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August 31, 2006
FDA approves a unique tonometer
INDUSTRY NEWS
BiCOM Inc says its non-contact Diaton tonometer can measure IOP through the eyelid. The company’s press release says it requires no anesthesia or sterilization.
Posted by kjalali at 05:07 AM | Comments (0)
August 28, 2006
Topical viral conjunctivitis treatment shows promise in preclinical studies
OSN Breaking News
A topical formulation of N-chlorotaurine shows potential against viral conjunctivitis in preclinical studies, according to a press release by the drug's developers.
Jerold Gordon, MD, and colleagues , evaluated the compound using an in vitro and a rabbit model. The study involved adenovirus serotypes responsible for viral conjunctivitis.
In vitro, N-chlorotaurine showed concentration-dependent direct inactivation of all tested virus serotypes. In the rabbit model, researchers found significantly fewer positive cultures at 1 to 14 days after infection. They also noted a shorter duration of virus shedding and lower mean combined viral titers at days 7 to 14 compared to controls, according to the release.
N-chlorotaurine is being investigated by Acuity Pharmaceuticals Inc. and Pathogenics Inc. The ocular formulation is currently in a phase 1 clinical trial in Europe.
Posted by aman at 11:30 PM | Comments (0)
August 26, 2006
Intraoperative Mitomycin and Corneal Endothelium After Photorefractive Keratectomy
AJO Sep 2006
Corneal endothelium was analyzed preoperatively and postoperatively in 18 eyes of nine patients who were administered either MMC- or balanced salt solution (BSS)–supplemented PRK at Codet Aris Vision, Tijuana, Mexico. After laser ablation, one eye was randomly assigned to intraoperative topical MMC 0.02% treatment for 30 seconds, and the fellow eye (the control eye) was treated in a standard fashion with topical BSS. Preoperative pachymetry and endothelial cell count were performed and compared with postoperative measurements after one month and three months. Main outcome measure studied was endothelial cell loss.
Results
There was no significant difference in the preoperative endothelial cell count between the 2 groups: MMC group 2835 ± 395, control group 2779 ± 492, P = .62. In the control group, at one month and three months the difference in the endothelial cell count was not statistically significant (P = .27, P = .14, respectively). However, in the MMC group the endothelial cell loss was statistically significant: at one month 14.7 ± 5.1%, and at three months 18.2 ± 9.0% (P = .0006, P = .002, respectively).
Conclusions
The use of intraoperative topical MMC 0.02% for 30 seconds after PRK may affect the endothelial cell count.
Posted by aman at 11:51 PM | Comments (0)
Fluidics and Heat Generation of Alcon Infiniti and Legacy, Bausch & Lomb Millennium, and Advanced Medical Optics Sovereign Phacoemulsification Systems
AJO Sep 2006
Heat generation with continuous ultrasound was determined with and without a 200-g weight. Flow and vacuum were determined from 12 to 40-ml/min in 2-ml/min steps. The impact of a STAAR Cruise Control was also tested.
Results
Millennium created the most heat/20% of power (5.67 ± 0.51°C unweighted and 6.80 ± 0.80°C weighted), followed by Sovereign (4.59 ± 0.70°C unweighted and 5.65 ± 0.72°C weighted), Infiniti (2.79 ± 0.62°C unweighted and 3.96 ± 0.31°C weighted), and Legacy (1.99 ± 0.49°C unweighted and 4.27 ± 0.76°C weighted; P < .0001 for all comparisons between machines except Infiniti vs Legacy, both weighted). Flow studies revealed that Millennium Peristaltic was 17% less than indicated (P < .0001 to all other machines), and all other machines were within 3.5% of indicated. Cruise Control decreased flow by 4.1% (P < .0001 for same machine without it). Millennium Venturi had the greatest vacuum (81% more than the least Sovereign; P < .0001), and Cruise Control increased vacuum in a peristaltic machine 35% more than the Venturi system (P < .0001).
Conclusions
Percent power is not consistent in regard to heat generation, however, flow was accurate for all machines except Millennium Peristaltic. Restriction with Cruise Control elevates unoccluded vacuum to levels greater than the Venturi system tested.
Posted by aman at 11:36 PM | Comments (0)
Subretinal membranes are associated with abnormal degrees of pupil "evasion": an index of clinical macular dysfunction
BJO Sep 2006
To assess whether macular dysfunction caused by unilateral subretinal neovascular membranes (SRNs) is associated with pupil "evasion" (that is, increased initial rate of re-dilation following a brief light stimulus).
Comparative observational series. 20 eyes of 10 participants, all with unilateral SRNs and healthy fellow eyes. Dynamic infrared pupillography at seven stimulus intensities (duration 1100 ms, intensities over 2 log unit range). Pupil evasion ratio (PEVR; defined as the ratio of light response amplitude to amount of recovery at the mid-time point of re-dilation expressed as a percentage) was calculated for each stimulus intensity (mean of five recordings).
Results: Inter-eye PEVR is significantly reduced in eyes with SRN (that is, greater pupil evasion in SRN eyes: range p = 0.002 to p = 0.05 (paired t test)) and is most apparent at higher stimulus intensities.
Conclusions: PEVR is a novel parameter that is analogous to the pupil escape ratio, but measured following a short rather than a sustained light stimulus. PEVR is significantly altered by macular disease. Clinically PEVR may be used to detect occult unilateral or asymmetric maculopathy in situations such as ocular media opacities like cataract, when pupil reactions are unaffected or augmented, while other tests of retinal function are diminished. PEVR represents altered neuronal firing in cones and macular ganglion cells.
Posted by aman at 11:31 PM | Comments (0)
Choroidal detachment in perforated corneal ulcers: frequency and management
BJO Sep 2006
18 eyes of 17 patients were studied. Inclusion criterion was any patient with a non-traumatic perforated corneal ulcer. All patients had a thorough history taken and complete ophthalmic examination including B-scan ultrasonography. Patient demographics, presence of CD, and efficacy of corneal gluing were assessed.
Results: Eight of the 18 eyes (44%) were documented to have a CD. Among perforations of >2 mm2, six eyes (75%) were documented to have CD compared with two eyes (20%) with perforations of 2 mm2 (p = 0.054). No correlation could be determined between perforation duration and incidence of CD. Of the 15 eyes that underwent gluing, there were 13 successes (87%) and two failures (13%). Within the successes four patients (27%) required re-gluing because of infection (one patient) or progression of melt and glue loosening (three patients). Failure was the result of severe progression of melting (one patient) and a very large perforation (one patient).
Conclusion: Choroidal detachment following corneal ulcer perforation is common and is more likely in larger corneal perforations. Preoperative B-scan should be considered in cases of large corneal perforations requiring therapeutic keratoplasty to document choroidal detachment, which if large may require drainage. Cyanoacrylate glue is an effective and safe method for sealing small corneal perforations. A vigil must be maintained for infection while the glue and bandage contact lens are in situ.
Posted by aman at 11:26 PM | Comments (0)
Changes in the posterior cornea after laser in situ keratomileusis and photorefractive keratectomy
Journal of Cataract & Refractive Surgery Volume 32, Issue 9 , September 2006, Pages 1426-1431
In this prospective study, 121 consecutive myopic eyes (103 LASIK and 18 PRK) were evaluated preoperatively and postoperatively with the Pentacam to determine elevation changes in the posterior corneal surface. Changes in posterior elevation were calculated by comparing the best-fit sphere preoperatively and postoperatively to a fixed reference sphere using the central 9.0 mm preoperative cornea. Statistical and graphic analyses were performed.
Results
The 103 LASIK eyes had a mean correction of −3.76 diopters (D) and a mean ablation depth of 62.1 μm. The mean estimated residual bed thickness (RBT) (329 μm) demonstrated a mean posterior displacement of 2.64 ± 4.95 μm. The 18 PRK eyes had a mean correction of −2.69 D and a mean ablation depth of 53.2 μm. The mean estimated RBT (464 μm) had a mean posterior displacement of −0.88 ± 4.64 μm. The difference in the mean posterior corneal displacement between the LASIK and the PRK eyes was not statistically significant (P>.05, Student t test).
Conclusions
There was no statistically significant difference in posterior corneal displacement between the LASIK and PRK patients. The changes in PRK and LASIK eyes appeared to be within acceptable measurement variation. Contrary to previous reports, ectatic changes to the posterior corneal surface did not routinely occur after LASIK surgery.
Posted by mmiraftab at 08:05 PM | Comments (0)
August 25, 2006
Lilly receives approvable letter for Arxxant
INDUSTRY NEWS
In the approvable letter, the U.S. Food and Drug Administration (FDA) requests additional data to support the clinical evidence presented by Lilly in its new drug application for Arxxant, an investigational oral therapy for diabetic retinopathy.
Posted by kjalali at 07:46 PM | Comments (0)
Children with optic neuritis are at higher risk for MS than previously thought
Neurology. 2006
An evaluation of 36 children younger than 18 who were followed for two years finds that 36 percent developed multiple sclerosis. Other factors associated with development of MS: bilateral disease and white matter lesions demonstrated on cranial MRI.
Posted by kjalali at 07:42 PM | Comments (0)
Small-gauge vitrectomy possible using topical anesthetic
OSN
Raju Biju and colleagues at the Ranjini Eye Center in India applied anesthetic-soaked pledgets for 3 minutes prior to performing 25-G vitrectomy in seven patients. Postoperatively, patients were asked to rate their intraoperative discomfort level using a five-point scale, with 0 being no pain or discomfort and 4 being the most severe. All patients reported grade 0 pain during vitrectomy, although five patients reported grade 2 pain during the initial sclerectomy.
Posted by kjalali at 07:37 PM | Comments (0)
Therapy for wet AMD enters phase 1 trial
OSN
Athenagen Inc. has initiated a phase 1 clinical trial of its ATG003, an investigational topical drug for exudative age-related macular degeneration. ATG003 is a topical formulation of mecamylamine that inhibits endothelial nictonic acetylcholine receptors. It has been shown to decrease angiogenesis and vascular permeability. The randomized, placebo-controlled, ascending dose trial will evaluate ocular tolerability and safety of the compound for up to 14 days. This is the first human trial of an eye drop therapy for wet AMD.
Posted by kjalali at 07:32 PM | Comments (0)
August 22, 2006
The Course of Glaucoma During Pregnancy
ARCHIVES August 2006
Retrospective case series of 28 eyes of 15 women with glaucoma followed up during pregnancy. Data were analyzed for age, race/ethnicity, medications, glaucoma type, intraocular pressure (IOP), and visual fields before, during, and after pregnancy.
Results In 16 (57.1%) of 28 eyes, IOP was stable during pregnancy, with no progression of visual field loss. In 5 eyes (17.9%), visual field loss progressed during pregnancy, while IOP remained stable or increased. In 5 eyes (17.9%), IOP increased during pregnancy, but there was no progression of visual field loss. In 2 eyes (7.1%), data were inconclusive because of medication noncompliance and preexisting severe visual field loss. Glaucoma medications were used by 13 of 15 patients to control glaucoma during pregnancy. The classes of medications used most frequently were -blockers, 2-adrenergic agents, cholinergic agents, and topical carbonic anhydrase inhibitors.
Conclusions The course of glaucoma during pregnancy is variable, and women must be monitored closely during pregnancy. Medications may be necessary to control IOP and to prevent vision loss during pregnancy.
Posted by aman at 10:46 AM | Comments (0)
Preserved Kenalog linked to multiple cases of sterile endophthalmitis
OSN SuperSite Top Story 8/21/2006
Several cases of sterile endophthalmitis have been associated with intravitreal injection of a preserved triamcinolone acetate formulation within the past 4 months, according to a surgeon speaking here.
Since May, Dr. Eaton said, he has seen four cases of sterile endophthalmitis among 29 patients he has treated with intravitreal Kenalog injections, an incidence of 14%. In comparison, only one patient developed endophthalmitis out of 662 patients he injected with the drug from 2003 to 2005, an incidence rate of 0.15%. Dr. Eaton is an assistant clinical professor at the University of South Florida, as well as a solo practitioner specializing in retina/vitreous.
The four recent cases showed no association with age, gender or amount of inflammation; the only common factor was the use of preserved Kenalog, Dr. Eaton said. He noted that he experienced no such complications with intravitreal injection of other medications.
Additionally, he said, in speaking with other surgeons, he learned that his were not the only cases. Surgeons at Bascom Palmer Eye Institute, for instance, told Dr. Eaton they had experienced nine to 11 such cases, and surgeons as far away as California have reported cases to him as well.
Posted by aman at 10:42 AM | Comments (0)
August 20, 2006
Toric phakic IOL an option in keratoconus
OSN Breaking News
The toric version of STAAR Surgical Co.'s Visian ICL, currently in U.S. clinical trials, is showing potential for treating patients with myopic astigmatism, and it may also have applications for some patients with keratoconus, according to a surgeon speaking here.
John A. Vukich, MD, discussed phakic IOLs during a presentation at the American Society of Cataract and Refractive Surgery Summer Refractive Congress. He said early clinical results with the Visian Toric ICL (TICL) show good results at 1 year.
The Visian TICL may also have potential as a treatment for patients with stable keratoconus, he suggested. In a study of 19 eyes of 15 patients with keratoconus, researchers found that best-corrected visual acuity improved following implantation of the lens.
Preoperatively, spherical equivalent was -2 D to -6 D in 36.8% of eyes, -6.1 D to -10 D in 42.1% of eyes, -10.1 D to -14 D in 10.5%, and -14.1 D to -19 D in 10.5%. Postoperatively, 44% of patients gained one line of Snellen visual acuity, 19% gained two lines, and 31% had no loss or gain of BCVA.
Posted by aman at 12:05 AM | Comments (0)
August 19, 2006
Trabeculectomy versus tube-shunt
EYE WORLD August 2006
A recent study—the Trabeculectomy versus Tube (TVT) study—sheds some light on this important matter.
“The purpose of the TVT study was to compare the safety and efficacy of non-valved tube-shunt surgery with trabeculectomy with mitomycin-C in patients with previous anterior segment surgery,” said Steven Gedde,
The trabeculectomy group had a significantly lower IOP than the tube-shunt group during the first three months post-operatively, but at six to twelve months post-op, there was no difference in mean IOP between the two groups,” Dr. Gedde said. There was less need for supplemental medical therapy by the trabeculectomy group compared with the tube group.
In addition to mean IOP changes, the group defined surgical failure as meeting one of four criteria:
• IOP above 21 mm Hg or not decreased by at least 20% from baseline
• IOP of 5 mm Hg or lower on two consecutive visits after month 3
• The need for additional glaucoma surgery
Loss of light perception vision
By these criteria, there was a significantly higher failure rate in the tube group compared with the trabeculectomy group at one year. When a post-hoc analysis was performed using more stringent IOP criteria to define success and failure, the failure rate still remained significantly higher in the trabeculectomy group.
Posted by aman at 11:53 PM | Comments (0)
Spherical aberration and contrast sensitivity after cataract surgery with the Tecnis Z9000 intraocular lens.
JCRS August 2006
In this intraindividual prospective randomized study, investigators set out to see if contrast sensitivity could be improved with cataract surgery with use of a lens such as the Tecnis Z9000 (AMO, Santa Ana, Calif.), with its modified prolate anterior surface. The 60 patients in the study were randomized to receive the Tecnis IOL in one eye and a spherical IOL in the other. The two spherical lenses used here were the AR40 E (AMO, Santa Ana, Calif.) and the Stabibag (Ioltech, S.A., La Rochelle Cedex, France). They found that eyes with the Tecnis z9000 IOL had significantly less spherical aberration. In addition, these eyes had a greater Strehl ratio after surgery and in some cases also showed a significant reduction in coma. However, there were no significant differences between the three IOLs when it came to refraction, visual acuity, and contrast sensitivity. Investigators concluded that while the Tecnis z9000 significantly reduced spherical aberration, visual acuity and contrast sensitivity fared the same as with a spherical IOL.
Posted by aman at 11:43 PM | Comments (0)
SLT Technique
SHIELDS TEXTBOOK
A new laser procedure using a frequency-doubled Q-switched 532-nm
Nd:YAG laser ( SLT) has been designed to lower IOP in patients with
COAG.
The neodemium atoms are embedded in a crystal of YAG AND ARE PUMPED BY
a xenon flash lamp.The laser wavelength is in the near infrared (1,064-nm) range,although it can be made a visible light emmited by frequency doubling or an U.V emitter by frequency tripling.
Nd:YAG laser can be operated in the CW mode to provide a photocouagulation effect,but are more commonly used with puled delivery,using either Q-switching or mode -locking, to allow photo-
disruption.
SLT is potentially repetable procedure because of the lack of couagulation damage to the T.M and the efficacy in patients with ALT.
A total of 50 to 60 adjacent, non over laping spots are placed over 180 degrees of the T.M with energy ranging from 0.5 to 1.2 mJ per-pulse, set to prevent bubble formation.
Transient IOP elevation of 5 to 6 mm Hg was seen in 25% of patients.
Elevation more than 10 mmHg was seen in some patients.
The IOP reduction after SLT ranged frome 3 to 18 mmHg six months after 180 degrees SLT,mean reduction was 4.4 mmHg, with the success rate of 64.6%.
A low preoperative IOP was the significant determinant for success,while age,gender,past history of ALT,and T.M pigmentation
were not significantly related to success.
when the T.M was treated 360 degrees ,the IOP was reduced 40% 6 WEEKS
after the treatment.
Posted by aman at 10:40 PM | Comments (0)
August 18, 2006
MacuSight to begin clinical trials for a new drug to treat wet AMD and diabetic macular edema
INDUSTRY NEWS
The U.S. Food and Drug Administration has accepted the company’s Investigational New Drug application for sirolimus (rapamycin), a compound capable of multiple mechanisms of action, including immunosuppressive, anti-angiogenic, anti- migratory, anti-proliferative, anti-fibrotic and anti-permeability activity.
Posted by kjalali at 07:07 AM | Comments (0)
Lutein and zeaxanthin linked to reduced risk of AMD in women
Archives of Ophthalmology, August 2006
This ancillary study of the Women's Health Initiative finds a diet rich in carotenoids was associated with a lower risk of intermediate-stage AMD in healthy women younger than 75. The association with advanced-stage AMD in the overall sample and in women younger than 75 was statistically insignificant.
Posted by kjalali at 07:05 AM | Comments (0)
August 16, 2006
SLT EFFICACY
GLAUCOMA TODAY
Prospective studies have shown that SLT as primary
therapy can decrease IOP by 30% to 35%,6,7 similar to the
reduction in pressure achieved with the most effective,
current topical medications. After SLT, however, no compliance
on the part of the patient is required to continue
the treatment’s efficacy or prevent complications. At the
7-year follow-up in the Glaucoma Laser Trial,8 subjects
who first underwent treatment with an argon laser versus
medication had a slightly lower IOP, and the status of
their visual fields and optic nerve was somewhat better.
Although a number of the laser-first patients eventually
required medication to maintain control of their IOP, by
the end of follow-up, these individuals achieved a 38%
reduction in the total number of days requiring medication
compared with subjects first treated with medical
therapy. In all, undergoing initial treatment with a laser
versus medication reduced subjects’ dependence on drug
therapy. In light of the issues with compliance outlined
earlier, these results favor the use of laser therapy earlier in
the course of glaucoma treatment.
Posted by aman at 12:37 AM | Comments (0)
SLT Mechanism of Action
GLAUCOMA TODAY
ALT causes thermal coagulative damage to the trabecular
meshwork. Electron microscopy shows the procedure disrupts
the trabecular beams and significantly harms adjacent
tissue. SLT’s effect on the trabecular meshwork appears to
be different.6 Its selective photothermolysis uses an ultrashort
laser pulse to generate and confine heat at explicit pigmented
targets—the melanin contained in the trabecular
meshwork’s cells. The laser pulse’s short duration (3 nanoseconds)
minimizes the associated heat of the laser shot and
thus prevents collateral damage, because the pulse time is
shorter than the thermal relaxation time of melanin (1 microsecond).
Electron microscopy of trabecular meshwork
treated by SLT shows none of the disruption seen with ALT.7
Some researchers have hypothesized that ALT works in
part by mechanically changing the meshwork (ie, laserinduced
microscars reverse the pathologic laxity and collapse
of trabecular tissues8). Both ALT and SLT are hypothesized
to increase drainage through the trabecular meshwork
by releasing chemotactic factors such as interleukin-1a,
interleukin-1b, and tumor necrosis factor-alpha. The resultant
recruitment of macrophages affects aqueous outflow
facility and thus lowers the IOP.
The key difference between the procedures is the apparent
absence of significant coagulative damage to the meshwork
in SLT-treated eyes. Also, SLT can have a crossover
effect, in which the IOP of the untreated eye decreases after
its fellow undergoes the procedure. This observation argues
for a totally biological rather than mechanical mechanism of
action in SLT. One might hypothesize that activated macrophages
collect in the spleen and are then released into the
blood stream, where some act upon the contralateral trabecular
meshwork.6 SLT’s ostensible stimulationof this system
without the destructive collateral thermal damage seen
in ALT is probably the basis for the procedure’s potential
repeatability.
Posted by aman at 12:30 AM | Comments (0)
August 15, 2006
Glaucoma Therapy: Compliance, Adherence, Persistence, and Alliance
GLAUCOMA TODAY AUGUST 2006
Compliance is often defined as how well patients follow physicians’ recommendations. Recently, this term has acquired a negative meaning that suggests we physicians decide which medications patients should use and patients passively use them as prescribed.
Recently, clinicians have substituted the less judgmental word adherence for compliance in glaucoma therapy.1,2 The former term implies that patients have some control over how they use their medications and that they will use them willingly, either because they have an understanding of their disease or because they simply believe treatment is appropriate. For instance, patients with type A personalities may be more likely to adhere to a medical regimen if they believe it is important to prevent glaucoma from damaging their vision. Adherence also acknowledges that patients must overcome real barriers, such as restrictions imposed by insurance companies’ preferred formularies, to use their glaucoma medicine effectively.
Another way to track compliance is by measuring persistence (eg, how long patients use their glaucoma eye drops regularly without periodic discontinuation). Persistence with glaucoma medications is generally considered to be poor, with studies reporting that fewer than 25% of patients use their eye drops continuously for 12 months.3 Individual patients’ persistence may also fluctuate over time.
Alliance is the ultimate form of compliance. The word suggests that patients, physicians, family members, and everyone else involved in the management of an individual’s glaucoma collaborate to ensure the proper use of medication.
Posted by aman at 11:57 PM | Comments (0)
Small study shows immediate benefit from intracorneal presbyopia implant
OSN SuperSite Breaking News 8/9/2006
Francisco Sánchez León, MD, conducted an informal study involving 14 presbyopic patients implanted with the Invue intracorneal implant (Biovision). He presented the results at the Mexican Congress of Ophthalmology.
The Invue is implanted through an intracorneal tunnel ranging from 220 to 250 µm deep. It is inserted using a specially designed injector and centered with a cannula, Dr. Sánchez León said.
Preoperatively, near visual acuities ranged from 20/40 to 20/200, including four patients who were 20/100. At 1-week follow-up, six patients achieved 20/20 uncorrected near vision. At 6 months, eight patients achieved 20/20 uncorrected near vision, and three patients achieved 20/25, Dr. Sánchez León said.
“There is no learning curve, and one of the major elements of the technique is its reversibility,” he said
Posted by aman at 11:50 PM | Comments (0)
August 13, 2006
Endothelial cell counts decrease following phakic IOL implantation
OSN SuperSite Breaking News 8/9/2006
GUADALAJARA, Mexico ? Despite good visual results, endothelial cell loss remains an issue following phakic IOL implantation, according to a surgeon speaking here.Beatriz Martz Blas, MD, and colleagues compared rates of endothelial cell loss between 48 eyes of 27 myopic patients implanted with the Artisan phakic IOL (Ophtec) and a control group of 44 non-implanted eyes of 25 myopic patients.Dr. Martz Blas presented the results at the Mexican Congress of Ophthalmology.Preoperative myopia ranged from 9 D to 26 D in phakic IOL-implanted eyes and from 7 D to 26 D in control eyes.The researchers found that mean endothelial cell counts in implanted eyes decreased 13% from 2551.04 at preop to 2222.2 at 12 months follow-up. In contrast, endothelial cell counts in control eyes decreased only 2% from 2561.61 at preop to 2504.36 at follow-up, Dr. Martz Blas said."Implantation of the Artisan lens for the correction of myopia is one more alternative. However, the loss of corneal endothelial cells is evident. For this reason, continued monitoring is necessary in order to confirm the long-term impact," she said.The Artisan phakic IOL is marketed in North America by Advanced Medical Optics under the brand name Verisyse.
Posted by mehdi khanlari at 11:53 PM | Comments (0)
Numerous risk factors for corneal ectasia
OSN SuperSite Breaking News 8/11/2006
BOSTON — Chronic trauma induced by eye rubbing may be an important potential risk factor for corneal ectasia, according to a surgeon speaking here.R. Doyle Stulting, MD, PhD, spoke about corneal ectasia and its risk factors in a keynote presentation here at the American Society of Cataract and Refractive Surgery Summer Refractive Congress.
According to Dr. Stulting, both a family history and premature birth could increase patients’ risks. Other probable risk factors include eye rubbing, increased astigmatism and biomechanical instability, while possible risk factors include keratocyte abnormality and the use of mitomycin-C.“Don’t ignore red flags, especially when there are more than one,” he said. “Some patients will develop ectasia even with normal topographies, even after PRK.”
Dr. Stulting and colleagues at Emory University, Atlanta, recently studied 27 eyes of 25 patients with a mean age of 27.8 years. The researchers had carefully selected patients who had the fewest ectasia risk factors possible. All patients underwent PRK, with a mean predicted ablation depth of 85.3 µm, according to Dr. Stulting.
The researchers found it took an average of 14.8 months following surgery to recognize the onset of ectasia. Also, the estimated incidence was about 1 in 2,500 cases, but that data could be an under- or overestimate, Dr. Stulting said.
Posted by mehdi khanlari at 11:53 PM | Comments (0)
Foreign body extractor allows safe, effective removal in traumatized eyes
OSN SuperSite Breaking News 7/5/2006
ROME — A simple device can safely and effectively remove larger intraocular foreign bodies with minimally traumatic maneuvers.The instrument, developed by Claus Eckardt, MD, is a modification of the Erakgün snare. The device has a tubular handpiece with a retractable wire snare made of a metallic alloy that is capable of returning to its initial form after being bent. Once the instrument is inserted in the globe, the snare is pushed out. The loop is kept fairly large to surround the foreign body, and is then tightened around the foreign body to firmly grasp and withdraw it from the eye. With this instrument, intraocular foreign bodies of different sizes and shapes can be removed easily, said one speaker here. “The loop of the extractor comes out at an angle of 80°, and is able to hold and remove long objects almost vertically, along the axis of the instrument,” said Tillmann Eckert, MD, at the International Society of Ocular Trauma meeting.“If additional maneuvers are needed, the extractor can be used like a spoon within the vitreous cavity to disengage and place the foreign body in the best position to capture it,” Dr. Eckert added
Posted by mehdi khanlari at 11:44 PM | Comments (0)
Droperidol reduces perforating keratoplasty complications
OSN SuperSite Breaking News 7/10/2006
Droperidol can reduce intraoperative and postoperative complications in patients undergoing penetrating keratoplasty, according to a study.
Hanna J. Garzozi, MD, and colleagues randomly assigned 27 patients undergoing penetrating keratoplasty to two groups. Fifteen patients were given droperidol during the induction of general anesthesia. The remaining 12 patients received general anesthesia without droperidolFor the group that received droperidol, IOP was significantly reduced in the fellow eye, and intraoperative chamber depth was significantly deeper. Also, none of the patients who received droperidol had iris bulging, compared with 25% in the control group. Those who received droperidol also reported less postoperative nausea and postop vomiting.This study was published in Ophthalmologica.
Posted by mehdi khanlari at 11:41 PM | Comments (0)
Placido-based corneal topography outdated, limited in scope
OSN SuperSite Breaking News 8/11/2006
BOSTON — Current placido-based corneal topography systems assume all corneas conform to a known conic section, not allowing for a more true shape representation, according to a surgeon speaking here.In a keynote presentation at the American Society of Cataract and Refractive Surgery Summer Refractive Congress, Michael W. Belin, MD, discussed issues surrounding corneal topography. He said topographic analyses based only on placido-derived anterior curvature are incomplete; they show the corneal apex, line of sight and VK axis as the same.He noted that in a study involving Bausch & Lomb’s Orbscan, the device incorrectly read the corneal thickness of one patient as being 37 µm thinner. It also showed an incorrect ectasia.“It is like relying on an X-ray when a MRI is available,” Dr. Belin said.In comparison, elevation data is independent of axis, orientation or positioning, according to Dr. Belin. He said all further maps of curvature can be derived from accurate elevation data.“Keratoconus screening requires the use of topography systems that measure elevation data as their elemental requirement,” he said
Posted by mehdi khanlari at 11:41 PM | Comments (0)
Prolonged hard contact lens wear may cause Mueller muscle fibrosis
OSN SuperSite Breaking News 7/14/2006
Blepharoptosis as a result of prolonged hard contact lens wear may be due to structural changes in Mueller muscle, according to one study.Additionally, blepharoptosis may not just be caused by aponeurogenic changes from the repeated removal of the hard lenses. Furthermore, fatty degeneration of the levator aponeurosis and Mueller muscle may be involved in the development of involutional blepharoptosis.According to the authors, age was not a factor in the presence of fibrosis in Mueller muscle in patients with hard contact lens-induced blepharoptosis.The study is published in the American Journal of Ophthalmology
Posted by mehdi khanlari at 11:35 PM | Comments (0)
Eyelid pressure can alter corneal topography
OSN SuperSite Breaking News 7/25/2006
When the eyes look down or move laterally, eyelid pressure can alter corneal topography, a study shows.Michael J. Collins, PhD, and colleagues studied the effects of eyelid pressure on corneal topography for different angles of gaze and eye movement conditions among 10 young people with healthy eyes. They measured the corneal topography of the right eye with a videokeratoscope before and after 15-minute visual tasks of downward gaze at 25° and 45°, both performed with either no eye movements or eye movements of 1 Hz. They conducted the four tasks on four separate mornings, according to the study Researchers found that the people studied showed significant regions of topographic change after the four tasks. “In general, eye movements were found to cause greater topographic changes than tasks without eye movements, and the larger angle of downward gaze led to greater changes in topography,” they said. “The topographic changes were located close to the lid margin position during each task The study is published in the July issue of Eye & Contact Lens.
Posted by mehdi khanlari at 11:29 PM | Comments (0)
Protein found to prevent corneal blood vessel growth
OSN SuperSite Breaking News 7/20/2006
Large amounts of the protein VEGFR-3 on the epithelial layer of the cornea inhibit neovascularization and allow the cornea to remain clear, Boston researchers found.In an experimental study involving mice, Reza Dana, MD, and colleagues at the Schepens Eye Research Institute and the Massachusetts Eye and Ear Infirmary discovered that VEFGR-3 (vascular endothelial growth factor receptor-3) and the gene that expresses it were present on the corneal epithelium. They also found that only corneas without epithelial layers developed new blood vessels, implicating the epithelium’s role in suppressing blood vessel growth.In a series of studies, the researchers found that adding a VEGFR-3 substitute to corneas that were stripped of their epithelial layers prevented blood vessel growth. Additionally, intact corneas exposed to a VEGFR-3-blocking agent began to experience blood vessel growth.The study was published in the July 25 issue of the Proceedings of the National Academy of Sciences.
Posted by mehdi khanlari at 11:29 PM | Comments (0)
Secondary glaucoma common in Acanthamoeba keratitis patients
OSN SuperSite Top Story 7/28/2006
Patients with Acanthamoeba keratitis frequently develop secondary glaucoma, a retrospective study found. Additionally, such patients often need surgery to control IOP and preserve vision, the study indicated.“The development of secondary glaucoma is not uncommon in Acanthamoeba keratitis and is a poor prognostic sign ... because most [eyes] progress to light perception or no light perception vision,” the authors said in the study.Histopathologic examinations identified chronic trabecular meshwork inflammation as well as angle closure. However, no Acanthamoeba organisms were present in any angle structures, which suggests “an inflammatory angle-closure mechanism, apparently without direct infiltration of the organism,” the authors said.The study was published in the July issue of Eye & Contact Lens.
Posted by mehdi khanlari at 11:28 PM | Comments (0)
Cornea guttata more prevalent in women and smokers
OCULAR SURGERY NEWS EUROPE/ASIA-PACIFIC EDITION August 2006
Using non-contact specular microscopy allowed researchers to make the connection and analyze related cell density.People who have smoked for more than 20 pack-years have a more than twofold increase of developing cornea guttata than those who never smoked, according to one study. In addition, women have a higher prevalence of the disease than men, researchers of a large population-based study found.Although they do not know the exact mechanism that links smoking with development of cornea guttata, Dr. Jonasson said it is likely due to oxidative damage, as is believed to be the case with smoking and other eye diseases.
Posted by mehdi khanlari at 11:19 PM | Comments (0)
Simultaneous bilateral cataract surgery: Financial differences among nations and jurisdictions
JCRS Pages 1355-1360 (August 2006)
35 of 43
Arshinoff -Canada.To identify and measure financial pressures surrounding unilateral and simultaneous bilateral cataract surgery in Canada and other Western nations to understand financial factors that may affect simultaneous bilateral cataract surgery.
Methods
Schedules of physician benefits from 4 Canadian provinces and public and private sectors in the United States were applied to a consistent template for unilateral and simultaneous bilateral cataract surgery. Well-known surgeons from the United Kingdom, Australia, Japan, and Israel provided additional information. The data were analyzed for similarities and differences to identify financial factors that may influence surgeons and anesthesiologists regarding simultaneous bilateral cataract surgery.
Results
Simultaneous bilateral cataract surgery yielded approximately 15% greater efficiency in the number of daily operations. Ophthalmologists' surgical fees were variably discounted for the second cataract surgery, up to 100% in some jurisdictions. Financial incentive issues were compounded by widely differing reimbursement schemes across regions. Anesthesiologists were generally reimbursed for simultaneous bilateral cataract surgery through additional time units of pay, not for additional surgical complexity. Simultaneous bilateral cataract surgery led to greater administrative, laboratory, and nursing efficiencies for institutions with minimal increases in overall complexity.
Conclusions
Results show that discounting second-eye cataract surgery in simultaneous bilateral cataract surgery was a financial deterrent. Although increased efficiency was a slight incentive to ophthalmologists and surgical centers, anesthesiologists experienced significant financial disincentives.
Posted by alireza habibollahi at 10:45 PM | Comments (0)
Phacoemulsification with topical anesthesia: Resident experience
JCRS Pages 1361-1365 (August 2006)
36 of 43
To compare the intraoperative and postoperative complications and outcomes of phacoemulsification performed by residents using topical and retrobulbar anesthesia.
One hundred fifty phacoemulsification procedures were performed by 3 residents who used retrobulbar anesthesia (retrobulbar group), and 146 phacoemulsification procedures were performed by another 3 residents who used topical anesthesia and who had no experience with retrobulbar or peribulbar anesthesia (topical group). Case notes were prospectively compared. The data analyzed included the ocular history, intraoperative and postoperative complications, and final best spectacle-corrected visual acuity (BSCVA).
Results
There were no differences between the 2 groups in complication rates. Anterior capsule tears occurred in 8 eyes (5.3%) in the retrobulbar group and 7 eyes (4.7%) in topical group. Capsulorhexis was continuous but not curvilinear in 14 eyes (9.3%) and 12 eyes (8.2%), respectively. Capsulorhexis tear or posterior capsule rupture that necessitated conversion to extracapsular cataract extraction occurred in 3 eyes (2.0%) in the retrobulbar group and in 1 eye (0.6%) in the topical group. Posterior capsule rupture with vitreous loss occurred in 10 eyes (6.6%) and 9 eyes (6.1%), respectively. Loss of lens fragments in the vitreous cavity occurred in 3 eyes (2.0%) and 4 eyes (2.7%), respectively. The 63 postoperative complications (41 eyes [27.3%], retrobulbar group; 22 eyes [15.0%], topical group) included cystoid macular edema, intraocular lens decentration, endophthalmitis, bullous keratopathy, transient intraocular pressure elevation, temporary corneal edema, and vitreous hemorrhage. Some cases had more than 1 complication. The BSCVA, including in eyes with preexisting ocular pathology, was 20/40 or better in 86.7% in the retrobulbar group and 84.9% in the topical group.
Conclusion
When supervised and in selected patients, residents who have no retrobulbar or peribulbar anesthesia experience can safely perform phacoemulsification using topical anesthesia.
Posted by alireza habibollahi at 10:41 PM | Comments (0)
Prevalence and clinical findings of tamsulosin-associated intraoperative floppy-iris syndrome
Results
Of the 2390 cataract procedures performed, 15 patients (17 eyes) were taking tamsulosin. Five eyes (30%) displayed all 3 characteristics of IFIS, 6 (35%) displayed some of the characteristics, and 6 (35%) did not display any IFIS feature. Adjustment in the surgical technique was necessary in 2 eyes. One case had zonular dehiscence.
Conclusions
The prevalence of tamsulosin intake was lower in this study's English population than that reported in the U.S. literature. The duration of tamsulosin intake did not appear to correlate with the severity of IFIS, and the overall complication rate was low.
Posted by alireza habibollahi at 10:32 PM | Comments (0)
Anterior chamber depth measurements in phakic and pseudophakic eyes: Pentacam versus ultrasound device
JCRS Pages 1331-1335 (August 2006)
To compare anterior chamber depth (ACD) measurements with a new optical device with those taken with a standard ultrasound (US) device in emmetropic phakic and pseudophakic eyes.
Forty-two phakic and 42 pseudophakic patients with normal axial lengths (mean 22.91 mm ± 1.21 [SD]) were enrolled in the study. The ACD was measured 3 times with Scheimpflug-based Pentacam (Oculus) and then 3 times with a standard A-scan US device (AL-2000, Tomey). The data were then analyzed.
Conclusions
In phakic eyes, ACD measured with the Pentacam and with US was the same. However, in pseudophakic eyes, the difference was significantly lower when the ACD was measured with the Pentacam. Therefore, in pseudophakic patients, further evaluation of ACD data with the Scheimpflug-based system is necessary.
Posted by alireza habibollahi at 10:27 PM | Comments (0)
Spherical aberration and contrast sensitivity after cataract surgery with the Tecnis Z9000 intraocular lens
JCRS Pages 1320-1327 (August 2006)
ABSTRACT
To determine whether implantation of an intraocular lens (IOL) with a modified prolate anterior surface (Tecnis Z9000, AMO) results in reduced spherical aberration and improved contrast sensitivity after cataract surgery.
Spain,In an intraindividual randomized prospective study of 30 patients with bilateral cataract, the Tecnis Z9000 IOL was compared with 2 IOLs with spherical surfaces, the AR40e (AMO) and the Stabibag (Ioltech). Ocular aberrations for a 4.0 mm pupil and 6.0 mm pupil were measured with a Hartmann-Shack aberrometer. Quality of vision was measured by visual acuity and contrast sensitivity under mesopic and photopic conditions.
Results
Eyes with the Tecnis Z9000 IOL had significantly less spherical aberration and a greater Strehl ratio after surgery. Significant reduction in coma aberration was also found in some cases. Refraction, visual acuity, and contrast sensitivity were not significantly different between the 3 IOL groups.
Conclusion
A significant reduction in spherical aberration after Tecnis Z9000 IOL implantation was achieved, but visual acuity and contrast sensitivity were not affected by the aspheric silicone IOL compared to spherical acrylic IOLs
Posted by alireza habibollahi at 10:24 PM | Comments (0)
August 11, 2006
Changing definition of CME
OCULAR SURGERY NEWS U.S. EDITION MONOGRAPH June 15, 2006
As a result of these higher standards, the definition of CME has changed over the past several years. In the days of extracapsular surgery, CME was defined as a reduction in visual acuity to 20/40 or less due to macular leakage. In 2006, any reduction in visual function, including loss of contrast sensitivity, even if visual acuity is maintained, that results from a thickening of the macula is considered CME. The risk for CME increases in certain patients, including those with diabetes, vascular occlusion, uveitis, pre-existing CME in the nonsurgical eye, previous ocular surgery in the surgical eye and macular pucker. But whether the more encompassing definition of CME makes it a concern in patients without high-risk factors is yet to be determined
Posted by mehdi khanlari at 11:37 PM | Comments (0)
New aspheric IOL features pre-loaded injection system
OSN SuperSite Breaking News 6/20/2006
SINGAPORE — STAAR Surgical recently launched the KS-3Ai aspheric IOL, which features a pre-loaded injection system, according to a Hans Blickensdoerfer, vice president of marketing for STAAR Surgical. While the injection system provides a sterile delivery, the aspheric IOL features polyimide haptics, which help to provide stable centration and to avoid malpositioning of the lens, according to the spokesman. The news system was launched here at the Asia-Pacific Academy of OphthalmologyThe lens and pre-loaded injection system have been available in Japan for more than a year, and are now available throughout the Asia-Pacific region. They were also recently launched in Europe, company officials said.
Posted by mehdi khanlari at 11:34 PM | Comments (0)
Statins may be linked with reduced nuclear cataract risk
OSN SuperSite Top Story 6/22/2006
Statin use may be associated with a lower risk of nuclear cataract, according to a large population-based study.Barbara E. K. Klein, MD, MPH, and colleagues analyzed data from 1,299 people already enrolled in the Beaver Dam Eye Study, a longitudinal population-based study of age-related eye disease. This group of participants was seen at their third exam between 1998 and 2000, had gradable photographs in both eyes and was deemed to be at risk of developing a nuclear cataract within 5 years. Cataracts were graded from photographs taken through the participant’s dilated pupilA total of 210 people developed incident nuclear cataract in the interval from the third exam through 2003-2005. The overall 5-year incidence of nuclear cataract was 12.2% in people who used statins to control cholesterol and 17.2% in people who were not on statin therapy.The authors said the 5-year incidence of cortical cataract was 9.9% in the statin users’ group and 7.5% in the statin-free group. Posterior subcapsular cataracts occurred in 3% of the statin group and in 3.4% of the non-statin groupThe study is published in the June issue of Journal of the American Medical Association.
Posted by mehdi khanlari at 11:33 PM | Comments (0)
Dual-optic accommodating IOL granted CE mark
OSN SuperSite Breaking News 6/27/2006
IRVINE, Calif. — The Synchrony, a dual-optic accommodating IOL, has received a CE mark from European authorities, according to the device’s manufacturer.The Synchrony lens “is the first dual-optic accommodating lens developed for both cataract and refractive surgery. It is designed to enable accommodation in patients undergoing cataract surgery who may or may not have a presbyopic condition,” Visiogen, the lens’s manufacturer, said in a press release.The Synchrony incorporates the dual-optic lens, with a proprietary preloaded injector. The “system” is self-contained, Visiogen said. The lens can be inserted through a 3.6-mm to 3.8-mm clear corneal incision. The lens unfolds in the eye and “features two optics connected by a spring system,” the company said. The springs connect a 5.5-mm high-power anterior optic and a 6-mm negative power posterior optic. The spring action moves the front optic and changes the eye’s focus from near to far, the release said. To date, the lens has been implanted in more than 300 patients in seven countries. The lens is in trials in the United States, the release said
Posted by mehdi khanlari at 11:31 PM | Comments (0)
Neodymium:YAG Laser Peripheral Iridotomy: Cause of a Visually Incapacitating Cataract?
OPHTHALMIC SURGERY, LASERS & IMAGING 2006; 37(4):330
Neodymium:YAG (Nd:YAG) laser peripheral iridotomy is the procedure of choice to treat and avoid further episodes of angle-closure glaucoma. A patient who developed a visually incapacitating posterior subcapsular lens opacity shortly after Nd:YAG laser peripheral iridotomy is described. The patient underwent cataract surgery and achieved a good level of visual acuity postoperatively. The intraocular pressure remained under control with no medical treatment. This case suggests a possible, albeit rare, potential complication of Nd:YAG laser peripheral iridotomy. [Ophthalmic Surg Lasers Imaging 2006;37:330-332.]
Posted by mehdi khanlari at 11:07 PM | Comments (0)
Implantable Miniature Telescope not recommended for approval
OSN SuperSite Breaking News 7/20/2006
The Food and Drug Administration’s ophthalmic devices advisory panel voted 10-3 not to recommend for approval VisionCare Ophthalmic Technology’s Implantable Miniature Telescope.The panel found that “the data did not provide reasonable assurance that the device is safe and effective under the conditions of use prescribed, recommended, or suggested in the proposed labeling,” according to a summary of the July 14 meeting.The Implantable Miniature Telescope (IMT) is intended for adult patients with bilateral, stable, untreatable moderate to profound central vision loss due to macular degeneration or Stargardt’s macular dystrophy.The IMT is a micro-sized precision telescope that is implanted in one eye in an outpatient surgical procedure conducted under local anesthesia. The device provides magnification of 3.0X or 2.2X, varying by model.The advisory committee based its decision on unresolved safety concerns, as well as uncertainty regarding device efficacy. “The panel noted that the absence of morphometric analysis of the endothelial cell density data did not allow to adequately evaluate the chronic rate of endothelial cell density loss, a major safety concern for the device, in eyes that had received the IMT. In addition, the panel noted confounding factors that may have influenced the efficacy of the device,” according to the summary.The device’s manufacturer had conducted a prospective, multicenter trial involving 218 consecutive patients enrolled at 28 sites. The study’s primary safety endpoint was a mean loss of endothelial cell density of less than 17% at one year postoperatively. Also, no more than 10% of eyes could lose more than 2 lines of either near or distance best corrected visual acuity (BCVA) without a corresponding 2 or more gain in BCVA.However, at 1 year follow-up, mean endothelial cell density had decreased 25.3% in IMT-implanted eyes, although 90.1% of eyes had improved at least 2 lines in either near or distance best corrected visual acuity, according to the summary.
Posted by mehdi khanlari at 10:42 PM | Comments (0)
Yellow-tinted lenses offer same visual function as non-tinted
OSN SuperSite Breaking News 7/24/2006
IOLsPatients receiving yellow-tinted IOLs can be assured their visual acuity will be “virtually the same” as patients without tinted lenses, according to one study.Ken Hayashi, MD, compared 74 patients who received either short wavelength, blue light blocking, yellow tinted IOLs or traditional non-tinted IOLs in both eyes. The researchers measured eyes for contrast visual acuity with and without glare source under photopic and mesopic conditions at 2 weeks and 3 months postop.“No significant differences between the yellow tinted and non-tinted IOL groups were observed in mean visual acuity or in photopic or higher luminance mesopic contrast visual acuity with and without glare source,”He added that the incidence of patients who noticed cyanopsia in the yellow-tinted group was significantly less than those who noticed it in the non-tinted IOL group 2 weeks after surgery. No patients in either group reported cyanopsia at 3 months, according to the study.\The study was published in the British Journal of Ophthalmology.
Posted by mehdi khanlari at 10:41 PM | Comments (0)
Rheopheresis may be useful in some patients with dry AMD
OSN August 2006
Visual acuity in some patients with dry age-related macular degeneration was “statistically significantly improved” after undergoing rheopheresis treatment, said David S. Boyer, MD. He presented final results from the Multicenter Investigation of Rheopheresis for AMD, or MIRA studyRheopheresis is the elimination of rheologically relevant high molecular plasma proteins from the eye, Dr. Boyer said. The treatment is approved for use in Germany and is currently being investigated there as a treatment for drusen, mild pigment distribution or initial atrophy.Calling the study the “largest masked apheresis trial ever done,” Dr. Boyer said 121 patients, ranging in age from 50 to 85 years with a baseline visual acuity of 20/32 to 20/125, were enrolled.After 12 months, 47% of patients in the treated group gained one line compared with 18% in the control group. Dr. Boyer said 10% of the treated group lost one line of vision compared with 24% in the control group.“The mechanism of action is unknown, Dr. Boyer said. It may modify the diffusion characteristics of Bruchs membrane.There was a low incidence of serious adverse events, Dr. Boyer said, with only a 1.6% dropout rate
Posted by mehdi khanlari at 10:34 PM | Comments (0)
Trabeculoplasty works best in combination surgeries
OSN August 2006
Excimer laser trabeculoplasty gives the best results when combined with other surgeries such as cataract“Excimer laser trabeculoplasty is my favorite type of laser,” said Jens Funk, MD. “Slowly but surely, I am starting to believe in this methodAccording to Dr. Funk, 2-year follow-up in patients who had undergone the surgery showed a mean patient pressure of 21 mm Hg after surgery. Combined therapy had an 80% success rate, which was much higher when compared with treatments for high IOP alone, “Indications for combined surgery are quite generous,” Dr. Funk said when comparing excimer laser trabeculoplasty to argon laser or selective laser trabeculoplasty, advantages to the excimer laser treatment include that it is minimally invasive, it leaves no conjunctival scar, and it takes less than 2 minutes to perform. Other advantages include a combined laser and endoscope and a laser filter of 3 mm to 4 mm in diameter,The laser can be inserted across the anterior chamber and is placed into the iridocorneal angle where small holes are placed in the trabecular meshwork.
Posted by mehdi khanlari at 10:32 PM | Comments (0)
Levofloxacin effective after 5 days for conjunctivitis
OSN August 2006
Most conjunctival infections are effectively treated after a 5-day cycle of levofloxacin, according to a poster presentation.Ariadna Gierek-Lapinska, MD, and colleagues studied 69 eyes of 69 patients with bacterial conjunctivitis who were treated with 0.5% levofloxacin. Mean patient age was 43.2 years, and the patients ranged in age from 18 to 79. Success was defined as the percentage of pathogens eradicated from the conjunctiva by day 6.Four patients still had infections by day 6, three with Streptococcus pneumoniae and one with Haemophilus influenzae, the researchers said.Mild adverse reactions included ocular burning (4.2%), itching (2.8%) and general discomfort (2.8%).
Posted by mehdi khanlari at 10:20 PM | Comments (0)
Corneal inlay may be useful for presbyopes,
OSN August 2006
Surgical techniques and advancing technology are helping intracorneal inlays gain acceptance as a treatment option for emmetropic presbyopes, said Richard L. Lindstrom, MD...could help the almost 44 million emmetropic presbyopes in the United States.Dr. Lindstrom presented early results on 57 eyes that had been implanted with the fenestrated Acufocus Intracorneal Inlay lens. Patients ranged in age from 45 to 60 years, and baseline mean uncorrected distance visual acuity was 20/20. Near vision at baseline was J9.At the 9-month follow-up, results showed distance vision remained 20/20, and near vision improved to J1....Earlier work with fenestration technology proved unsuccessful for other applications,...The Acufocus lens is an ultrathin device, about 10 µm in thickness. It is made of an opaque biocompatible polymer, Dr. Lindstrom said. It features 1.6 mm pinhole apertures “placed randomly in a way that the brain will ignore, thereby removing the risk of visual disturbance,” Dr. Lindstrom said.After administering topical anesthesia for 5 to 10 minutes, the lens is implanted into an IntraLase pocket, he said. To date, 75 lenses have been implanted in the United States, and Dr. Lindstrom said that worldwide clinical trials are ongoing.
Posted by mehdi khanlari at 10:15 PM | Comments (0)
Placido-based corneal topography outdated, limited in scope
OSN Breaking News
Current placido-based corneal topography systems assume all corneas conform to a known conic section, not allowing for a more true shape representation, according to a surgeon speaking here.
In a keynote presentation at the American Society of Cataract and Refractive Surgery Summer Refractive Congress, Michael W. Belin, MD, discussed issues surrounding corneal topography. He said topographic analyses based only on placido-derived anterior curvature are incomplete; they show the corneal apex, line of sight and VK axis as the same.
He noted that in a study involving Bausch & Lomb’s Orbscan, the device incorrectly read the corneal thickness of one patient as being 37 µm thinner. It also showed an incorrect ectasia.
It is like relying on an X-ray when a MRI is available,” Dr. Belin said.
In comparison, elevation data is independent of axis, orientation or positioning, according to Dr. Belin. He said all further maps of curvature can be derived from accurate elevation data.
Keratoconus screening requires the use of topography systems that measure elevation data as their elemental requirement,” he said
Posted by aman at 09:51 PM | Comments (0)
Surface Ablation for Keratoconus
CRS August 2006
To understand why surface ablation may have a lower risk of inducing ectasia compared with LASIK, and why it is perhaps a viable surgical option for keratoconic patients, we can turn to the research performed by Michael Smolek, PhD, of New Orleans. Dr. Smolek has shown that the collagen fibers in the anterior portion of the cornea have interlamellar bridging fibers that help maintain the structural strength of the cornea.1-3 These bridging fibers bifurcate at various depths in the anterior stroma. The bifurcation helps tie all of the anterior lamellar fibers together for structural support. However, in deeper parts of the cornea, there are fewer bridging fibers. Because the posterior lamellar fibers run parallel to each other and lack these bridging fibers, the posterior (or deeper) part of the cornea is less stable and more susceptible to sheering motions and distension.
With this background in mind, surgeons can understand that treatments to the superficial portion of the cornea will thin the cornea but still leave enough of the bridging fibers in place to maintain structural integrity. Conversely, deeper ablations that remove the anterior lamellae will leave just the posterior lamellae in place. Because the posterior lamellae do not have a significant degree of bridging fibers, the cornea is weakened and becomes more susceptible to distension or ectasia .
SUCCESSFUL RESULTS REPORTED WITH SURFACE ABLATION
To date, a number of surgeons have described good results with performing surface ablation for forme fruste keratoconus and frank keratoconus. In 2003, Sylvia Norton, MD, of Syracuse, New York, presented data on the treatment of keratoconus with PRK. In Dr. Norton's study,4 of the 24 patients who underwent PRK with mild-to-moderate keratoconus, 80% achieved 20/40 or better BCVA. Two patients with severe keratoconus did not achieve sufficient quality of vision following PRK and underwent corneal transplants.
In 2004, Percy Amoils, FRCS, of Johannesburg, South Africa, presented data on the safety and efficacy of surface ablation for patients with forme fruste keratoconus or frank keratoconus. Dr. Amoils' study5 evaluated 65 eyes with forme fruste keratoconus and 14 eyes with frank keratoconus that received PRK. At the 7-year follow-up mark, most of the study's patients achieved good UCVA and BCVA postoperatively. Although some patients in his study experienced regression, in general, the patients were extremely pleased with their results postoperatively.
Posted by aman at 09:44 PM | Comments (0)
Cataractous Changes due to Posterior Chamber Flattening with a Posterior Chamber Phakic Intraocular Lens Secondary to the Administration of Pilocarpine
Ophthalmology Volume 113, Issue 8 , August 2006, Pages 1283-1288
Both eyes underwent uneventful ICL implantation for the correction of a manifest spherical equivalent of +7 diopters (D) in the right eye and +7.1 D in the left eye. The left eye was followed for 2 years without developing complications. The right eye, however, showed on the first postoperative day a fleckenlike opacification on the anterior pole of the crystalline lens after instillation on the operative day of 2% pilocarpine in an attempt to accelerate recovery from unwanted pupil dilation causing patient complaints of glare disability after surgery. Optical coherence tomography demonstrated complete contact of the ICL with the natural lens 24 hours postoperatively. Serial IOP measurements were always within the normal limits. The instillation of 1% cyclopentolate resulted in an increase in the ICL vault that measured 132 μm 24 hours later. Three days after the completion of a 3-day course of topical 1% cyclopentolate, the opacification was less dense and demarcated, and a 124-μm vault was measured. Three months postoperatively, the cataract was associated with a 3-line loss of BCVA and considerable degradation of the contrast sensitivity, especially at higher spatial frequencies and with a glare source, and corneal endothelial cell changes were within normal limits. One year after ICL implantation, the right eye had to undergo phacoemulsification and IOL implantation, which were uneventful.
Conclusions
Posterior chamber flattening with resulting crystalline lens opacification can occur immediately after the instillation of pilocarpine in an eye with a hyperopic ICL. Therefore, caution should be taken with the administration of cholinergic agonists such as pilocarpine in patients with phakic IOLs, at least if they are hyperopic ICLs.
Posted by mmiraftab at 01:29 PM | Comments (0)
Comparison of Polypropylene and Silicone Ahmed Glaucoma Valves
Ophthalmology Volume 113, Issue 8 , August 2006, Pages 1320-1326
Average follow-up was 12.8 months (range, 6–30 months) for the silicone plate group and 14.5 months (range, 6–30 months) for the polypropylene plate group (P = 0.063). At the last follow-up examination, the mean IOP was 13.8±3.9 mmHg and 17.3±6.5 mmHg (P<0.0001) and the mean number of antiglaucoma medications was 1.9±1.3 and 2.1±1.4 (P = 0.48) in the silicone plate and polypropylene plate groups, respectively. The life-table success rates for the silicone plate and polypropylene plate groups were 94.2% and 83.2% at 12 months and 82.4% and 56.7% at 24 months by definition 1, respectively (P = 0.035). When an IOP reduction of at least 30% was used for success criterion (definition 2), probabilities of success were 89.5% and 71.7% at 12 months and 78.3% and 68.5% at 24 months in the silicone and the polypropylene plate groups, respectively (P = 0.012). Visual outcomes were comparable between the 2 groups. However, complications including Tenon’s cyst were observed more frequently in the polypropylene plate than in the silicone plate group (P<0.05).
Conclusions
The silicone Ahmed Glaucoma Valve (model FP7) showed improved IOP reduction compared with the polypropylene (model S2) implant. Differences observed in mean IOP, success rate, and complications suggest that plate material may influence clinical outcome.
Posted by mmiraftab at 01:27 PM | Comments (0)
Centrum Use and Progression of Age-Related Cataract in the Age-Related Eye Disease Study
Ophthalmology Volume 113, Issue 8 , August 2006, Pages 1264-1270
Observational data from the AREDS and other studies suggest that use of a multivitamin may delay the progression of lens opacities. A National Eye Institute–sponsored clinical trial scheduled for completion in 2007 will provide additional data on Centrum use and cataract development.
Posted by mmiraftab at 10:19 AM | Comments (0)
Margin of error up to 28% in determining IOL calculations
OSN SuperSite Breaking News 8/7/2006
GUADALAJARA, Mexico — Choosing the calculation formula and calculating IOL power carries approximately a 28% margin of error for determining correct lens power, according to one ophthalmologist speaking here Carlos Johnson Villalobos, MD, analyzed the difference between power calculations and the visual acuity in a total of 152 eyes, including 15 hyperopes, 92 emmetropes and 42 myopes. He presented results here at the Mexican Congress of Ophthalmology. “Errors of 0.1 mm in the metrics of the anterior chamber affect the postoperative refraction approximately 1 D in myopes, 1.5 D in emmetropes and 2.5 D in hyperopes,” ...According to the study, 76% of all patients had an “adequate” visual acuity of 20/20 or 20/15. In the myopic group, there was a difference of 1.4 D in 58% of patients; 71% of emmetropes had a difference of ± 1.8 D; and 53% of hyperopes had a difference of 0.4 D, he said.“There is a margin of error in IOL calculation of 20.39% to place an IOL of a different constant to the calculated constant, and an error of 7.89% from the selection of an inadequate formula,”
Posted by mehdi khanlari at 09:38 AM | Comments (0)
Avastin plus triamcinolone improves outcomes in combination surgery
OSN SuperSite Breaking News 8/9/2006
GUADALAJARA, Mexico — Combination phaco-vitrectomy surgery plus triamcinolone and bevacizumab significantly reduces macular thickness and improves visual acuity, according to a study presented here.Sergio Eustolio Hernández Da Mota, MD, and colleagues conducted a prospective, non-randomized pilot study evaluating the efficacy of using triamcinolone and Avastin (bevacizumab, Genentech) during combination cataract and vitrectomy surgery. The researchers included 13 patients aged 40 to 78 years who had subcapsular posterior cataract and clinically significant diffuse macular edema.....The researchers found the combination surgery produced a significant reduction in macular thickness, measured using optical coherence tomography. Mean visual acuities also improved from 20/400 preoperatively to 20/40 at 6 months follow-up
Posted by mehdi khanlari at 09:33 AM | Comments (0)
August 10, 2006
Patients should be monitored for IOP elevation beyond six months after IVTA injection
BJO, August 2006
A retrospective analysis of 536 patients (570 eyes) finds 50.6 percent experienced a rise of at least 30 percent. A baseline IOP greater than 16 mmHg was a risk factor for post-injection IOP elevation, and 65.1 percent who had a second injection experienced an increase of at least 30 percent from baseline.
Posted by kjalali at 05:44 AM | Comments (0)
Centrum use may delay progression of cataracts
Ophthalmology, August 2006
Data from the AREDS study finds a lower incidence of any type of lens opacity in participants taking this multivitamin/mineral supplement after a median follow-up of 6.3 years. Nuclear opacities were significantly less common in Centrum users. There was a similar, though insignificant, reduction in risk of cortical lens events.
Posted by kjalali at 05:39 AM | Comments (0)
August 08, 2006
Topical fluconazole effective against fungal keratitis
OSN Breaking News
Sergio Sonego-Krone, MD, and colleagues reviewed the results of 23 fungal keratitis patients treated at the Ophthalmology Department of the Hospital de Clínicas in Asunción, Paraguay. Twelve patients were treated with topical fluconazole 0.2%, and 11 patients received both topical fluconazole 0.2% and oral ketoconazole 200 mg twice daily.
The researchers found that fungal keratitis resolved in 16 patients, but the addition of ketoconazole did not improve outcomes. Keratitis resolved in nine patients treated only with fluconazole (75%) and in seven patients treated with fluconazole plus ketoconazole (64%), according to the study.
Patients with small, superficial ulcers appeared to benefit more and had a significantly better prognosis compared to patients with large and deep ulcers, the authors noted.
Overall, seven patients (30%) showed no response to treatment and required surgery, according to the study.
Posted by aman at 11:36 PM | Comments (0)
Retinal Nerve Fiber Layer Thickness in Amblyopic Eyes
American Journal of Ophthalmology August 2006, Page 247
To compare the peripapillary retinal nerve fiber layer (RNFL) thickness of sound and amblyopic eyes... Institutional. study population: Patients with unilateral strabismic, anisometropic, or combined amblyopia. observation: Fast RNFL analysis with ocular coherence tomography (OCT) of sound and amblyopic eyes. measure: Mean RNFL thickness.ConclusionsWe found a small, but not clinically significant, difference in nerve fiber layer (NFL) thickness between amblyopic and sound eyes. Reliability was excellent, with most eyes testing within 7% of the first test.
Posted by mehdi khanlari at 11:28 PM | Comments (0)
Monovision tested to delay juvenile myopia progression
Eyeworld August 2006
A study that used monovision spectacles with children may offer some insight into how to delay myopia progression. The study was published last year in the British Journal of Ophthalmology and was written by John R. Phillips, Ph.D., Department of Optometry and Vision Science, University of Auckland, New Zealand.The study had an additional surprising result. Although the dominant eye of the study participants was corrected for distance and the fellow eye was corrected as needed for near, all children accommodated to read with the distance-corrected eye.“They chose to have their focusing driven by the distance-corrected eye,” said Dr. Phillips. “So, the near-corrected eye was always experiencing myopic defocus.”
Posted by mehdi khanlari at 11:21 PM | Comments (0)
Use of Verisyse iris-supported phakic intraocular lens for myopia in keratoconic patients
Journal of Cataract & Refractive Surgery
We report 2 patients with stable keratoconus and high myopia who benefited from implantation of an iris-supported phakic intraocular lens (Verisyse, AMO) for correction of their refractive error. Both patients had a postoperative uncorrected visual acuity of 20/40. Endothelial cell density showed at most a 4% decrease, and no evidence of keratoconus progression was witnessed...
Posted by mehdi khanlari at 11:13 PM | Comments (0)
Successful Tear Lipid Layer Treatment for Refractory Dry Eye in Office Workers by Low-Dose Lipid Application on the Full-Length Eyelid Margin
American Journal of Ophthalmology August 2006, Page 264
To test tear lipid layer treatment by low-dose lipid application on the full-length eyelid margin for the treatment of office workers with dry eyes refractory to conventional treatments...Thirty eyes of 30 office workers with dry eyes with dark tear interference images, which did not respond to conventional treatments, were included. To supply lipid using a commercially available nonpreserved topical medication having both polar and nonpolar lipid base, ofloxacin eye ointment (Santen Pharmaceutical, Osaka, Japan) was selected. Low-dose ofloxacin ointment application on the full-length eyelid margin was carried out three times a day for two weeks. The symptom of ocular dryness using a visual analog scale, tear interferometry to assess lipid layer thickness (LLT), corneal fluorescein staining, tear-film breakup time (BUT), and meibum expressibility gradings were compared....Conclusion For office workers with refractory dry eyes, tear lipid layer treatment by low-dose ointment applied on the full-length eyelid margin was shown to be an effective approach. The applied lipid formed a uniform lipid layer, which contributed to tear stability, leading to the improvement of the symptom.
Posted by mehdi khanlari at 11:07 PM | Comments (0)
Influence of severity of nuclear cataract on optical biometry
Journal of Cataract & Refractive Surgery July 2006, Pages 1161-1165
To compare preoperative and postoperative measurements of the axial length (AL) performed with the IOLMaster (Carl Zeiss Meditec) to evaluate the effect of nuclear cataract on the optical biometry.In 245 consecutive eyes of 162 patients scheduled for cataract surgery, type and severity of cataract was evaluated using the Lens Opacities Classification System III. Preoperative and postoperative axial length measurements were performed with the IOLMaster. The postoperative readings of AL were corrected for the IOL optic material implanted....The preoperative AL measurements were 0.07 mm ± 0.05 (SD) (range −0.18 to 0.11 mm) longer than the postoperative measurements (P<.001). These differences in AL were only weakly correlated (r = −0.28, P = .01) with the nuclear cataract grade, mean 3.5 ± 0.9.ConclusionIn this study, AL measurements with optical biometry using the IOLMaster were not influenced by the severity of nuclear cataract to a clinically relevant degree. Furthermore, it was found that AL in the phakic eye was overestimated by about 0.07 mm because of a slightly too low value of the group refractive index used for the crystalline lens.
Posted by mehdi khanlari at 10:58 PM | Comments (0)
Health Literacy and Adherence to Glaucoma Therapy
American Journal of Ophthalmology August 2006
Conclusions: Many patients with open angle glaucoma may have poor health literacy. The subjects in our study with low literacy were less adherent with their glaucoma medications than those with a higher level of literacy. Interventions specifically targeting patients with low literacy may improve medication adherence...
Posted by mehdi khanlari at 04:34 PM | Comments (0)
Autologous Serum for the Treatment of Corneal Epithelial Abrasions in Diabetic Patients Undergoing Vitrectomy
American Journal of Ophthalmology August 2006, Pages 207-211
To compare the effect of autologous serum versus hyaluronic acid for the treatment of epithelial corneal lesions in patients such as diabetics with reduced wound healing....Diabetic patients undergoing pars plana vitrectomy mostly combined with cataract extraction and intraocular lens (IOL) implantation who received corneal abrasion for better intraoperative visualization were included in this study. A standardized 8-mm diameter corneal abrasion was performed. Patients were randomized into one group treated with hourly application of autologous serum and another treated with hyaluronic acid drops (Vislube). Besides the time necessary for closure of the corneal epithelium other parameters such as patients’ age, gender, duration of surgery, history of diabetes, and current HbA1C were evaluated..... Mean epithelialization time was 7.1 days in the hyaluronic acid group. In the autologous serum group, epithelium healed after a mean of 4.3 days....Conclusions
It appears that autologous serum leads to a much faster closure of corneal epithelial wounds after abrasion compared with artificial tears.
Posted by mehdi khanlari at 04:21 PM | Comments (0)
BURNSTINE LACRIMAL CANNULA
Ophthalmology Management August 2006
The Burnstine Lacrimal Cannula was developed by Michael Burnstine, M.D., for use in lacrimal irrigationThe Burnstine Lacrimal Cannula is a 23-gauge cannula featuring an end-opening port for direct irrigation and a tapered tip for ease of entry into an undilated punctum. The 13-mm length makes it ideal to probe as well as irrigate the proximal lacrimal system, eliminating the need for placement of Bowman probes to measure canalicular obstruction, says Katena.
Katena Products, Inc.
Posted by mehdi khanlari at 04:19 PM | Comments (0)
GEGGEL CORNEAL CHILLER
Ophthalmology Management august 2006
The Chiller rests on the cornea using gravity to secure a water-tight seal.The Geggel Chiller, developed in coordination with Harry S. Geggel, M.D., is designed to thoroughly chill the entire cornea before or after PRK, LASIK and LASEK surgery.The instrument helps minimize corneal scarring, diminish postoperative haze, reduce pain to the patient and stabilize refractive results
Posted by mehdi khanlari at 04:07 PM | Comments (0)
GEGGEL CORNEAL CHILLER
Ophthalmology Management august 2006
The Chiller rests on the cornea using gravity to secure a water-tight seal.The Geggel Chiller, developed in coordination with Harry S. Geggel, M.D., is designed to thoroughly chill the entire cornea before or after PRK, LASIK and LASEK surgery.The instrument helps minimize corneal scarring, diminish postoperative haze, reduce pain to the patient and stabilize refractive results
Posted by mehdi khanlari at 04:07 PM | Comments (0)
August 06, 2006
Femtosecond laser in situ keratomileusis after radial keratotomy
JCRS Pages 1270-1275 (August 2006)
patients with residual low myopia after previous RK who had surgery with the IntraLase femtosecond laser (IntraLase Corp.) and the Star 2 excimer laser (Visx, Inc.). UCVA, BSCVA, defocus equivalent, refraction, flap thickness, flap diameter, and intraoperative complications were evaluated over a minimum 6-month follow-up.
Results
Although the RK incisions opened in all eyes when the flap was lifted, LASIK was successfully completed in all cases. Mean flap thickness was 119 μm . There were no cases of slipped flaps, microstriae, or epithelial ingrowth. Defocus equivalent was reduced from a mean of 2.51 D to 0.52 D;
Conclusions
The femtosecond laser was safely used to create thin LASIK flaps in eyes with previous RK. An increased postoperative inflammatory response may explain the loss of BSCVA in some cases. Efficacy and predictability of the procedure were comparable to those of LASIK after RK with mechanical microkeratomes.
Posted by alireza habibollahi at 02:38 PM | Comments (0)
Excimer laser-assisted anterior lamellar keratoplasty for keratoconus, corneal problems after laser in situ keratomileusis, and corneal stromal opacities
JCRS Pages 1264-1269 (August 2006)
To evaluate excimer laser-assisted anterior lamellar keratoplasty to augment thin corneas as in keratoconus (<350 μm) and corneal ectasia after laser in situ keratomileusis (LASIK) and to treat anterior stromal opacities.
Methods
Thirteen eyes (5 keratoconus, 3 macular dystrophies, 1 post-LASIK ectasia, 1 post-LASIK interstitial keratitis, 3 post-herpetic keratitis sequelae) of 13 patients were included in this prospective study. The treatment group was divided into corneal ectasia and stromal opacity groups. A donor stromal button approximately 350 μm thick received a 100 μm excimer laser ablation on the endothelium. The remaining cornea (epithelium, Bowman's membrane, and stroma) was punched with a 7.5 or 7.7 mm trephine. After transepithelial ablation of the host cornea to 200 μm thickness, the corneal button was sutured with interrupted 10-0 monofilament nylon. Sutures were removed between 3 months and 6 months postoperatively. Preoperative and postoperative simulated keratometric cylinders and corneal thickness values were compared using the Wilcoxon signed rank test. The postoperative spherical equivalent refraction and best spectacle-corrected visual acuity (BSCVA) between the groups were compared using the Mann-Whitney U test.
Results
The mean follow-up was 27.6 months ± 8.3 (SD). All patients gained 2 lines or more of BSCVA, and no patient lost a line. The mean corneal thickness was 381.2 ± 88.2 μm preoperatively, which significantly increased to 534.9 ± 96.6 μm postoperatively (P<.05). The mean preoperative simulated keratometric cylinder was 7.44 ± 7.18 diopters (D); postoperatively, it decreased to 2.61 ± 1.73 D (P<.05). There was no significant difference in postoperative spherical equivalent refraction or BSCVA between the groups (P>.05).
Conclusions
This technique presents a different modality for the treatment of keratoconus, post-LASIK corneal problems, and other corneal stromal opacities with anterior lamellar keratoplasty. Additional studies with more patients and longer follow-up will help determine the role of this technique as a substitute for penetrating keratoplasty in these patients.
Posted by alireza habibollahi at 02:29 PM | Comments (0)
Scleral fixation using suture retrieval through a scleral tunnel
Posted by alireza habibollahi at 02:24 PM | Comments (0)
Use of the Unfolder Silver/Sapphire system to inject capsular tension ring during phacoemulsification in cases with subluxated cataract
JCRS Pages 1256-1258 (August 2006)
Capsular tension rings (CTRs) have proved to be useful devices in cataract surgery in cases of zonular weakness and dialysis. They can be inserted with the help of forceps or commercially available injection systems. We describe use of the Unfolder Silver/Sapphire Series implantation system (Advanced Medical Optics, Inc.) to inject a CTR into the capsular bag during phacoemulsification in cases with subluxated cataract. The implantation system used for CTR insertion can subsequently be used for implantation of a foldable intraocular lens
Posted by alireza habibollahi at 02:19 PM | Comments (0)
Use of the Unfolder Silver/Sapphire system to inject capsular tension ring during phacoemulsification in cases with subluxated cataract
JCRS Pages 1256-1258 (August 2006)
Capsular tension rings (CTRs) have proved to be useful devices in cataract surgery in cases of zonular weakness and dialysis. They can be inserted with the help of forceps or commercially available injection systems. We describe use of the Unfolder Silver/Sapphire Series implantation system (Advanced Medical Optics, Inc.) to inject a CTR into the capsular bag during phacoemulsification in cases with subluxated cataract. The implantation system used for CTR insertion can subsequently be used for implantation of a foldable intraocular lens
Posted by alireza habibollahi at 02:19 PM | Comments (0)
Ring-shaped caliper for better anterior capsulorhexis sizing and centration
JCRS 1253-1255 (August 2006)
Accepted 17 February 2006
We describe a new type of caliper to optimize the size, shape, and centration of the capsulorhexis during intraocular lens (IOL) surgery. This flexible, ring-shaped tool is positioned on the anterior capsule surface, where it is kept in place by an ophthalmic viscosurgical device. When in place, the caliper provides an ideal guide for the surgeon to follow and facilitates optimal capsulorhexis shape and centration.
Posted by alireza habibollahi at 02:17 PM | Comments (0)
Toxic anterior segment syndrome after Verisyse iris-supported phakic intraocular lens implantation
Journal of Cataract & Refractive Surgery July 2006,
Majid Moshirfar MD, a, , George Whiteheada, Barry C. Beutlera and Nick Mamalis MDa
We report a case of toxic anterior segment syndrome (TASS) after implantation of a Verisyse (AMO) iris-supported phakic intraocular lens (IOL). The patient presented the day after surgery with significant decreased visual acuity and severe, persistent, limbus-to-limbus corneal edema. After treatment with topical steroids, oral steroids, nonsteroidal antiinflammatory agents, and hypertonic solution, the edema resolved over the course of 2 months and best corrected visual acuity improved to 20/20. Toxic anterior segment syndrome has been reported after implantation of IOLs previously, but this new case of TASS should alert surgeons to the possibility of the syndrome after phakic IOL placement.
Posted by mehdi khanlari at 07:57 AM | Comments (0)
August 05, 2006
Pigment Release and Secondary Glaucoma After Implantation of Single-piece Acrylic Intraocular Lenses in the Ciliary Sulcus
AJO AUGUST 2006
HAIOL was implanted in the ciliary sulcus of 20 eyes that developed posterior capsule rupture during phacoemulsification
Results
Postoperative best-corrected visual acuity was 20/40 or better in all eyes. The mean postoperative sphere was −0.5 ± 0.7 diopters (range +1.25 to −2.00); the mean postoperative cylinder was −1.2 ± 0.8 diopters (range 0 to −2.50). None of the HAIOLs was decentered or dislocated, and none required repositioning. Seven eyes (35%) developed pigment release; three eyes (15%) developed secondary glaucoma.
Conclusions
Implantation of single-piece HAIOLs in the ciliary sulcus is associated with pigment release and secondary glaucoma. Alternative methods of aphakic correction should be considered
Posted by aman at 10:52 PM | Comments (0)
Comparison of Deep Lamellar Keratoplasty and Penetrating Keratoplasty for Lattice and Macular Corneal Dystrophies
AJO August 2006
We reviewed the clinical records of 84 eyes with LCD or MCD who had DLKP (41 eyes) or PKP (43 eyes). Primary pathology consisted of 60 eyes with LCD and 24 eyes with MCD. DLKP was performed by either removing stromal tissue gradually, or by viscodissection of Descemet’s membrane. Graft clarity, best-corrected visual acuity (BCVA), endothelial density, and complications were compared between DLKP and PKP, as well as between LCD and MCD.
Results
All 84 eyes showed a postoperative improvement in visual acuity. The median final BCVA was not significantly different between PKP and DLKP groups. Endothelial cell loss rates were similar for DLKP and PKP. While the MCD-DLKP group showed progressive decrease in endothelial density, this was not observed in the LCD-DLKP group after surgery. In the DLKP group, most of the complications occurred intraoperatively or in the early phase, whereas late phase complications such as endothelial rejection and secondary glaucoma were the main complications in the PKP group.
Conclusions
PKP is no longer an automatic choice for the surgical treatment for LCD and MCD; DLKP seems to be a safe alternative. While DLKP is a favorable method for LCD, MCD may not be a good candidate, as it might show progressive decrease in the corneal endothelium postoperatively.
Posted by aman at 10:47 PM | Comments (0)
Stereopsis in Refractive Surgery
AJO August 2006
Eighty-three patients were studied; 55 had sequential bilateral and 28 had unilateral treatment. Mean age was 32 years. Stereopsis was measured using a multitarget red-green anaglyph stereo vision test. Only patients with fine preoperative stereopsis were included in the study. Repeat measurements were taken one week laser-assisted in situ keratomileusis (LASIK) or three weeks laser epithelial keratomileusis (LASEK) after treatment of one eye in all patients. Further measurements were taken at six and 12 weeks in unilaterally treated patients and after treatment of the fellow eye in bilaterally treated patients.
Results
A total of 38.6% of patients retained fine stereopsis (28 to 41 seconds of arc) over a range of anisometropia from 0.625 to 4.375. Moderate stereopsis (66 to 526 seconds of arc) was recorded 28.9% in the presence of 1.375 to 5.525 diopters of anisometropia. Poor/absent stereopsis (≤2000 seconds of arc) was found in 32.5% in the presence of 2.1 to 8.0 diopters of anisometropia. A strong correlation was found between stereopsis and anisometropia, but interpatient variability was found. Uncorrected visual acuity (UCVA) in the untreated eye of ≥20/200 was associated with retention of fine stereopsis. Unilaterally treated patients showed improvement in stereopsis at six weeks after surgery. Sequential bilateral treatment had no deleterious effect on stereopsis.
Posted by aman at 10:35 PM | Comments (0)
August 04, 2006
Custom-contoured ablation pattern method for the treatment of decentered laser ablations
J Cataract Refract Surg. 2004 Aug;30(8):1675-84
PURPOSE: To evaluate the custom-contoured ablation pattern (C-CAP) method as a tool for providing customized laser ablations for decentered ablations based on corneal topography data. SETTING: Department of Ophthalmology, Stanford University, Stanford, California, USA. METHODS: In a prospective noncomparative interventional case series, 8 eyes from 7 post-laser in situ keratomileusis (LASIK) patients and 1 post-photorefractive keratectomy (PRK) patient with symptomatic laser decentration were treated with the C-CAP method. The Zeiss Humphrey topography system was used to identify and analyze decentered ablations. The computer software allowed the surgeon to preoperatively model the effect of various ablation schemes on the preoperative topography until a scheme that alleviated the decentration was identified. The planned ablation parameters, which included size, depth, and location of the ablation, were programmed into the Visx S4 excimer laser before treatment. RESULTS: The mean follow-up after C-CAP ablation was 4.2 months (range 1.8 to 6.3 months). At the last postoperative examination, no eye lost a line of best spectacle-corrected visual acuity (BSCVA). The uncorrected visual acuity (UCVA) improved by 3 lines in 1 eye (12.5%), by 2 lines in 1 eye (12.5%), and by 1 line in 3 eyes (37.5%); it remained unchanged in 2 eyes (25.0%) and decreased by 1 line in 1 eye (12.5%). The BSCVA improved by 3 lines in 1 eye (12.5%), by 2 lines in 2 eyes (25.0%), and by 1 line in 3 eyes (37.5%); it remained unchanged in 2 eyes (25.0%). In all eyes, including those without improvement in UCVA or BSCVA, a significant improvement in centration and subjective complaints was achieved. The pre-C-CAP and post-C-CAP root-mean-square (RMS) wavefront data were available in 5 of 8 eyes. The total and higher-order RMS aberrations decreased by 41.7% (P =.0027) and 45.5% (P =.039), respectively, after C-CAP treatment. CONCLUSIONS: Early U.S. results show the topography-driven C-CAP method is an effective tool to address untreatable postsurgical decentration. This method is presented as a technique to enhance the overall quality of vision, reduce patient-perceived visual aberrations, regularize the corneal surface, and maximize BSCVA.
Posted by mmiraftab at 07:42 PM | Comments (0)
STANDARD VERSUS CUSTOMIZED ABLATION
To determine whether improved outcomes with customized ablations are primarily related to wavefront-guided treatments, the Star S4 laser system should be examined and a comparison of its standard and customized ablations performed. For standard ablations, the Star S4 uses a broad-beam laser, performs a prophylactic central-island treatment, and has a maximum optical zone size of 6.5mm. With a case of pure astigmatism (eg, plano = -2.00D x 90), the short meridian is only 5mm. However, with a customized ablation, the system uses variable-spot scanning, with which there is a change in shot-pattern delivery. Consequently, no prophylactic-island treatment is required, the optical zones are enlarged, and wavefront-guided ablations have been added. The Star S4 produces superior results with wavefront-guided treatments compared with standard ablations. In the majority of primary surgeries that have a low incidence of preoperative higher-order aberrations, I believe these improved outcomes are related not to wavefront technology, but to other changes made to the laser program. These aforesaid changes are included in the Allegretto Wave’s standard treatment. Noteably, engineers who added wavefront technology their own laser systems without making other changes to the platforms did not find any difference in surgical outcomes by adding wavefront alone.
Posted by mmiraftab at 07:40 PM | Comments (0)
A comparison of induced astigmatism in conventional and wavefront-guided myopic LASIK using LADARVision4000 and VISX S4 platforms
J Refract Surg. 2005 Nov-Dec;21(6):S792-8
PURPOSE: To evaluate and compare the surgically induced astigmatism in myopic eyes undergoing conventional and wavefront-guided LASIK. METHODS: A retrospective review was performed of the charts of 200 myopic eyes of 121 patients who underwent either custom or conventional treatments via the VISX S4 or LADARVision4000 platforms (50 consecutive eyes in each of the four groups). The primary outcome measure was manifest refraction, which was evaluated preoperatively and at 3 months postoperatively. The magnitude and axis of the unintended surgically induced astigmatism were calculated using vector analysis. The Student t test was used to compare the magnitudes of the surgically induced astigmatism and the absolute angle of error. RESULTS: The mean preoperative manifest cylinder was 0.66 +/- 0.38 diopters (D) for conventional VISX S4 and 0.68 +/- 0.39 D for VISX CustomVue (P = .795), and 0.76 +/- 0.56 D for LADARVision and 0.61 +/- 0.36 D for LADAR CustomCornea (P = .114). The success index was 0.19 +/- 0.41 for VISX S4 and 0.49 +/- 0.49 for VISX CustomVue (P = .0013), and 0.25 +/- 0.47 for LADARVision and 0.20 +/- 0.39 for LADAR CustomCornea (P = .5721). The absolute mean angle of error was 4.4 +/- 13.9 degrees for VISX S4 versus 14.9 +/- 23.9 degrees for VISX CustomVue (P = .0085), and 6.1 +/- 12.30 for LADARVision versus 3.9 +/- 11.1 degrees for LADAR CustomCornea (P = .3501). Of the VISX CustomVue eyes, 32% had an absolute angle of error > 10 degrees, as compared to 10% for both the VISX S4 and LADAR CustomCornea eyes (P = .013), and 16% for the LADARVision group (P = .056). CONCLUSIONS: Wavefront-guided ablation is associated with higher surgically induced astigmatism and larger astigmatic axis shift on the VISX platform as compared to the LADAR CustomCornea and the LADAR and VISX conventional platforms. Care should be emphasized mainly during registration/alignment to minimize surgically induced astigmatism in wavefront-guided LASIK.<