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March 29, 2005
More genetic studies shed light on AMD
OSN 2005
Three studies conducted independently of one another have linked a single gene variation to an increased risk for development of age-related macular degeneration. A separate study in twins has also shown the influence of genetics on the disease. The three studies, found that a single nucleotide polymorphism of the complement factor H gene increases the risk of development of AMD by at least threefold. This single genetic variation may be responsible for up to 50% of all AMD cases.
Posted by kjalali at 08:00 AM | Comments (0)
Cancer drug shows promise as systemic AMD treatment
OSN 2005
Drug used for treating colorectal cancer has shown promising early results as a systemic treatment for choroidal neovascularization in age-related macular degeneration. Genentech’s Avastin (bevacizumab) was shown to “substantially reduce the leakage from abnormal blood vessels in eyes of patients with neovascular (wet) age-related macular degeneration. Avastin was approved by the Food and Drug Administration in February 2004 for treatment of colorectal cancer. The drug is designed to inhibit angiogenesis by blocking vascular endothelial growth factor.
Posted by kjalali at 07:55 AM | Comments (0)
Macular translocation shows promise in patients with CNV
OSN 2005
Macular translocation with 360º retinotomy can stabilize and in some cases improve visual acuity in patients with subfoveal choroidal neovascularization caused by age-related macular degeneration. At 6 months postoperatively, three of the seven patients demonstrated improved near visual acuity, with near VA of 20/200 or better, and two patients demonstrated stabilized near VA. Two patients lost three or more lines of Snellen acuity, so patients who start out with good vision should be handled with extreme care.
Posted by kjalali at 07:50 AM | Comments (0)
March 27, 2005
A Systematic Review of the Applicability and Efficacy of Eye Exercises
Journal of Pediatric Ophthalmology and Strabismus, March/April, 2005
Eye exercises have been purported to improve a wide range of conditions including vergence problems, ocular motility disorders, accommodative dysfunction, amblyopia, learning disabilities, dyslexia, asthenopia, myopia, motion sickness, sports performance, stereopsis, visual field defects, visual acuity, and general well-being. Small controlled trials and a large number of cases support the treatment of convergence insufficiency. Less robust, but believable, evidence indicates visual training may be useful in developing fine stereoscopic skills and improving visual field remnants after brain damage. As yet there is no clear scientific evidence published in the mainstream literature supporting the use of eye exercises in the remainder of the areas reviewed, and their use therefore remains controversial.
Posted by afarahi at 06:17 AM | Comments (0)
Minimal daily patching improves intermittent exotropia
OSN,March,2005
“Part-time patching increases accommodative fusional convergence and reduces the angle of intermittent exotropia,” reported Yoonae A. Cho, MD, PhD, and colleagues from South Korea in a poster at the American Association for Pediatric Ophthalmology and Strabismus meeting. Their study found that 3 hours of patching per day was effective in reducing exo-angle, at near, after 3 months of therapy.
Posted by afarahi at 06:10 AM | Comments (0)
Intracameral air viable alternative for hydrops
OSN,March,2005
Injecting intracameral air as a treatment for hydrops secondary to keratoconus is a safe and economical alternative to conventional treatments, according to a speaker here at the Pan-American Congress of Ophthalmology.
Dr. Hernández and colleagues studied 84 patients with keratoconus to see who would develop hydrops. A total of 11 eyes of 10 patients presented with corneal hydrops secondary to keratoconus. These were divided into two groups; Group A received an injection of intracameral air (roughly 0.2 mL of air), and Group B was treated conventionally with hyperosmotics, beta-blockers and fluoromethalone.
In Group A, pain, tears and other symptoms nearly vanished, visual recuperation was improved, and recuperation time was reduced by nearly two-thirds.
“The rapid resolution of hydrops helps us to conduct transplants within a shorter time period. It helps us to perhaps think about other types of surgery, such as deep lamellar keratoplasty, which cannot be done when there is hydrops. Obviously, this could also help to reduce the percentage of (corneal) grafts that are rejected,” he said.
Posted by afarahi at 05:28 AM | Comments (0)
Meningococcal septicemia presenting as bilateral endophthalmitis
JCRS FEB 2005
We present a patient with bilateral endophthalmitis as the presenting sign of meningococcal septicemia. Systematic examination and vitreous tap conclusively identified the microbe, and appropriate treatment was administered, with good recovery of vision.
Posted by alireza habibollahi at 02:37 AM | Comments (0)
Clinical results of ZSAL-4 angle-supported phakic intraocular lenses in 190 myopic eyes
JCRS FEB 2005
Italy,To evaluate the efficacy and safety of angle-supported phakic intraocular lenses (IOLs) in myopia.
Methods
This prospective noncomparative single-surgeon interventional case series comprised 190 consecutive myopic eyes of 115 patients having implantation of a ZSAL-4 IOL (Morcher GmbH) through a 5.5 mm × 3.0 mm sclerocorneal tunnel along the steepest meridian with a surgical iridectomy. Preoperatively, the mean spherical equivalent was −14.37 diopters (D) ± 4.40 (SD) and the mean astigmatism, 1.66 ± 1.36 D.
Conclusions
Angle-supported IOLs can effectively correct high myopia, although residual refractive errors may require secondary procedures. The main intraoperative and postoperative complications were halos, steroid response, and incorrect IOL sizing. The role of surgery in inducing macular hemorrhages should be assessed further.
Posted by alireza habibollahi at 02:31 AM | Comments (0)
Simultaneous surgeon and side-view video analysis comparing in situ fracture and stop-and-chop phacoemulsification
JCRS FEB 2005
A simultaneous surgeon and side-view camera video analysis demonstrated that in situ fracture requires more ultrasonic power behind the iris than the stop-and-chop technique, which requires a longer period of manipulation of larger fragments in the anterior chamber.
Posted by alireza habibollahi at 02:27 AM | Comments (0)
Visual prognosis of amblyopia associated with myelinated retinal nerve fibers
AJO,Feb,2005
Twelve children with amblyopia associated with anisomyopia and myelinated nerve fibers were treated with spectacle correction after cycloplegic refraction and occlusion therapy for amblyopia.The mean refractive error of the 12 children in spherical equivalents was −8.16 diopters (range −1.50 to approximately −13.00 diopters). The mean age at the initiation of therapy was 4.2 years (range 2.1 to 8.6) and the mean follow-up period was 2.6 years (range 0.5 to 5.1). After the occlusion treatment, visual acuity improved to 20/30 in four patients, and to 20/60 in one patient. In the remaining six patients, visual acuity remained at 20/200 or worse. The amount of anisometropia and the area of myelination were significantly different between the group with a final visual acuity of 20/40 or better and the group with a final visual acuity of worse than 20/200.
Conclusion:The visual acuity of about one third of the amblyopes with myelinated nerve fibers improved to 20/30. The prognostic factors for the visual improvement were the amount of anisometropia and the area of myelination.
Posted by afarahi at 12:29 AM | Comments (0)
March 23, 2005
Labeling system will use exact refraction values on IOL package
OSN March 2005
A labeling system that displays exact refraction values on IOL packages, rather than 0.5D step values, has been developed in Germany to attempt to enhance the postoperative refractive outcome of cataract surgery. Manufacturers are now in a phase of quality development in which subtle factors such as IOL power labeling are being scrutinized The German ophthalmic company Technomed has begun using the exact labeling on its EasyCare 600 IOL and is offering ophthalmologists the option to order whatever lens power they need through a special mailing service.The new labels will include both the common 0.5D step labeling and new exact refraction values that specify the power of the lens down to 0.01 D, according to the company. This will minimize the postop refractive error associated with mismatched lens power, according to Technomed officials.Problems with ISO standards
With standard package labeling, surgeons assumed that the power of the IOL in the package was within ±0.25 D of the labeled dioptric power, Dr. Neuhann said, when in fact the manufacturing tolerances set out by ISO are much broader. This often led to error in the final surgical outcome, he said.In traditional labeling, the tolerance permitted by ISO is ±0.3 D for IOLs with powers from 0 D to 15 D; ±0.4 D for powers greater than 15 D up to 25 D; ±0.5 D for powers greater than 25 D up to 30 D; and ±1 D for powers greater than 30 D, according to information provided by Technomed The company provided an example of the difference in the possible range of error. With traditional labeling, to achieve a required refraction of 21.31 D for emmetropia, an ophthalmologist would select a lens labeled 21.5 D. But within the ISO tolerances the actual power of such a lens might be 21.9 D, resulting in a refractive mismatch of 0.59 D.
Posted by mehdi khanlari at 07:53 PM | Comments (0)
March 22, 2005
Trial tests microplasmin for easier vitrectomies
Ophthalmology TimesMar 1, 2005
Dublin, Ireland—An Irish biotechnology company is hoping recombinant microplasmin will simplify vitrectomy in patients with vitreoretinal disorders.ThromboGenics Ltd. is enrolling up to 50 patients at three centers in The Nether- lands and Germany for a phase II trial using plasmin for induction of a posterior vitreous detachment (PVD),ThromboGenics and NuVue have a formal licensing agreement for plasmin-based compounds used to treat eye diseases.The trial, which treated the first patient in December, is designed to help investigators determine the dose selection for future clinical trials. ThromboGenics hopes to submit an investigational new drug application to the FDA in 2005.The company believes a drug given prior to vitrectomy could lead to more rapid surgery, in an office setting, with fewer complications. It previously has worked on biotherapeutics for the prevention and treatment of heart attack, stroke, peripheral artery disease, and cancer
Posted by mehdi khanlari at 12:47 PM | Comments (0)
Maximizing impact of informed consent
The way in which informed consent is broached can have a significant impact on what the patient ultimately takes away from the meeting.To increase the impact of informed consent, Dr. Hutnik recommended making sure that it’s surgery specific.“Whether it’s eye surgery and specifically cataract surgery versus a vitrectomy, versus knee surgery, it should be specifically spelled out and not only can you say that you did it, you have to prove that you spelled it out,” Dr. Hutnik said.“So, I think what physicians can do is to have a triplicate copy — one that goes to the patient, one that goes to the physician, and one that goes to the hospital,” she said.The document should be signed by the patient, which suggests that at the very least they have seen the informed consent. “One cannot imply that there was a very healthy verbal discussion between the patient and the physician,” Dr. Hutnik said. “It’s on the onus of the physician to prove that they did this, and having a written document, that is surgery specific and is signed by the patient is probably the best you can do.”
Posted by mehdi khanlari at 12:24 PM | Comments (0)
Early squalamine results positive
Eyeworld March 2005
Preliminary results of a multicenter open-label U.S. Phase II clinical trial of squalamine (Genaera Corp., Plymouth Meeting, Pa.), a treatment for choroidal neovascularization associated with age-related macular degeneration (AMD), were positive, according to the manufacturer.The preliminary results from six patients treated with 40 mg of squalamine, each of whom suffered from wet AMD in both eyes, demonstrated all eyes had preserved or improved vision at week three (after two doses), week five (end of therapy) and two months after initiation of therapy. The greatest degree of improvement at two months was a gain relative to baseline of 28 letters (5.6 lines), while the greatest degree of loss was 11 letters on the ETDRS chart. All patients received four weekly doses of squalamine, a systemically delivered anti-angiogenic drug, with no further maintenance therapy.No patients withdrew from therapy, and no drug-related serious adverse events have yet occurred in the trial, according to the manufacturer.
Posted by mehdi khanlari at 10:29 AM | Comments (0)
Pearls for phaco chop presented
Eyeworld March 2005
Phaco chop offers several advantages including decreased phaco power and time, decreased stress on the zonules, supracapsular emulsification, and the ability to keep the phaco tip central, Dr. Braga-Mele offered the following pearls to those interested in learning the chop:
Start with chop;
hydrodelineate;
create epinucleus shell;
keep phaco tip deep and proximal;
keep chopper tip deep;
use capsular dye; and
select cases with small, firm endonucleus.
When chopping, use a 30-degree bevel phaco needle and begin with the bevel down, said Dr. Braga-Mele. Retract the silicone sleeve, exposing more of the metal needle. That maximizes deeper purchase and is not a factor with MICS.Before surgeons impale, they should place the chop instrument in front and to the side of the needle.Then, chop in half by bringing the chopper to the left and slightly down when moving the phaco needle to the right and up slightly.Propagate the cleavage plane laterally and through the posterior plate. Until you see red, don’t chop, said Dr. Braga-Mele. When chopping, rotate the nucleus and repeat. Then, turn the bevel sideways to achieve better purchase. Hyperpulse and microbursts increase followability of segments.It’s important for surgeons to remember the size of the pie segments vary according to nucleus density
Posted by mehdi khanlari at 09:10 AM | Comments (0)
AquaLase praised for safety
Eyeworld March 2005
Liquification cataract removal (AquaLase, Alcon, Fort Worth, Texas) requires surgeons to rethink technology, anatomy, and technique to best use the equipment, said Robert P. Lehmann, M.D., Baylor College of Medicine, Houston.In a four-year experience initially with Legacy (Alcon, Fort Worth, Texas) fluidics and subsequently with the Infiniti Vision System (Alcon) in more than 1,100 cases (on approximately one-third of cataract and all refractive lens case patients), Dr. Lehmann found the technology requires less movement of the tip and occlusion was only possible in position two.
Therefore, surgeon understanding and recognition of nuclear anatomy is more important than ever.Dr. Lehmann said his clinical experiences show the method has the following advantages: “Smaller” rhexis is easily maintained; capsules are cleaner with less cortical clean up; very clear corneas are produced (in the bag energy); pc friendlier than ultrasound needle; and it is a “kinder, gentler procedure and learning curve.”
Posted by mehdi khanlari at 09:06 AM | Comments (0)
March 20, 2005
Trabeculectomy With Internal Tube Shunt: A Novel Glaucoma Surgery
Journal of Glaucoma. 14(2):91-97, April 2005.
To describe a pilot study that evaluates the efficacy and mechanism of action of a new glaucoma operation, trabeculectomy with internal tube shuntMethods: Twenty-three patients underwent the new operation in one eye for open angle glaucoma. Under a scleral flap, a deep sclerectomy was performed, resulting in an intrascleral lake. Laterally, on both sides, a small silicone tube was placed between the intrascleral lake and the suprachoroidal space. A trabeculectomy stoma and a peripheral iridectomy permitted easy access of aqueous to the tube. Postoperative and preoperative results were analyzed and also compared with results of 45 eyes that underwent a conventional trabeculectomy.After a mean follow-up time of 324 days, the mean postoperative IOP was 13.8 mm Hg compared with a preoperative value of 25.4 mm Hg. The mean number of postoperative medications was only 1.1 compared with a preoperative value of 3.0. No significant change in outflow facility was seen. The bleb size was very small. In comparison, in conventional trabeculectomy eyes, the outflow facility and bleb size were significantly larger.Conclusion: Trabeculectomy with internal tube shunt is very effective in lowering IOP. It is postulated to work, to a large extent, by allowing access of the aqueous humor to the suprachoroidal space where the protein colloid osmotic pressure of uveal blood causes its absorption. This new procedure offers many advantages over other filter procedures and tube shunts.
Posted by mehdi khanlari at 11:28 AM | Comments (0)
Glare disability and spherical aberration with five foldable intraocular lenses
Acta Ophthalmologica Scandinavica March 2005
To compare differences in subjective glare and spherical aberration between five foldable intraocular lenses (IOLs) made of different materials and to different designs...Conclusions: New generation IOLs such as the Pharmacia Z9000, AMO AR40e and AcrySof� SA30AL have a lower incidence of glare and spherical aberrations; however, their impact on future IOL design should be conditioned by further data, especially regarding posterior capsule opacification...
Posted by mehdi khanlari at 11:21 AM | Comments (0)
The Hoffer H Formula: A Work in Progress
Review of Ophthalmology March 2005
Hoffer’s new variation on the Holladay II, called the Hoffer H, uses the Holladay II formula but plugs in some new normal patient constants that Dr. Hoffer developed in his practice. Though the formula isn’t perfect, Dr. Hoffer says it may be useful in some cases. Here’s what went into the formula, and the results Dr. Hoffer has achieved with it so far.The good points: After using the formula on 400 eyes, Dr. Hoffer found that the mean absolute error (MAE) of the formula was best in short eyes with axial lengths less than 22 mm (5 percent of the patients) and in medium-long eyes between 24.5 and 26 mm (17 percent of the patients). Also, 21 percent of the patients were within 0.13 D of the predicted refractive error postop (See Figure 1), and 64 percent were within 0.5 D, values that were better than the other formulas.There are drawbacks, however. To start, the Hoffer H’s MAE was no better than the Holladay II or the SRK/T formulas (each around 0.45), and the Holladay II formula was better in terms of MAE in the largest single group of eyes, those between 22 and 24.5 mm in length (72 percent of the patients). Also, the SRK/T formula had the best MAE in the 6 percent of eyes in the sample longer than 26 mm.“I think the bottom line, and real benefit of the formula, is that the Hoffer H had the highest percentage of patients between ± 0.13 D of the predicted refraction. So, for implanting bifocal IOLs, or multifocals, where you need to get the patient to plano, your best chance will be with the Hoffer H,” says Dr. Hoffer.
Posted by mehdi khanlari at 11:08 AM | Comments (0)
Clinical implications of peripapillary atrophy in glaucoma
Current Opinion in Ophthalmology March 2005
Peripapillary chorioretinal atrophy is one among several morphologic variables to detect glaucomatous abnormalities. Ranking optic disc variables for the detection of glaucomatous optic nerve damage, peripapillary atrophy is a variable of second order. It is useful for the differentiation of various types of chronic open-angle glaucomas. In contrast to glaucomatous eyes, eyes with nonglaucomatous optic nerve atrophy, including eyes after arteritic anterior ischemic optic neuropathy, do not show an enlarged peripapillary atrophy
Posted by mehdi khanlari at 10:58 AM | Comments (0)
Anesthesia Methods
Review of Ophthalmology March 2005
Our panelists’ favorite ways to achieve anesthesia haven’t changed much since 2004, with topical gel becoming somewhat more popular, and retrobulbar blocks losing a little popularity. For this question, some surgeons chose more than one answer.Topical drops are used by 31 percent of respondents, down a little from the 34 percent of 2004’s survey, and 20 percent of the surgeons say they use a topical gel, a 5-percent increase from last year. The proportion of peribulbar-block proponents stayed relatively stable at 26 percent (vs. 27 percent last year), while retrobulbar-block users slipped a little to 21 percent from last year’s 28-percent mark. Nineteen percent of surgeons use intraocular lidocaine, and 7 percent use a topical combo. Ninety-eight percent of the surgeons who use topical say they also use IV sedation, and 2 percent use oral sedation Looking ahead, 18 percent of surgeons say they’re “somewhat” likely and 8 percent are “very” likely to begin using topical anesthesia within two years, with the remainder saying they’re either unlikely (55 percent) or very unlikely (18 percent) to do so.
Posted by mehdi khanlari at 10:41 AM | Comments (0)
2004 Phaco Report(3):Managing Astigmatism
Review of Ophthalmology March 2005
Our panelists’ preferred methods for correcting pre-existing astigmatism are limbal relaxing incisions (chosen by 36 percent of the surgeons) and the technique of placing the corneal entry incision on the axis of astigmatism (26 percent). Fourteen percent like to perform a postop refractive procedure, 3 percent use toric IOLs, and 21 percent chose a response of “other.”
Posted by mehdi khanlari at 10:33 AM | Comments (0)
2004 Phaco Report (2):Phaco Techniques
Review of Ophthalmology March 2005
• Micro-phaco. Though there is a lot of buzz about micro-phaco (a.k.a., bimanual phaco), only a small proportion of respondents, 11 percent, say they do it, and 71 percent say they’re unlikely to begin doing it within the next year. Twenty-nine percent, however, say they are at least “somewhat likely” to begin using the technique.
• Chopping gains popularity. Quadrant division is still the single most popular phaco technique, used by 45 percent of our respondents. This is a decrease of 10 percent, however, from last year. Phaco chopping is apparently on the rise, with the number of surgeons naming it their favorite technique rising 9 percent to a level of 28 percent this year. Ten percent of the surgeons prefer phaco flip/tilt, 8 percent like to divide the nucleus in two, 6 percent like sculpting and 4 percent prefer another method.
Posted by mehdi khanlari at 10:25 AM | Comments (0)
2004 Phaco Report (1):Placing the incision
Review of ophthalmology March 2005
This month, 80 surgeons, or 16 percent of our 500-surgeon sample, weighed in on the topic of cataract surgery techniques.This year, just over half of the respondents, 52 percent, declared clear-corneal incisions to be their favorite, compared to 41 percent who said the same in 2004’s survey. Scleral incisions seem to be losing favor with the panelists at the same time, with only 13 percent preferring them this year, compared to 22 percent last year. The proportion of limbal incision advocates has stayed about the same, at 34 percent, down only a percentage point from 2004. Surgeons say there are a number of reasons they like the clear-corneal wounds.
Posted by mehdi khanlari at 10:18 AM | Comments (0)
March 17, 2005
New hyperopia treatment
Eyeworld March 2005
Sutureless synthetic keratophakia (SSK) could become an alternative technique to treat hyperopia.The authors retrospectively analyzed the outcomes of SSK performed in 10 eyes of six patients. In each eye, a PermaVision intracorneal lens (Anamed, Lake Forest, Calif.) was implanted.Indications for implantation were +1 D to +6 D of spherical equivalent (SE) manifest refraction with less than 0.5 D of cylinder, a difference between manifest and cycloplegic refractions of less than 1 D, central keratometry readings between 41 D and 46 D, a minimum corneal thickness of 430 microns, and a pupil smaller than 5 mm under mesopic conditions.The flaps in eight eyes were created with the Hansatome microkeratome (Bausch & Lomb, Rochester, N.Y.) with a superior hinge. Before the flap was repositioned, the interface and the lens were allowed to dry for two minutes and balanced salt solution was applied to the flap to keep it from drying.The mean uncorrected visual acuity at six months was 0.85 (range 0.63 to 1) and the mean best corrected visual acuity (BCVA) was 0.99 (range 0.63 to 1.25), compared to a mean pre-operative BCVA of 0.96. No eye lost a line of visual acuity and 22% of eyes gained one or two lines of BCVA.The mean post-op keratometry at one month was 46.58 and 46.71 at six months, compared to 43.08 pre-operatively.
There were some intra-operative complications, including one case in which the lens was explanted because of acute decentration from an epithelial defect that occurred during flap creation. In another case, there was lens decentration, but recentration was performed 10 days post-operatively.Haze occurred in one case at eight months but resolved after two weeks of topical therapy.The preliminary results seemed to indicate that the use of a microkeratome with a thick base plate is important, according to the study, and that a nasal hinge helps prevent denervation and provide better lens centration.Nutrapore, the material from which PermaVision intracorneal lenses are made, has been well tolerated by stromal tissue in rabbits. Nutrapore is a microporous hydrogel formulation that allows permeability of the cornea’s metabolites
Posted by mehdi khanlari at 07:21 PM | Comments (0)
A LASIK application for fibrin glue
Eyeworld March 2005
After LASIK, any epithelial ingrowth that occurs has the tendency to recur.“The treatment for epithelial ingrowth has been to lift the flap and scrape out any epithelium that you can see from the underside of the flap as well as the stromal bed,” “But each time you lift the flap, you’re kind of opening a tunnel where the epithelium can migrate through.”An alternative method of this lifting and scraping process includes the placement of sutures around the edge of the flap to help block off the entrance to any epithelium.
“But placing corneal sutures through a LASIK flap is not an easy procedure,” “The flap is very delicate and there are a lot of potential problems with sutures in that setting.”As it turns out, fibrin glue is an effective substitute for suturing flaps, .After the flap is placed back down, use fibrin glue around the edge of the flap to seal it off and keep the epithelium from migrating underneath, he said.
Posted by mehdi khanlari at 07:12 PM | Comments (0)
Cataract Epithelialingrowth
Eyeworld March 2005
The problem of epithelial ingrowths are even less common in cataract surgery, traumatic corneal lacerations, and corneal transplants Cataract surgeons should take careful patient histories, checking for either a surgical procedure that left a chronic aqueous leak at the limbus or in the cornea or a laceration of the cornea. Sometimes such trauma either was repaired in a way that continued leaking or there was an implantation of epithelium in a highly disrupted eye during the injury.Such cases manifest themselves over time through the membrane and grow on the back surface of the cornea and iris.Another sign is less recognizable by most clinicians, Dr. Udell said, because the classic teaching states that an epithelial layer grows on the back surface of the cornea from the angle toward the center of the cornea.In addition, the epithelium grows in the angle and on the surface of the iris. One way to tell this is happening is the pupil starts to distort in shape and a fine glistening membrane may appear on the surface of the iris.“Another thing you can see in the anterior chamber — I have seen this after patients have transplants that have had downgrowths — is a large clumpy anterior chamber reaction,” Dr. Udell said. “So instead of looking like small white cells they look like little granular clumps of cells that are circulating in the anterior chamber. And that is a pretty good sign for downgrowth.”
One diagnostic test to confirm epithelium on the iris is use of the argon laser to lightly burn the surface of the iris, which typically would be non-reactive. If the epithelium turns white, instead of changing little, “you can pretty much confirm clinically that you have epithelium growing in the eye,” .
“Then, in order to define the extent of the epithelial growth in the eye, you apply light laser burns to the surface of the iris — sort of mapping out the area where the epithelium is,” he said. “You need to do that so you can decide what approach to take when trying to treat it, because if it is too extensive — more than 40% or 50% of the iris and angle — it is a daunting procedure to try to remove it surgically.”Iris cysts and localized involvement are managed with en-bloc, or laser deflation of the cysts, and adjunctive photocoagulation
Posted by mehdi khanlari at 06:55 PM | Comments (0)
Epithelial ingrowths: Beware the warning signs
Eyeworld March 2005
One of the most common threats from epithelial incursions occur in post-operative LASIK patients. A surgeon with extensive experience in such cases, Edward J. Holland, M.D said surgeons can pre-operatively identify those most likely affected with the abnormal growth.
Patients with pre-existing epithelial problems are at most risk for epithelial ingrowths, including those with epithelial basement membrane dystrophy.Holland urges surgeons to perform a careful slit lamp examination looking for obvious signs of epithelial basement membrane dystrophy also known as map dot fingerprint dystrophy. This degeneration of the epithelium can cause microcysts or macrocysts of the epithelium with thickened lines of the basement membrane and sheets of thickened basement membrane referred to as maps.
The obvious patient, Dr. Holland said, is pretty easy to identify. But patients with subtle signs, such as microcysts in the epithelium, are a bit more challenging.Other patients at risk are those that develop epithelial defects at the edge of the flap. This will “significantly increase your risk of epithelial ingrowth,” he said. Anything clinicians can do to increase the adherence of loose or abnormal epithelium will reduce the risk of epithelial ingrowth.
Intra-operatively, Dr. Holland suggests an anterior stromal puncture in the affected area on the peripheral cornea as well as in the peripheral epithelium of the flap, to help the loose epithelium become more adherent. Puncturing multiple small areas through the basement membrane with a 25-gauge needle will “markedly reduce the problems of loose epithelium and often the next day with this procedure we see that area of loose epithelium is completely healed,” .
Posted by mehdi khanlari at 06:42 PM | Comments (0)
March 14, 2005
Artisan iris-claw phakic intraocular lens followed by laser in situ keratomileusis for high hyperopia
JCRS FEB 2005Alicante, Spain;To evaluate safety, efficacy, predictability, stability, complications, and patient satisfaction after Artisan phakic IOL followed by LASIK for the correction of high hyperopia.
Conclusions:The combination of Artisan phakic IOL implantation and LASIK safely, predictably, and effectively reduced high hyperopia. A loss of 1 line of BCVA should be expected in about one third of eyes implanted with this IOL. Halos and glare at night remain a potential problem.
Posted by alireza habibollahi at 10:49 PM | Comments (0)
Surgical treatment of a dislocated intraocular lens–capsular bag–capsular tension ring complex
JCRS FEB 2005
We describe a surgical technique for managing late dislocation of an intraocular lens–capsular bag–capsular tension ring (IOL–CB–CTR) complex. Two 10-0 polypropylene sutures are placed transsclerally over and under the CTR through the anterior and posterior capsules to capture the CTR, which then is retracted and sutured through the sclera. The same maneuver is performed 180 degrees away. This simple, easy, effective procedure can be performed with a small corneal incision and does not require extraction of the IOL–CB complex. Although the CTR does not completely prevent IOL–CB dislocation, it provides the possibility of suturing the IOL–CB to the sulcus without replacing the IOL.
Posted by alireza habibollahi at 10:49 PM | Comments (0)
Change in pupil size after implantation of an iris-fixated toric phakic intraocular lens
JCRS FEB 2005
Mana Tehrani,Mainz, Germany.
To evaluate the changes in pupil size after implantation of an iris-supported toric phakic intraocular lens (TPIOL) for correction of myopia and hyperopia with astigmatism.
22 myopic eyes and 9 hyperopic eyes were included in the study. The mean age of the 2 groups was 34 years and 40 years, respectively. The scotopic pupil size was measured with a handheld infrared pupillometer (Colvard, Oasis Medical) before and 6 months after implantation of the TPIOL. All examinations were performed under scotopic conditions after 2 minutes of dark adaptation with the fellow eye covered. Intraindividual comparisons were made between preoperative and postoperative pupil sizes. The relationship between implanted IOL power and postoperative pupil width in each group was studied to determine whether lens magnification could lead to misinterpretation of the results. The difference between horizontal and vertical postoperative pupil diameters was assessed in eyes with horizontally aligned IOLs to determine the potential mechanical effect of the TPIOL on pupil size.
Conclusions
The scotopic pupil diameter decreased by a mean of 1.1 mm in myopic eyes and 1.0 mm in hyperopic eyes after implantation of the iris-supported TPIOL. Postoperative pupil size was not related to IOL power, patients' emotional states, or other factors. The slightly smaller pupil diameter in the axis of enclavation suggests that this fixation method restricts pupil size under scotopic conditions, which could reduce the incidence of postoperative photic phenomena.
Posted by alireza habibollahi at 10:38 PM | Comments (0)
Standardized arcuate keratotomy for postkeratoplasty astigmatism
JCRS FEB 2005
London, United Kingdom.To assess the effect of standardized, paired arcuate keratotomy (AK) on the change in astigmatism in postkeratoplasty eyes.Methods:A retrospective review was conducted of 20 eyes of 19 patients having the same AK procedure regardless of the magnitude of the preoperative astigmatism. Each eye had a pair of 60-degree arc length incisions placed in the corneal stroma. The incisions were 600 μm deep and 6.0 mm apart. The preoperative and postoperative refractions and complications were analyzed. Astigmatic change was analyzed without regard to axis, as surgically induced refractive change, and using a modified polar plot of change in astigmatism.
Conclusions
In postkeratoplasty eyes, the change in the magnitude of astigmatism induced by standardized AK was proportional to the preoperative magnitude of astigmatism. Arcuate nomograms for congenital astigmatism have no role in the management of astigmatism in postkeratoplasty eyes.
Posted by alireza habibollahi at 10:31 PM | Comments (0)
Transepithelial PRK-Mitomycin-C for complicated LASIK flaps
JCRS FEB 2005
Illinois, USA,To evaluate the efficacy of transepithelial PTK/PRK with prophylactic mitomycin-C for the treatment of refractive errors and maintenance of corneal clarity following flap complications in LASIK.Methods:Ten eyes with LASIK flap complications had transepithelial PTK/PRK for correction of ametropia. Mitomycin-C 0.02% was applied to the stroma for 2 minutes following laser ablation. Post-op UCVA,BSCVA, refractions, and SLE were obtained.
Results
Preoperatively, the mean UCVA was 20/400 (range 20/40 to counting fingers), the mean BSCVA was 20/28.5, and the spherical equivalent refractive errors ranged from +4.00 to −10.75 diopters (D). After the procedure, the mean UCVA was 20/28, the mean BSCVA was 20/21, and the spherical equivalent refractive errors ranged from +0.37 to −1.00 D. The mean follow-up ranged from 8 to 28 months. No patient experienced delayed reepithelialization, haze, or other signs of toxicity.
Conclusion;Mitomycin-C can be a useful adjunctive therapy for the prevention of haze when applying surface excimer laser therapy to a cornea following LASIK flap complications.
Posted by alireza habibollahi at 09:51 PM | Comments (0)
Risk Factors of Retinopathy of Prematurity in Premature Infants Weighing Less Than 1600 g
American Journal of Perinatology
This study confirms several risk factors recognized in previous statistical analyses. Sepsis is the most significant factor contributing to ROP. Vitamin E was proven to be effective in prophylaxis of development of ROP. The possibility of development of ROP could not be excluded in infants with gestational age > 32 weeks...
Posted by mehdi khanlari at 06:37 AM | Comments (0)
Cataract surgery in patients with Fuchs' corneal dystrophy: Expanding recommendations for cataract surgery without simultaneous keratoplasty
Ophthalmology March 2005
Conclusions: To avoid unnecessary cost and delay in visual rehabilitation, we suggest changing the current recommendations for an initial triple procedure for eyes with preoperative pachymetry measurements of >600 micro m. Our data suggest that current cataract removal techniques allow for excellent visual rehabilitation in patients with Fuchs' dystrophy who have a preoperative corneal thickness of >600 micro m, and we suggest that preoperative pachymetry measurements of >640 micro m may be a better guideline...
Posted by mehdi khanlari at 06:20 AM | Comments (0)
March 11, 2005
Can aqueous humor be diverted to the ocular surface and substitute for tears in very dry eyes?
Digital Journal of Ophthalmology 2005
In very dry eyes from any etiology, there is a need for near-continuous fluid supply to the ocular surface. Here is presented a patient with severe dry eyes who had a double-tubed valve shunt implanted to divert the aqueous humor to the lower lid fornix, thereby wetting the eye. Such arrangement has previously been used in eyes with keratoprosthesis and glaucoma, without resulting in infection.
A 67 year old woman had been severely incapacitated with pain and photophobia for many years. Tear menisci were virtually absent, Schirmer values were repeatedly zero, and vision was reduced in one eye. Etiology seemed to be scarring of lacrimal gland ductules caused by vernal catarrh. The shunt was implanted without complications, immediately resulting in wetting. After 5 months the eye is totally quient and comfortable, with 20/25 vision and mild epiphora due to obstructed canaliculi. The tube in the lower fornix is rarely felt. Antibiotic drops are given twice daily and no infection has occurred.
Conclusion:So far the patient has done well with a totally quiet and wet eye. The only complication has been epiphora. If the long-term risks are low, this principle may be of value in end-stage dry eyes such as in autoimmune diseases, chemical burns, and trachoma.
Posted by afarahi at 09:04 PM | Comments (0)
Botulinum toxin treatment for acute traumatic complete sixth nerve palsy
Eye,March,2005
We retrospectively reviewed patients treated for acute unilateral complete sixth nerve palsy caused by head injury during a 10-year period (between March 1993 and February 2003) in our hospital. The BTX treatment group was defined as patients who received BTX injection within 3 months of injury. Patients who presented within 3 months of trauma, and had no previous BTX injection or surgery were enrolled as the conservative treatment group. Comparison of the patient demographics, palsy characteristics, angle of deviations, and recovery rates were made between the two groups.
In all, 33 patients were enrolled by our inclusion criteria. Of these, 19 patients were treated conservatively, and 14 patients were treated with BTX. A total of 79% of our patients presented with abduction deficit of grade -5. The results showed that there was no significant difference in the outcome for the two groups based on age, gender, time to presentation, severity, and initial angle of deviation. The BTX group had a higher recovery rate than the conservative treatment group (64.3 vs 26.3%, P=0.028). Among 26 patients with grade -5 abduction deficit, the recovery rate was higher in the BTX-treated patients than in the conservatively treated patients, which had no statistical significance (50 vs 18.8%, P=0.09).
Conclusion: BTX facilitates recovery of acute traumatic complete sixth nerve palsy in severely injured patients.
Posted by afarahi at 08:44 PM | Comments (0)
Ocular motility findings in chronic progressive external ophthalmoplegia
Eye,March,2005
25 patients with chronic progressive external ophthalmoplegia were studied.A total of 23 (92%) patients had an exo-deviation, with six (26%) of those having an associated vertical deviation: 12 patients were binocular. Of the 13 patients with a manifest deviation seven had diplopia and six had suppression. Of all paired extra-ocular muscles (EOM), 68% had symmetry of movement within 5° of each other.
Conclusion :Almost all patients had an exo-deviation. Diplopia was more common than expected. The majority of patients had symmetry of EOM limitation.
Posted by afarahi at 08:40 PM | Comments (0)
March 10, 2005
Determining in vivo biomechanical properties of the cornea with an ocular response analyzer
Journal of Cataract & Refractive Surgery Volume 31, Issue 1 , January 2005, Pages 156-162
To study the results of an ocular response analyzer (ORA) to determine the biomechanical properties of the cornea and their relationship to intraocular pressure (IOP).
The ORA (Reichert) makes 2 essentially instantaneous applanation measurements that permit determination of corneal and IOP effects.
Results
Measurements of several populations indicate that corneal hysteresis, a biomechanical measure, varied over a dynamic range of 1.8 to 14.6 mm Hg and was only weakly correlated with corneal thickness (r2 = 0.12); this is related to the observation that some subjects with relatively thick corneas have less-than-average corneal hysteresis. Corneal hysteresis changes diurnally, presumably as a result of hydration changes. Keratoconus, Fuchs' dystrophy, and post-LASIK patients demonstrated low corneal hysteresis.
Conclusion
The corneal hysteresis biomechanical measure may prove valuable for qualification and predictions of outcomes of refractive surgery and in other cases in which corneal biomechanics are important.
Posted by mmiraftab at 06:19 PM | Comments (0)
Acute corneal hydrops treated by intracameral injection of perfluoropropane (C3F8) gas
American Journal of Ophthalmology Volume 139, Issue 2 , February 2005, Pages 368-370
To report a case of acute hydrops with intrastromal cleft in a patient of keratoconus with associated Marfan's syndrome, treated with intracameral injection of perfluoropropane (C3F8) gas.A nonexpansile concentration of perfluoropropane gas (0.2 ml) was injected intracamerally in the operating room under aseptic precautions.There was complete and rapid resolution of corneal edema.Intracameral perfluoropropane gas in nonexpansile concentration may be a useful modality for treatment of corneal edema in acute corneal hydrops.
Posted by mmiraftab at 06:14 PM | Comments (0)
Alcohol- vs Hypertonic Saline–Assisted Laser-Assisted Subepithelial Keratectomy
Arch Ophthalmol Vol. 123 No. 2, February 2005
Methods Fifty-two consecutive eyes (26 patients) were randomized to HS-LASEK (30 eyes) and A-LASEK (22 eyes) groups. The patients’ eyes were examined, refracted, and photographed at 1 day, 5 days, 2 weeks, and 1 month postoperatively by a masked physician. Corneal topography and confocal examination were performed before and 1 month after surgery.
Main Outcome Measures The predictability, accuracy, and visual recovery of HS-LASEK vs A-LASEK in the first postoperative month.
Results The accuracy of HS-LASEK was similar and sometimes better than A-LASEK. Two weeks after surgery, 17 eyes (57%) in the HS-LASEK group and 10 eyes (46%) in the A-LASEK group were within ± 0.5 diopter of the intended refractive correction (P<.05). At all time points eyes in the HS-LASEK group had better best-corrected visual acuity than eyes in the A-LASEK group, although the uncorrected visual acuity was similar. Eighteen (61%) of the HS-LASEK–treated eyes and 12 (55%) of the A-LASEK–treated eyes had an epithelial defect after surgery. The HS-LASEK–treated eyes had significantly larger epithelial defects. The resolution of the defects was faster in the HS-LASEK–treated eyes (mean ± SD, 4.5 ± 0.4 days vs 5.8 ± 0.2 days, P = .002). The subepithelial scar was thicker in A-LASEK–treated eyes.
Conclusions Hypertonic saline–assisted LASEK provides good postoperative accuracy, safety, and a similar rate of complications. In view of recent evidence regarding the epithelial toxic effects of alcohol, HS-LASEK might be a better treatment alternative.
Posted by mmiraftab at 06:02 PM | Comments (0)
Two cases of AlphaCor surgery performed using a small incision technique
Clinical & Experimental Ophthalmology Volume 33 Issue 1 Page 10 - February 2005
The authors have evaluated the AlphaCor artificial cornea (previously Chirila KPro) in human patients since 1998, utilizing an intrastromal technique requiring extensive corneal lamellar dissection and recommending conjunctival flaps in all cases. Recent availability of low-profile instruments has facilitated a simpler technique, which was first evaluated in two subjects followed for over 1 year prior to recommending the technique for wider adoption. The new technique is presented and illustrated herein, and its benefits and limitations compared with the traditional AlphaCor implantation are discussed.
Posted by mmiraftab at 05:51 PM | Comments (0)
March 08, 2005
Severe anaphylactic reaction after intracameral antibiotic administration during cataract surgery
JCRS Feb 2005
Many practitioners these days use intracameral, low-concentration antibiotics during cataract surgery. While previously there have been no reported life-threatening complications, now investigators have presented a case that involves an anaphylactic reaction after intraocular administration of an antibiotic agent during cataract surgery. The case involved a 68-year-old man with bilateral posterior subcapsular cataracts. The patient had an allergy to oral ampicillin (various manufacturers). On the first eye, no antibiotic was administered intra-operatively and the patient underwent uneventful phacoemulsification. On the second eye, however, practitioners injected 1 mg of cefuroxime (0.1 ml in a 10 mg/ml concentration, Ceftin, GlaxoSmithKline, London) into the anterior chamber at the end of the case. Within five minutes, the patient reported that he was not feeling well. His eyelid began to swell and his pressure fell to 70 mm Hg over 40 mm Hg. The patient also began to have difficulty breathing. Immediately, the anesthetist intravenously administered 500 mg of methylprednisolone (Medrol, Pfizer, New York), 10 mg of dexchlorpheniramine (various manufacturers), 50 mg of ranitidine (various manufacturers), 30 mg of ephedrine (various manufacturers) in 30 boluses of 10 mg at 10 minute intervals, and up to three liters of Ringer’s lactate solution (Baxter Healthcare Ltd., Thetford, Norfolk, U.K.). Within 20 minutes, the patient had recovered from episode and was admitted for observation.
Posted by mehdi khanlari at 09:49 PM | Comments (0)
SCIENTISTS REGENERATE OPTIC NERVE FOR THE FIRST TIME
Review of Ophthalmology
Scientists at the Schepens Eye Research Institute, Harvard Medical School, have regenerated a damaged optic nerve for the first time. The process, which was conducted in laboratory mice, is described in the March 1, 2005 issue of Journal of Cell Science. The research, led by Dr. Dong Feng Chen, is aimed at determining why CNS tissue in mammals loses its ability to regenerate after injury and at finding ways to reverse this process. Earlier research by this team showed that several processes seemed to "lock up" the optic nerve’s ability to regenerate. One such "lock" was the turning off of a specific gene that activates growth and regeneration. Another, the team believes, could be a "scar" on the brain that is created shortly after birth by glial cells; this scar may present a barrier to regeneration. In their current research, the investigators tested "keys" to unlock regeneration. The first was to develop a mouse model in which the growth and regeneration gene is always turned on; the second was to use a mouse line that has mutations of glial-specific genes that can reduce glial "scars." They found that the combination of the turned-on regeneration gene and the mutation of "glial specific genes" caused the optic nerves to return to an embryonic state and stimulated rapid and vigorous regeneration of the optic nerve within days. Dr. Chen and her colleagues have yet to determine whether these regenerated nerves are functional and actually cause the mice to see again, but they believe that the results hold great promise for regenerating not only optic nerves, but also other tissues of the CNS.
Posted by kjalali at 09:33 PM | Comments (0)
Posterior keratoplasty associated with less postop glaucoma
OSN March 2005
Penetrating keratoplasty was associated with a higher incidence of glaucoma than a microkeratome-assisted posterior keratoplasty procedure, according to a retrospective study. Dr. Ayyala said that by not disturbing the angle, MAPPK reduced the incidence of postoperative glaucoma. In the PK group, 30% of patients with no previous glaucoma developed glaucoma after the surgery, he said.
Posted by mehdi khanlari at 09:16 PM | Comments (0)
Thin LASIK flap, nasal hinge associated with fastest return of corneal sensitivity
OSN March 2005
A thin LASIK flap with a nasally placed hinge was associated with the most rapid recovery of corneal sensitivity in a clinical study. Both flap thickness and hinge location were important factors in the rate of return of corneal sensitivity after LASIK, the study authors said.Corneal sensitivity returned to preoperative levels after 5.8 months in the superior-hinge, thick-flap group; after 5.4 months in the superior-hinge, thin-flap group, after 4.4 months in the nasal-hinge, thick-flap group, and after 3.7 months in the nasal-hinge, thin-flap group. The differences were statistically significant between the two nasal hinge groups, but not between the superior-hinge groups. Sensitivity was higher in the hinge area than other areas at all follow-up points.
Posted by mehdi khanlari at 09:13 PM | Comments (0)
Evaluation of Image Artifact Produced by OCT of Retinal Pathology
Review of Ophthalmology
Optical coherence tomography (OCT) scan artifacts are seen surprisingly frequently, adversely affect retinal thickness measurements in a high proportion of cases and are diagnosis-dependent. The researchers conducted a retrospective observational case series aimed at determining the frequency and type of optical coherence tomography (OCT) fast macular thickness map (FMTM) scan artifacts, and whether these artifacts depend on patient diagnosis, demographics and ocular therapy. Researchers determined the relationships between OCT scan artifacts and ocular diagnosis, ocular treatment and patient demographics. They used logistic regression to relate OCT scan artifacts simultaneously with ocular diagnosis and treatment. Retinal scan artifacts, though not observed in normal eyes, were identified frequently in eyes with macular pathology. Artifacts were observed in 43.2 percent of all scans; of these, an erroneous retinal thickness measurement was obtained in 62.2 percent. Six types of OCT surface map artifacts were observed. Of these, inner and outer retinal misidentification, degraded image artifact and "off center" artifact were significantly associated with central thickness calculation errors. Neovascular age-related macular degeneration (AMD), full-thickness macular hole and photodynamic therapy were all associated with increased artifact. The authors believe that recognition of these artifacts will improve retinal thickness measurement accuracy, and will prevent faulty treatment decisions that are based on inaccurate retinal thickness measurements.
Posted by kjalali at 08:52 PM | Comments (0)
Ocular higher-order aberrations in eyes with supernormal vision
American Journal of Ophthalmology Volume 139, Issue 2 , February 2005, Pages 225-228
Ocular HOAs were examined across a naturally dilated pupil with a diameter ≥ 6.0 mm in 70 eyes of 35 subjects with ≥ 20/15 UCVA (mean age 24.3 years ± 7.7 [SD]) using the Nidek OPD scan wavefront aberrometer. Root-mean-square (RMS) values of HOA, total spherical aberration (TSA), total coma (TC), and total trefoil (TT) were analyzed. Correlation analysis was performed to assess the association between ocular HOAs and age and the correlation of HOAs between right and left eyes.
Results
Mean RMS values were 0.334 ± 0.192 μm for HOA, 0.110 ± 0.077 μm for TSA, 0.136 ± 0.081 μm for TC, and 0.268 ± 0.220 μm for TT. There were no significant differences in the mean values of HOA, TSA, TC, and TT between right and left eyes. The Pearson correlation coefficient between right and left eyes for TSA was 0.764 (P<.0001). No significant correlation was found between right and left eyes for HOA, TC, and TT. No significant correlation was found between each of the ocular aberrations and age.
Conclusions
The amount of ocular HOAs in eyes with natural supernormal vision is not negligible, and is comparable to the reported amount of HOAs in myopic eyes.
Posted by mmiraftab at 03:51 PM | Comments (0)
March 07, 2005
Corneal modeling of keratoconus by conductive keratoplasty
J Cataract Refract Surg. 2005 Jan
Alio JL, Spain.We evaluated the effect of conductive keratoplasty (CK) applications for corneal modeling to treat keratoconus or post-laser in situ keratomileusis (LASIK) corneal ectasia in 3 patients. Treating keratoconus with CK applications resulted in more regular topography with visual improvement.
Posted by alireza habibollahi at 11:37 PM | Comments (0)
Conductive keratoplasty to correct residual hyperopia after corneal surgery.
JCRSJAN 2003
Australia.Conductive keratoplasty (CK) is an electrical-current-based technique for steepening the central cornea to reduce low to moderate hyperopia. We report 4 patients who had CK to correct hyperopia after laser in situ keratomileusis (LASIK) and were followed for at least 6 months. An overcorrection was noted after the CK procedure in all patients, but no sight-threatening complications arose. Conductive keratoplasty appears to be safe and well tolerated after LASIK. However, the algorithms should be modified to increase the predictability of the CK procedure in previously treated eyes.
Publication Types:
Case Reports
Posted by alireza habibollahi at 11:03 PM | Comments (0)
Cataract surgery prophylaxis regimen
OSN Feb 2005
At Issue posed the following question to a panel of experts:
“What is your preferred prophylactic regimen for cataract surgery?”
Jorge L. Alio: Four days prior to the surgery, the patient is prescribed a special eyelid soap gel that needs to be applied twice a day, immediately after waking up in the morning and before going to bed in the evening. The gel contains a neutral pH soap and antiseptic.Three days before surgery, the patient uses ofloxacin 0.3% eye drops twice a day (early morning and before going to bed). The patient is instructed to clean his spectacles, if he uses them, with the soap and to report any discomfort, pain or redness of the eye the day of the surgery.Just before entering the operating room, we wash the eye extensively with a solution of 50% povidone-iodine diluted in saline.At the end of surgery, an intraocular injection of 250 µg (1% dilution on 0.1 cc) of cefuroxime is performed. THe eye is rinsed again with 50% povidone-iodine solution.Postoperative prophylaxis includes the use of the same antibiotic and topical steroids.High-risk patients such as diabetics, patients with simple occlusions of the lacrimal pathways or ocular surface disorders, or patients with poor hygiene habits or who do not have adequate hygiene at home are sometimes treated after surgery with oral ciprofloxacin, one capsule (500 mg) twice a day for 5 days. This is done in less than 0.5% of cases.
Posted by mehdi khanlari at 08:00 AM | Comments (0)
March 06, 2005
Device for continuous IOP monitoring in development
SNOWBIRD, Utah — An implantable microsensor that montiors IOP throughout the day may increase physicians’ understanding of glaucoma, according to a speaker here.A single IOP measurement in the office does not provide adequate information about IOP behavior,” said Leon G. Partamian, MD, here at the American Glaucoma Society annual meeting.He said IOP levels vary throughout the day, and current IOP measuring devices, such as Goldmann tonometry, create only a snapshot of the patient’s IOP.Dr. Partamian and colleagues at the Jules Stein Eye Institute are developing a device that monitors IOP through two coils placed a distance apart on the cornea. The researchers observed accurate and consistent measurements with a prototype in pressure-chamber tests, he said.Our prototypes had resolutions of 1.2 mm Hg to 1.4 mm Hg with routine test equipment,” Dr. Partamian said, calling the results to date “promising.”
Posted by mmiraftab at 11:04 PM | Comments (0)
March 04, 2005
Model for nonectatic increase in posterior corneal elevation after ablative procedures
Hong Kong, China.To evaluate the response of the posterior cornea after uneventful LASIK with scanning-slit videokeratography using the change in elevation as a measure of biomechanical remodeling.
Conclusions
Increases in central posterior corneal elevation after LASIK appear to be dominated by backward peripheral corneal swelling into the anterior chamber rather than forward “bulging” of the central posterior cornea. This is consistent with stable remodeling of the corneal shape due to a surgically induced change in structure and fluid balance, rather than an ectatic event.
Posted by alireza habibollahi at 07:03 PM | Comments (0)
Octreotide (Long-Acting Release Formulation) Treatment in Patients with Graves’ Orbitopathy: Clinical Results of a Four-Month, Randomized, Placebo-Controlled, Double-Blind Study
The Journal of Clinical Endocrinology & Metabolism Vol. 90, No. 2
There are few effective, safe modalities for the management of Graves’ ophthalmopathy (GO), a cell-mediated immune comorbidity of thyroid disease. Somatostatin analogs inhibit lymphocyte proliferation and activation, and accumulate in the orbital tissue of patients with GO. A double-blind, placebo-controlled study of a long-acting somatostatin analog [16 wk of long-acting release formulation of octreotide (octreotide-LAR)] was conducted in 51 patients with mild active GO with the aim of preventing deterioration and precluding the need for more aggressive therapeutic modalities, such as glucocorticoids or radiotherapy. No treatment effect was observed for the primary end point (a composite parameter defining the outcome as either success or failure on the basis of changes in class/grade of the severity index and Clinical Activity Scale of GO). The Clinical Activity Scale score was reduced for patients treated with octreotide-LAR, but without any significant difference with respect to patients receiving placebo. However, octreotide-LAR significantly reduced proptosis (as measured by exophthalmometry). Additional studies are warranted to define the benefit to risk ratio of the somatostatin analogs in this indication.
Posted by afarahi at 06:53 PM | Comments (0)
Response of the posterior corneal surface to M.LASIK
JCRS JAN 2005
Hong Kong SAR, China,To and determine whether residual stromal bed thickness or treatment magnitude is predictive of the posterior corneal surface elevation after uneventful LASIK.
Orbscan I were performed on 1124 patients before and 6 months after LASIK ,BFS over the central 9.0 mm region of the posterior corneal surface before and after treatment was compared. The location and magnitude of the 1.0 mm diameter region of highest elevation above the BFS for the central 4.0 mm diameter zone were calculated before and after treatment and compared using a paired t test. Stepwise regression was used to model the best predictors of the posterior radius of the BFS and the central elevation of the corneal surface above the BFS before and after treatment.
Conclusions
No eye was diagnosed with corneal ectasia at the time of the 6-month postoperative visit. After LASIK, there was a decreased radius of curvature for the BFS of the posterior corneal surface, with the highest elevation point located paracentrally. These findings are similar to the anterior corneal surface changes observed in corneal ectasia after LASIK but smaller in magnitude.
Posted by alireza habibollahi at 06:44 PM | Comments (0)
Maternal smoking associated with less myopia in children
Eyeworld March 2005
Children with mothers that smoke cigarettes may have a lower prevalence of myopia, a new study suggests.Research conducted in Singapore, in cooperation with researchers from the University of Pennsylvania School of Medicine, Philadelphia, set out to examine the relationship between exposure to passive parental smoke and myopia in Chinese children in Singapore.The number of smoking mothers was quite low, so further studies are needed to test any possible association of passive smoking with myopia.The study, published in the British Journal of Ophthalmology, showed that while there was no “consistent evidence” of a connection between parental smoking and refractive error, children whose mothers smoked cigarettes seemed to have a lower prevalence of myopia.Reasons for the mother-child link could be due to the amount of time children spend with their mothers versus their fathers, said Dr. Stone. But this is still speculative. It still needs to be determined whether a mother’s second-hand smoke is the primary factor, intermediate factor, or whether maternal smoking is a just a signal for other behavioral, social, or genetic factors that directly affect refractive development.The authors hypothesized that because of the pharmacology of nicotine, a relationship between myopia and passive cigarette smoking could provide pilot evidence for involvement of nicotinic cholinergic receptors in human refractive development.Nicotine binds to receptors found in the central nervous system and retina.during their child’s lifetime for an average of 7.5 years. There were no trends between paternal smoking and refractive error.But, after controlling for age, sex, school, mother’s education, and mother’s myopia, children exposed to their mothers second-hand smoke any time during their lifetime had more “positive” refractions (adjusted mean –0.28 D versus –1.38 D) compared with children whose mothers did not smoke (P=0.012).Research has shown that antagonists acting at neural nicotinic acetylcholine receptors inhibit experimental myopia.Therefore, although this was the first study of its kind, it had been hypothesized that exposure to nicotine in cigarette smoke may activate nicotinic cholinergic receptors and induce shifts in refraction.
Posted by mehdi khanlari at 06:19 AM | Comments (0)
The chopstick technique: A case study
Eyeworld March 2005
Dr. Sethi and coauthors described the chopstick technique in the case of a 60-year-old man that suffered a torn posterior capsule from a phacoemulsification probe. This injury resulted in an impending dropped nucleus.
Here are the details of the surgery:
• The probe was gently removed while an ophthalmic viscosurgical device (OVD) was injected into the anterior chamber to avoid sudden decompression;
• The continuous curvilinear capsulorhexis was released with a Vannas scissors;
• A 3.0 mm pars plana incision was made behind the limbus, and a Sinskey hook was inserted from the pars plana with the tip pointing upward to support the nucleus from behind;
• A second Sinskey hook was inserted into the anterior chamber from the side-port incision, and the tip was buried in the nucleus. One hook gripped the nucleus while the other one maintained support from behind;
• Gripped between the two instruments, the nucleus was brought out of the capsular bag and into the anterior chamber;
• With posterior support to the nucleus maintained from behind with the first instrument, the incision was enlarged for nucleus removal;
• The second instrument was then removed from above and brought under the nucleus. The pars plana instrument was brought into the chamber and embedded in the top of the nucleus;
• The nucleus was brought out of the section by holding it in a chopstick grip between the two Sinskey hooks under OVD cover. “The goal was to avoid pressure on the eye and prevent further vitreous loss,” the authors wrote;
• An anterior vitrectomy with a coaxial cutter was performed through the wound; and
• After vitreous and cortical matters were removed from the anterior chamber, an IOL with a 6.5 mm optic was implanted in the sulcus over the anterior capsule. The incision was then closed with a 10-0 nylon shoelace structure.
Posted by mehdi khanlari at 05:25 AM | Comments (0)
March 02, 2005
Epilepsy drug increases visual field defects, study confirms
England — An anti-epilepsy drug awaiting regulatory approval in the United States appeared to cause visual field defects in more than 40% of patients, a long-term study here found. Patients with epilepsy who were prescribed vigabatrin had a high incidence of asymptomatic visual field defects, according to the study.Published in the August issue of Journal of Neurology, Neurosurgery and Psychiatry, the study confirms earlier published findings of ocular side effects from the drug. Previous studies indicated vigabatrin causes visual field constriction in about 30% of patients; this study put the figure at 43%. The defects are in most cases peripheral and therefore asymptomatic. Previous reports have indicated that vigabatrin, indicated as a monotherapy for the treatment of infantile spasms, increases the concentration of gamma-amino butyric acid in the brain and retina and is associated with a number of ocular side effects. The drug has been approved in more than 60 countries for the adjunctive management of partial epilepsy.The authors of the new report noted that in 75 patients who had stopped using vigabatrin because of visual field abnormalities, seizure control was no different or had improved on other medication in 66 patients (88%) and had deteriorated in only seven (9%).
from osnsupersite posted by Dr.Mtaherzadeh
Posted by mtaherzadeh at 12:43 AM | Comments (0)
Study: orbital radiotherapy did not improve Graves' ophthalmopathy
Orbital radiotherapy demonstrated no benefit in patients with mild or moderately severe Graves' ophthalmopathy in a study conducted here. The randomized, double-blind study showed there was no difference between treated and untreated eyes after either 3 months or 6 months. The researchers then studied whether treatment earlier or 6 months later in the course of the disease made a difference, and again they found no correlation.The study excluded patients with very severe ophthalmopathy that has damaged the optic nerve.
f rom osnsupersite posted by Dr.M taherzadeh
Posted by mtaherzadeh at 12:37 AM | Comments (0)
One or more lesions in ON mean increased risk for MS
Patients with acute optic neuritis who have one or more brain lesions on baseline MRI have a more than 50% chance of progressing to multiple sclerosis over a period of 10 years, according to long-term results of a major study.The Optic Neuritis Study Group (ONSG) found that higher numbers of lesions do not seem to affect the risk of progression.Previous 5-year study outcomes revealed a 30% overall risk of developing MS after acute optic neuritis. Ten-year outcomes determined an overall risk of 38%; 12-year outcomes determined 40%. In the most recent data, 160 patients who had one or more typical lesions on baseline MRI had a 56% risk of developing MS; in those without lesions the risk was 22%.
ONSG authors said such data are a “critical input for estimating a patient’s 10-year multiple sclerosis risk and for weighing the benefit of initiating prophylactic treatment at the time of acute optic neuritis or other initial demyelinating events in the central nervous system.”
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from osnsupersite posted by Dr.M taherzadeh
Posted by mtaherzadeh at 12:11 AM | Comments (0)
March 01, 2005
Bleb needling an option before repeat trabeculectomy is attempted
OSN 2005
Bleb needling an option before repeat trabeculectomy is attempted
Careful management of the patient intra- and postoperatively may reduce bleb failure, according to one surgeon.Needling a previously viable bleb conserves the conjunctiva and allows faster recovery and fewer complications than repeat trabeculectomy, often with similar results. In-office bleb needling is a shorter, less complicated procedure than a repeat trabeculectomy.“Needling at the slit lamp may be a reasonable step in most situations where prior bleb function was present,” Dr. Ruderman said in his presentation. Studies of bleb needling have reported varying success rates, ranging from 30% to 94%.
Complications reported in the Broadway study included hyphema (3%), hypotony (2%) and recurrent bleb leak (1%). Other studies, however, have reported more serious complications, such as suprachoroidal hemorrhage, malignant glaucoma and endophthalmitis, he said.
Avoiding bleb failure
Early bleb failure generally occurs within the first 2 to 6 postoperative weeks. Factors that can contribute to failure include previous conjunctival surgery, inflammation, aphakia, neovascular glaucoma and long-term use of glaucoma drop medications. Signs that the bleb is failing include thickening and vascularity of the bleb, a gradual increase in IOP, loss of microcysts and the eventual flattening of the bleb.
In patients predisposed to bleb failure, some early management strategies may help prevent failure and may prevent returning for another surgical procedure.
from osnsupersite posted by Dr.M taherzadeh
Posted by mtaherzadeh at 11:49 PM | Comments (0)
Dynamic corneal imaging could increase refractive corneal surgery predictability
A diagnostic tool called dynamic corneal imaging may allow earlier diagnosis of corneal disease and may increase the predictability of refractive corneal surgery, investigators suggest.In dynamic corneal imaging, videokeratography is used to record the response of the cornea to sequential indentation with electronically controlled “microprecision motors. The measurement technique was performed in 187 eyes of 103 patients who had clinically healthy corneas, distinct keratoconus or previous refractive surgery. The technique quickly evaluated artificially and reversibly induced changes in corneal topography in a clinical setting, the investigators said. An early analysis showed that factors influencing the shape of the corneas flexing curve included central corneal thickness, IOP and patient age. The method also allowed the researchers to easily examine keratoconic corneas and corneas after refractive surgery.
The investigators have yet to determine which method produces data on the mechanical properties of the cornea in vivo “that is the most easy to interpret (and is significant) clinically,” the authors said. “Possibilities include wavefront analysis of topographical corneal height data, Fourier decomposition … and flexing-curve analysis.” Tensile strengths of the cornea varies considerably, so “a method to measure elasticity in vivo would help establish narrower clinical safety guidelines for LASIK and other ablative surgical techniques based on individual measurements rather than on trial and error, with a follow-up of several years required,” the study authors said in the January issue of the Journal of Cataract & Refractive Surgery
from osnsupersite posted by Dr.M taherzadeh
Posted by mtaherzadeh at 11:17 PM | Comments (0)
COMBINED INTRAVITREAL INJECTION OF TRIAMCINOLONE ACETONIDE AND PANRETINAL PHOTOCOAGULATION FOR CONCOMITANT DIABETIC MACULAR EDEMA AND PROLIFERATIVE DIABETIC RETINOPATHY
RETINA
Charts of patients undergoing combined IVTA and PRP were reviewed. Outcome measures included visual acuity, presence of macular edema, and response of proliferative disease to laser photocoagulation. All patients maintained stable visual acuity during the treatment period. All patients had improvement in the amount of macular edema, despite the application of PRP, as well as complete regression of their proliferative disease. There were no short-term complications associated with IVTA or PRP.
Posted by kjalali at 07:20 PM | Comments (0)
LONG-TERM EFFECT OF ACETAZOLAMIDE TREATMENT OF PATIENTS WITH UVEITIC CHRONIC CYSTOID MACULAR EDEMA IS LIMITED BY PERSISTING INFLAMMATION
RETINA
To assess the long-term effect of acetazolamide treatment on patients with cystoid macular edema (CME) in the course of intermediate or posterior chronic uveitis and to define those patients who may particularly benefit from the drug, in a study, fifty-two eyes (45 patients) with chronic uveitic CME were treated with acetazolamide at an initial dosage of 500 mg/d. The effect of treatment was assessed by fluorescein angiography, ophthalmoscopy, visual acuity, and Amsler testing. Therapy was withdrawn when CME did not improve at 3 weeks. In cases with CME improvement, the dosage was gradually tapered. Results showed that, low-dose acetazolamide can be a useful therapeutic option for chronic CME in uveitis. The effect is better in patients with quiescence of uveitis than in those with chronically active uveitis. Permanent therapy is not imperative in every case.
Posted by kjalali at 07:13 PM | Comments (0)
EFFICIENT GENE TRANSFER TO RETINAL PIGMENT EPITHELIUM CELLS WITH LONG-TERM EXPRESSION
RETINA
To evaluate the safety and efficiency of feline immunodeficiency virus (FIV) vectors for gene delivery into the mammalian retina, in a study first-generation FIV vector was constructed and administered into rabbit eyes at two different concentrations by intravitreal or subretinal routes. A second-generation FIV vector was also constructed and administered subretinally into both rabbit and rat eyes at the same concentration. After vector administration, eyes were monitored using slit-lamp biomicroscopy, indirect ophthalmoscopy, fundus photography, and electroretinogram, eye tissues were processed for light microscopy and immunohistochemical analysis. The results showed that, second-generation FIV vectors can efficiently transfer genes into RPE cells with resulting long-term expression, properties potentially valuable to gene therapy approaches to some retinal diseases.
Posted by kjalali at 06:55 PM | Comments (0)
FDA UPDATE: Contrast Sensitivity Testing Standards
Worldwide protocols could be adopted this year.As a means to evaluate the quality-of-vision outcomes of today's advanced refractive and IOL implant surgery beyond Snellen visual acuity, the FDA has been requiring companies introducing new technologies to evaluate patient contrast sensitivity during clinical trials.The FDA subcommittee on vision standards evaluated the many types of contrast sensitivity tests, and in 2003 finalized its recommendations for evaluating quality of vision in clinical trials. Of the three types of contrast sensitivity tests, it was determined that contrast sensitivity testing with sine-wave gratings was the most sensitive for this purpose. Letter contrast sensitivity tests (such as Pelli-Robson or Rabin) and low contrast acuity tests (such as 5% or 10% contrast acuity) were rejected as not testing across a wide enough range of visual sensitivity to be appropriate as the primary outcome measure in clinical trials. The FDA also established test protocols, which have been used in FDA clinical trials by every company developing new ophthalmic devices for refractive surgery during the past 3 to 5 years. Each patient is tested using four spatial frequencies of sine-wave gratings, under photopic (85 cd/m2) and mesopic (3 cd/m2) test lighting conditions. In addition to standard mesopic testing, patients are also tested under mesopic conditions with glare.
Posted by mmiraftab at 04:56 PM | Comments (0)