Posts Tagged ‘Keratoconus’

Dr. Raymond Stein Speaks at ASCRS

Thursday, April 7th, 2011

Dr. Raymond Stein was an invited guest speaker to the annual meeting of the American Society of Cataract and Refractive Surgery (ASCRS) in San Diego on March 28, 2011. He presented the results from the Bochner Eye Institute of Corneal Collagen Crosslinking with up to 3.5 years of follow-up. None of the treated patients have shown any progressive ectasia. Crosslinking has been shown to be a major advance in the treatment of keratoconus, pellucid marginal degeneration, and ectasia after refractive surgery. The surgeons at the Bochner Eye Institute have been pioneers with this technology in North America. To learn more about Raymond Stein, MD, & Bochner Eye Institute, please call (416) 960-2020.

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Phakic Implants for High Refractive Errors

Friday, January 21st, 2011

Dr Raymond Stein of the Bochner Eye Institute wrote the following clinical update. We hope you find it of interest.

Phakic implants are used in vision correction for high refractive errors that cannot be treated by laser vision correction. Over the past 13 years we have been inserting the Implantable Contact Lens (ICL), a posterior chamber phakic implant made by Starr Surgical. Clinical outcomes for high myopia and astigmatism have generally been excellent with 95% of eyes achieving 20/30 or better uncorrected vision. The main indications are refractive errors that are too high for laser vision correction. In general patients are candidates for a phakic implant if they have myopia greater than 10 D or hyperopia greater than 5 D. Astigmatism can be treated up to 6 D. Patients must have a satisfactory depth of the anterior chamber (distance between the corneal endothelium and the crystalline lens) of greater or equal to 2.8 mm. Most of the high myopes will qualify unlike the high hyperopes. Patients should also have a pupil size of 7 mm or less.

Another surgical option, which patients need to know about in the informed consent, is a refractive lens exchange. Our preference is not to perform a lens exchange for high myopia because of the increased risk of retinal tears and detachment. This is not the case with the treatment of high hyperopia, which is associated with a minimal retinal risk.

In patients that are good candidates for the ICL, a refraction is performed, the limbal white-to-white distance is measured to determine the length of the implant, and two small YAG laser iridotomies are performed to reduce the risk of elevated intraocular pressure from papillary block. The implant is custom ordered from Switzerland.

The surgical procedure is relatively easy for patients. At the Bochner Eye Institute we perform this procedure in our sterile operating room approved by the Ontario College of Physicians and Surgeons. Under topical anesthesia a 2.8 mm limbal incision is constructed. Intraocular xylcaine is injected to numb the contents of the eye. After the implant has been carefully folded into a cartridge it is injected into the anterior chamber where it gradually unfolds. Using a specialized instrument the haptics are gently placed behind the iris. Miochol is then injected to constrict the pupil. Intraocular Vancomycin is injected to prevent infection. The patient is then checked one hour postoperatively to be sure the intraocular pressure is normal. Follow-up examinations are usually 1 day, 1 week, 1 month, and 3 months.

Complications are rare. The main risk is inducing a cataract (1%). If patients are not satisfied with their level of uncorrected vision then laser vision correction can be performed. We have not had a case of infection over the past 13 years.

Specialized indications for the ICL include patients with keratoconus and those following radial keratotomy. In keratoconus patients if they have satisfactory best-corrected spectacle acuity (20/40 or better) then consideration can be given to the ICL. Patients may require an Intracorneal ring to reduce the degree of irregular astigmatism prior to a phakic implant. In the situation following radial keratotomy if patients have developed a hyperopic shift then this can be corrected by the ICL. Unlike a natural hyperope the post-RK eyes were previously myopic and usually have a satisfactory anterior chamber depth.

Update on Corneal Collagen Crosslinking (CXL) for Keratoconus

Friday, July 17th, 2009

At the Bochner Eye Institute we were the first in North America to introduce CXL using Riboflavin drops and epithelial removal in January 2008. Over the past 1.5 years we have treated 495 keratoconus eyes with encouraging clinical results.

The main goal of CXL is to halt the progression of keratoconus and thus prevent the need for a corneal transplant.. At the Bochner Institute patients have ranged from 11 to 60 years of age. The earlier the treatment the better the long-term prognosis. We have not seen a case of progressive ectasia post-CXL. Our minimum corneal thickness has been reduced from 400 um to 300 um with the technique of inducing corneal swelling prior to crosslinking.

Dr Raymond Stein was invited to present clinical results at the annual Canadian Ophthalmological Society meeting in Toronto June 2009. The 12 month results of 30 eyes were reported that were followed with a refraction, pachymetry, and Pentacam analysis. Some patients achieved up to 8 diopters of flattening. Topographic difference maps often showed flattening of steep areas and steepening of flat areas to enhance the overall corneal curvature and improve best-corrected spectacle acuity. Sixty percent of eyes showed improvement of one or more lines of vision.

As in Europe which started CXL 11 years ago the procedure is now being rapidly adopted as the preferred treatment for keratoconus eyes with progressive disease. At the Bochner Eye Institute we are continuing to have patients referred from ophthalmologists and optometrist from as far away as Miami, Dallas, and Los Angeles.

If you would like further information on CXL or an opportunity to view a procedure please contact one of our refractive surgery consultants Ms Kristin Mallon (KMallon@Bochner.com), Mr Peter Schilling (PSchilling@Bochner.com, or Ms Lynn Maund (LMaund@Bochner.com).

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