the single-segment group (nine lines) than the double-segment group (2.5 lines), P < .01; in BSCVA in the single-segment group (2.5 lines) than the double-segment group (<1 line), P < .01; in steep K values in the single-segment group (2.76 diopters ± 2.68) than the double-segment group (0.93 diopters ± 2.01), P = .02; and in I-S ratio in the single-segment group (9.51 ± 7.49) than the double-segment group (4.22 ± 4.82), P = .01; and greater cylinder decrease after Holladay vector analysis in the single-segment group (5.69 diopters ± 3.10) than the double-segment group (1.58 diopters ± 3.09), P < .01.
Conclusions
Single-segment Intacs improved both UCVA and BSCVA by differential flattening of inferior meridian and steepening of superior meridian as reflected by change in I-S ratio.

Posted by aman at 12:10 AM | Comments (0)

Topical Dorzolamide for the Treatment of Cystoid Macular Edema in Patients With Retinitis Pigmentosa

AJO May 2006
Fifteen patients with CME and RP. intervention: A baseline visual acuity and optical coherence tomography (OCT) measurements were obtained in all patients. Each one of them was then treated with topical dorzolamide, three times a day, for at least four weeks in both eyes. main outcome measures: Significant decrease in “foveal thickness” (more than 16%) and “foveal zone thickness” (more than 11%), as measured by OCT.
Thirteen (87%) of 15 patients showed a significant decrease in retinal thickness in at least one eye after use of topical dorzolamide for at least four weeks. Five patients (33%) demonstrated improvement in both eyes. All patients, except one, who responded showed the effect within four weeks, but were monitored for a period of two to nine months (average 4.5 months). Four patients (31%) who showed an initial improvement in macular edema showed worsening with continued treatment.
Conclusions
The present study documents the potential efficacy of topical dorzolamide for treating CME in patients with RP. We observed that some patients may show a “rebound phenomenon” with continued use of the medication; hence, there is a need for careful follow-up in patients being treated.

Posted by aman at 12:07 AM | Comments (0)

May 15, 2006

ISTA reports promising results for macular edema treatment

INDUSTRY NEWS
At the Association for Research in Vision and Ophthalmology’s annual meeting last week, the company reported that patients treated with Xibrom (bromfenac ophthalmic solution) 0.09 percent for acute pseudophakic cystoid macular edema experienced statistically significant improvements in both visual acuity and EDTRS letters gained, which were equivalent to Voltaren Ophthalmic (diclofenac sodium ophthalmic solution) 0.1 percent and Acular (ketorolac tromethamine ophthalmic solution) 0.5 percent after three months of treatment.

Posted by kjalali at 08:37 PM | Comments (0)

May 13, 2006

The Effect of Scleral Buckling Surgery on Corneal Astigmatism, Corneal Thickness, and Anterior Chamber Depth

JRS May 2006
Thirty-two eyes of 32 patients who underwent encircling buckling surgery for rhegmatogenous retinal detachment were included in the study. Fellow eyes comprised the control group. Orbscan II topography system was used to determine the changes in corneal topography, corneal thickness, and anterior chamber depth before surgery and 1 week, 1 month, and 3 months after surgery. Statistical analyses used in the study were independent t test, paired t test, one way analysis of variance, and correlation analyses.
Postoperatively, mean central corneal astigmatism at 1 week, 1 month, and 3 months was 4.3±2.0 diopters (D), 3.3±1.6 D, and 3.1±1.0 D, respectively. The change between 1 week and 3 months was statistically significant. Central cornea was thickened at the first postoperative week. The thickness gradually decreased to the preoperative levels at 3 months. Anterior chamber depth decreased, and the anterior chamber remained shallow after the surgery. The comparison between preoperative (2.94±0.6 mm) and postoperative anterior chamber depth was statistically significant at 1 week (2.57±0.7 mm), 1 month (2.83±0.7 mm), and 3 months (2.73±0.6 mm).
CONCLUSIONS
Corneal changes after scleral buckling surgery were mild to moderate and the cornea almost resumed its preoperative parameters in 3 months’ time. However, the anterior chamber remained shallow during 3 months of follow-up.

Posted by aman at 11:16 PM | Comments (0)

Corneal and Epithelial Thickness in Keratoconus: A Comparison of Ultrasonic Pachymetry, Orbscan II, and Optical Coherence Tomography

JRS May 2006
Twenty individuals with keratoconus and 20 controls (without keratoconus) were enrolled. The Orbscan II was used to locate the steepest area of the cornea, which was taken to represent the cone apex. Each instrument was used to obtain four total corneal thickness measurements—from the cone apex, corneal center, mid-nasal, and mid-temporal cornea. Optical coherence tomography scans were analyzed to provide epithelial and stromal thickness readings.
In individuals with keratoconus, mean central corneal thickness (CCT) measured by ultrasonic pachymetry, Orbscan, and OCT was 494.2±50.0 µm, 438.6±47.7 µm, and 433.5±39.7 µm, respectively. The central keratoconic cornea was 57.7 µm thinner than the normal cornea (post-hoc P<.001). The cone apex was thinner than the central cornea (P<.001). Keratoconic epithelium was 48.2±5.5 µm centrally and 42.1±4.5 µm at the apex. Central keratoconic epithelium was 4.7 µm thinner and central keratoconic stroma was 57.8 µm thinner than the normal cornea (P<.001, respectively). Comparing instruments, Orbscan and OCT correlated in CCT measurement (r=0.890) and apical thickness (r=0.846). All instruments produced similar readings for mid-nasal and mid-temporal corneal thickness in participants with keratoconus (P>.05).
CONCLUSIONS
Ultrasonic pachymetry produced the highest corneal thickness readings in the center and apex, compared to Orbscan II and OCT. Centrally, the total cornea, epithelium, and stroma were thinner in individuals with keratoconus than in normal individuals

Posted by aman at 11:06 PM | Comments (0)

Centration Analysis of Ablation Over the Coaxial Corneal Light Reflex for Hyperopic LASIK

JRS May 2006
To analyze postoperative topographic centration when the coaxially sighted corneal light reflex was used for laser centration in hyperopic LASIK.
Centration photographs of 21 eyes (12 patients) that underwent hyperopic LASIK with centration over the coaxially sighted corneal light reflex were reviewed to determine the distance from the entrance pupil center to the coaxially sighted corneal light reflex. Postoperative ablation centration was determined topographically at day 1 and 3 months by four different methods. The difference between the actual decentration and the decentration that would have occurred had the ablation been centered over the entrance pupil center was calculated.
The mean deviation of the coaxially sighted corneal light reflex from the entrance pupil center preoperatively was 0.34±0.24 mm nasal or 4.5±3.0°. At 1 day, the average decentration was 0.10 mm or 1.3° temporal. The mean decentration that would have occurred if the ablation had been centered over the entrance pupil center was 0.44 mm or 5.5° temporal. At 3 months, the average decentration was 0.07 mm or 0.25° temporal. The mean decentration that would have occurred if the ablation had been centered over the entrance pupil center was 0.45 mm or 5.6° temporal. Mean uncorrected visual acuity (logMAR) improved 3 lines from 0.54±0.14 (20/70) to 0.22±0.17 (20/32). No eye lost >2 lines of best spectacle-corrected visual acuity (BSCVA); 2 (10%) eyes lost 1 line of BSCVA at 3-month follow-up.
CONCLUSIONS
Excellent centration in hyperopic ablation is possible even in eyes with positive angle kappa when the ablation is centered over the corneal light reflex.

Posted by aman at 10:56 PM | Comments (0)

Correction of Presbyopia by Technovision Central Multifocal LASIK (PresbyLASIK)

JRS May 2006
Jorge L. Alió, MD, PhD
Twenty-five patients (50 eyes) underwent presbyLASIK in an open-label, prospective, non-comparative pilot study. Mean patient age was 58 years (range: 51 to 68 years), mean preoperative spherical equivalent refraction was +1.6±0.63 diopters (D) (range: +0.50 to +3.00 D), and mean spectacle near addition was +2.27±0.37 D (range: +1.75 to +3.00 D). The ablation pattern was performed with proprietary software from Technovision using an H. Eye Tech. excimer laser platform.
Mean postoperative spherical equivalent refraction was -0.37±0.55 D (range: -1.50 to +1.00 D) and mean spectacle near addition was +1.72±0.34 D (range: +1.25 to +2.25 D). After 6 months, 16 (64%) patients achieved a distance uncorrected visual acuity (UCVA) of >20/20 and 18 (72%) patients achieved a near UCVA of >20/40. Seven (28%) patients lost a maximum of 2 lines of best spectacle-corrected visual acuity (BSCVA). The safety index for distance was 0.98 binocular and for near was 0.99 binocular. After 6 months, no significant change was noted in contrast sensitivity at 1.5 cycles/degree. A significant mean reduction was found at spatial frequencies of 3, 6, 12, and 18 cycles/degree (P<.001). There was a significant change in corneal aberrations after surgery. The coefficients for coma increased and the coefficients for spherical aberrations decreased. A significant decrease was noted in point spread function values (P=.0018).
CONCLUSIONS
Central presbyLASIK may be used to provide improvement in functional near vision in patients with presbyopia associated with low and moderate hyperopia. However, factors involved in the loss of BSCVA in some cases and loss in vision quality should be further clarified prior to its general use.

Posted by aman at 10:50 PM | Comments (0)

Rhegmatogenous Retinal Detachment After LASIK for Myopia

JRS May 2006
Hooshang Faghihi, MD; Kamran Hodjat Jalali, MD; Ali Amini, MD; Hassan Hashemi, MD; Akbar Fotouhi, MD, MPH; Mohammad Riazi Esfahani, MD
The medical records of 49 patients with rhegmatogenous retinal detachment after LASIK were reviewed. The incidence of rhegmatogenous retinal detachment after LASIK was determined and potential risk factors were evaluated.
LASIK was performed on 59,424 eyes with spherical equivalent refraction (SE) ranging from -0.75 to -26.50 diopters (D) (mean: -6.10±3.5 D). Forty-nine eyes developed rhegmatogenous retinal detachment between 1.5 and 76 months (mean: 27.3±21.7 months) after LASIK. The mean preoperative refractive error in these eyes was -8.6±3.9 D. Mean age of these patients was 38.2±11.2 years. Thirty-five (71.4%) patients were male. The cumulative incidence of rhegmatogenous retinal detachment was 0.082% (95% confidence interval [CI]: 0.061-0.109), and the yearly incidence was 0.032% (95% CI: 0.023-0.042) after LASIK. The most frequent location of the retinal breaks was the superior temporal quadrant (22.7%). Male sex, older age, and higher preoperative myopia were significantly related to the incidence of rhegmatogenous retinal detachment after LASIK (P<.001).
CONCLUSIONS
Based on the results of this study, following the treatment of high-risk peripheral retinal lesions, LASIK did not appear to be an additional risk factor for the development of rhegmatogenous retinal detachment after LASIK in our patients; however, patients should be informed of the possibility of this complication as a consequence of myopia. Patients who are male, older in age, and have high myopia preoperatively may be at increased risk.

Posted by aman at 10:44 PM | Comments (0)

Interface Corneal Edema Secondary to Steroid-induced Elevation of Intraocular Pressure Simulating Diffuse Lamellar Keratitis

JRS May 2006
Retrospective observational case series. Diffuse interface edema secondary to steroid-induced elevation of IOP was observed after LASIK simulating diffuse lamellar keratitis (DLK) in 13 eyes. Mean patient age was 31.4±5.3 years. Patients were divided into two groups according to provisional misdiagnosis: DLK group (group 1) comprised 11 eyes and infection group (group 2) comprised 2 eyes (microbial keratitis). Mean follow-up was 8.1±0.5 weeks.
In the DLK group, typical diffuse haze was confined to the interface and extended to the visual axis, impairing vision in all eyes. Provisional diagnosis was late-onset DLK and topical steroids were started. Repeat examination showed elevated IOP as measured at the corneal center and periphery using applanation tonometry (mean 19.1 mmHg and 39.5 mmHg, respectively), causing interface edema with evident interface fluid pockets. Steroids were stopped and topical anti-glaucoma therapy was started. The interface edema decreased and at the end of follow-up the corneal transparency was restored and IOP dropped to normal values. The infection group demonstrated a microbial keratitis-like reaction and underwent flap lifting and interface wound debridement and biopsy with administration of fortified antibiotics and steroids. After elevated IOP was detected, steroids and antibiotics were stopped and topical anti-glaucoma therapy was started, resulting in the resolution of the interface edema.
CONCLUSIONS
Interface fluid syndrome secondary to steroid-induced elevation of IOP might develop in steroid responders after LASIK with a misleading clinical picture simulating DLK or infectious keratitis. Management includes stopping topical steroids and starting topical anti-glaucoma therapy.

Posted by aman at 10:37 PM | Comments (0)

Probing advised near 8 months of age in congenital nasolacrimal duct obstruction

OSN BREAKING NEWS
The randomised, prospective study was conducted in Lyon, France on two groups of infants who were between 3 and 12 months old. One of the groups was kept under medical surveillance and occasional infection treatment, while the second group underwent probing.
Results demonstrated that between the ages of 3 and 8 months, there is no statistically significant difference between the two methods. Both had a comparable rate of success (86%), the study found. However, probing was demonstrated to have a more rapid healing effect.
“With probing, the delay of healing was very short, between 10 and 20 days, while medical treatment took more than 2 months,” Dr. Ruban said
On the other hand, the rate of spontaneous healing was constantly decreasing with age. After 8 months of age, less than 8% of children had spontaneous healing.
Around the age of 8 months, if not earlier, probing should be the solution that we offer to these patients, without any further delay,” Dr. Ruban concluded.

Posted by aman at 10:31 PM | Comments (0)

May 06, 2006

A look at the newest visco

Eyeworld June 2006

There are three broad classes of ophthalmic viscosurgical devices: viscoadaptive, higher viscosity cohesive, and lower viscosity dispersive. But the newest ophthalmic viscosurgical device (OVD) from Alcon Laboratories (Fort Worth, Texas) does not fit into any of the existing categories.DisCoVisc (hyaluronic acid 1.6%–chrondroitin sulfate 4%) is a dispersive OVD,It behaves like a dispersive when a surgeon performs phacoemulsification and protects the endothelium well, Dr. Modi said. But clinically, it behaves like a cohesive whenit needs to be removed. DisCoVisc does not fit into any existing categories, so he proposed a new category called “viscous dispersive” in the November 2005 issue of Journal of Cataract & Refractive Surgery.

Posted by mehdi khanlari at 10:36 PM | Comments (0)

Age-related cataract hospitalizations and phacoemulsification

Eyeworld June 2006

Age-related cataract hospitalizations increase during spring and fall and decrease during summer and winter, according to a study by Alan M. Leong, M.D. and Eric J. Crighton, M.D., Sunnybrook and Women’s College Health Sciences Centre, Toronto, Canada. The study was published in the February issue of Biomed Central Ophthalmology.
The study also found that the downward trend in age-related cataract hospitalizations coincides with an increase in phacoemulsification—for both genders. During the study period, hospitalization rates for age-related cataracts decreased from about 50 to 55 per 100,000 to approximately one to two per 100,000, while phacoemulsification grew more than 100-fold. The physicians said that the most likely explanation for the decreases in hospitalizations during summer and winter is that they took place during the months that physicians and surgeons requested vacation time and were unlikely to schedule elective surgical procedures. The study noted several limitations. It did not fully address potential explanatory factors for the hospitalization patterns, and the physicians were unable to measure seasonal variations in patient use of other health services such as emergency department and physician visits.

Posted by mehdi khanlari at 10:29 PM | Comments (0)

CTRs prevent PCO

Eyeworld June 2006

Posterior Capsule Opacification (PCO) is significantly less in eyes that undergo Capsular Tension Ring (CTR) implantation, according to a poster by Simona Degli Espoti, M.D., and colleagues, Department of Pathophisiological Optics, University of Bologna, Italy.Additionally, this study found that the effect of the CTR on the PCO is more evident when a hydrophobic acrylic IOL is used. The CTR reduces the space in between the posterior capsule and the IOL plate. If the edge of the anterior capsule is far from the IOL plate and from the posterior capsule, the fibromuscolar differentiation and the migration of anterior cells can’t occur because the CTR prevents the collapse of the capsular bag. The CTR can’t be routinely implanted, as this surgical procedure may present some risks, but its implant has to be considered in young patients, in myopic ones, and in ones with a high retinal risk.

Posted by mehdi khanlari at 10:29 PM | Comments (0)

Inadvertent insertion of an opposite-power

Eyeworld June 2006

A case report led by Tetsuro Oshika, M.D., Department of Ophthalmology, University of Tsukuba, found that patients who received incorrect lenses had a large amount of post-op refractive error and were therefore unsatisfied with the outcome of a procedure that was otherwise successful. Doctors found that the mistake was due to unclear packaging of IOLs.The case study centered an 82-year-old woman with a cataract and high myopia. It was found that she had an uneventful phacoemulsification, but an improper IOL implantation. An IOL of -5.0D was inadvertently inserted instead of a +5.0D IOL, and her visual acuity was reduced.A careful examination of the packaging of the IOLs shows that positive and negative are identical in design and color except for an easily-overlooked, small negative sign before the diopter label. These doctors have manually drawn a color line on the minus D box so that opposite-power IOLs can be easily distinguished

Posted by mehdi khanlari at 12:10 PM | Comments (0)

Allergy or ...

Eyeworld June 2006

.....“If it itches, it is allergy; if it burns and stings, it’s dry eye; and if it’s crusty and sticky in the morning, then it’s bacterial,” Dr. Abelson said

Posted by mehdi khanlari at 11:48 AM | Comments (0)

Allergy and Omalizumab

Eyeworld June 2006

omalizumab, acts by binding to free circulating IgE. Once omalizumab binds to IgE, a complex forms between the two, which effectively inactivates IgE (Williams 2005).Omalizumab (Xolair, Novartis, Basel, Switzerland) is currently indicated for moderate to severe persistent asthma that is inadequately controlled with corticosteriods and is administered via subcutaneous injection. While this indication does not include ocular allergy, some recent studies suggest this drug may be applicable for rare, severe forms such as AKC. Omalizumab has been clinically tested in AKC patients, and in a six-subject pilot study five reduced administration of topical ocular steroid medication and experienced some degree of ocular symptom improvement. One subject experienced an adverse event of eczema exacerbation (Williams 2004). Other studies of asthmatic subjects have found reductions in ocular symptoms with omalizumab administration (Babu 2001). In the future omalizumab may present a viable alternative to the limited treatment options currently available for severe forms of ocular allergy.

Posted by mehdi khanlari at 11:07 AM | Comments (0)

May 05, 2006

Anecortave acetate might lower IOP in patients with open-angle glaucoma

INDUSTRY NEWS
A study reported at the Association for Research in Vision and Ophthalmology finds that a single subtenon injection of anecortave acetate (Retaane) could dramatically lower IOP in patients with open-angle glaucoma and eliminate their dependence on daily therapy. The study’s author said it’s unclear how the drug lowers IOP, but the results are "really impressive and kind of shocking."

Posted by kjalali at 11:18 AM | Comments (0)

An insulin sensitizer may protect diabetes patients from developing diabetic retinopathy

INDUSTRY NEWS
A study reported at the Association for Research in Vision and Ophthalmology compared the outcomes of 124 patients treated with rosiglitazone (Avandia) and 158 controls whose diabetes was treated with other agents. After a mean of 2.8 years of follow-up, visual acuity decreased by three or more lines in 2.7 percent of patients in the rosiglitazone group, compared with 6.6 percent in the control group. Overall, progression to severe non-proliferative diabetic retinopathy occurred in 7.1 percent of rosiglitazone subjects compared with 20.8 percent of controls.

Posted by kjalali at 11:16 AM | Comments (0)

Repeat, high-dose injections of triamcinolone acetonide appear well-tolerated in patients with diabetic macular edema

Ophthalmology, May 1, 2006
This non-randomized, comparative study included 19 patients who presented at a single hospital with vision loss due to diffuse diabetic macular edema. These patients were re-treated with approximately 20 mg of triamcinolone acetonide if the first intravitreal injection was associated with an improvement in vision followed by an eventual re-deterioration in visual acuity. The re-injection led to a significant (P = 0.002) re-improvement in visual acuity, with 50 percent showing an improvement in visual acuity by at least two Snellen lines during the follow-up after the second injection. The increases in visual acuity, noted after the first injection and after the second injection, lasted about six to eight months with no marked difference between the first injection and the re-injections. This is considerably longer than the duration for a dosage of 4 mg intravitreal triamcinolone acetonide (approximately two to four months) reported in other studies. The authors conclude that their findings suggest re-injection may be performed at approximately six to eight months or later after an initial injection, if the first injection was associated with an improvement in visual acuity. Similarly, a spike in IOP lasted about six to eight months after the injections, which the authors note suggests patients be followed for several months after a high-dose injection to detect a steroid-induced increase in IOP.

Posted by kjalali at 11:15 AM | Comments (0)

Timing of scleral flap suture release after glaucoma filtration surgery affects complication rates

AJO, April 2006
This retrospective chart review of 173 patients (173 eyes) with primary open-angle glaucoma who had primary phacotrabeculectomy finds that patients who underwent scleral flap suture release less than three weeks after surgery had a lower long-term success rate than patients who underwent the release procedure three weeks or more after surgery. The overall follow-up was 44.8 months. At four years, the mean complete success rate for early suture release was 15 percent; for late suture release, 22 percent. Complete success was defined as IOP less than 18 mm Hg but greater than 5 mm Hg, without the use of medication or additional glaucoma surgery. Qualified success was defined with the same IOP criteria but allowed for use of g