EyeWorld India June 2015 Issue

69 EWAP NEWS & OPINION June 2015 Insights from CSCRS: Post-LASIK corneal ectasia and others Among the “Best of CSCRS” presented at a symposium sponsored by the Alliance of Cataract and Refractive Specialty Societies were valuable data from research into ectasia and a new device for pupil expansion C orneal pachymetry and abnormal corneal topographies are closely related to the development of corneal ectasia complications post-LASIK, research has shown. Other variables that surgeons should carefully consider when trying to avoid the infrequent but potentially serious complication after LASIK are surgical optical zones and IOP, said Maria Jose Cosentino, MD , Buenos Aires, Argentina. Dr. Cosentino’s analysis of emerging research on post-LASIK corneal ectasia was given during the Combined Symposium of Cataract & Refractive Societies (CSCRS). The session brought an international field of experts together to review the best presentations from meetings held by the Latin American Society of Cataract & Refractive Surgeons (ALACCSA-R/LASCRS), Asia-Pacific Association of Cataract & Refractive Surgeons (APACRS), and European Society of Cataract & Refractive Surgeons (ESCRS). Reported rates have ranged from 0.02% to 0.06% for post-LASIK corneal ectasia, which manifests as stromal thinning, anterior and posterior corneal steepening, myopia, irregular astigmatism, and decreased distance UCVA and BCVA. Among the inducing factors related to post-LASIK corneal ectasia are corneal thickness of less than 500 microns and a residual stromal bed of less than 300 microns. However, there is no consensus on reliable residual stromal bed thickness for corneal ectasia development. Research results indicate that thin pachymetry is not an isolated risk factor for ectasia in eyes with normal topography. One factor for corneal ectasia is weakened residual stromal beds due to the loss of a large amount of stromal tissue because of high myopia correction. This weakening may stem from the creation of a thicker-than-planned flap or from preop myopia higher than 8 D. On the impact of optical zones, Dr. Cosentino said its diameter modifies corneal ectasia, with the maximum risk occurring at 5 mm. Additionally, intraocular pressure changes are directly proportional to corneal ectasia. Additionally, Dr. Consentino addressed concerns that mitomycin-C might have a role in development of corneal ectasia by noting that she uses it in every LASIK case and has not seen any difference in the rates of corneal ectasia between those patients and her corneal ablation patients. A separate presentation on the different techniques and technologies that surgeons are pursuing in other parts of the world discussed a next generation pupil expansion device. Suven Bhattacharjee, MS, DO , Kolkata, India, discussed his development of a pupil expansion device that would fit with a 20-gauge incision. His device was inspired by difficulties he encountered in fitting the circular scrolls of the Malyugin ring through the incision. “The two-plane design is what catches the incision lip and inserter and makes it difficult,” Dr. Bhattacharjee said about the device previously described in a July 2014 article in the Journal of Cataract & Refractive Surgery. He developed a single-plane square and hexagonal ring—similar to a paper clip—that uses notches or flanges to hook behind the iris and expand it. The Bhattacharjee rings are comprised of 5-0 nylon, which is stiff but flexible and can be com-pressed for insertion before regaining its shape within the eye. Placement can occur through a single 1 mm incision and then the notches can be engaged atraumatically to allow rotation of the ring, which was not possible with previous expansion devices. “Removal has never been so easy; you just need to hold a flange and drag out the device and the trailing notches disengage spontaneously, leaving a wonderful, round pupil,” Dr. Bhattacharjee said. Cases that could benefit from the device include femtosecond laser-assisted small pupil phacoemulsification, shallow anterior chamber procedures, and small pupil vitreous surgery. “The Malyugin ring requires at least a 2.2-mm incision so we really don’t have a device for bimanual co- axial microincision cataract surgery (MICS),” Dr. Bhattacharjee said. In instances where the new device has dropped in the posterior behind the iris it has been easily retrieved, Dr. Bhattacharjee said. Use of the square version of the device is based on personal preference and a desire to reduce the number of surgical steps required because it has one less flange. EWAP Editors’ note: Dr. Cosentino has no related financial interests. Dr. Bhattacharjee has a financial interest in pending patent applications for his device. by Rich Daly EyeWorld Contributing Writer