Eyeworld

EW ASCRS PREVIEW 38 March 2011 by Enette Ngoei EyeWorld Contributing Editor The impact of clear corneal incisions Eric D. Donnenfeld, M.D., will present a study quantifying the effect of clear corneal incisions on the ocular surface A ttendees of the 2011 ASCRS Symposium and Congress can expect sev- eral presentations on first- time studies of clinical importance. One of these is on the effect of cataract surgery and limbal relaxing incisions (LRIs) on the corneal surface. Eric D. Donnenfeld, M.D., co- chairman, cornea, Nassau University Medical Center, East Meadow, N.Y., explained how dry eye and corneal sensation have become important considerations in all patients having cataract and refractive surgery, and there is a new appreciation for the importance of the ocular surface on quality of vision following all sur- gery. There's been a tremendous amount written about the role of LASIK and PRK on corneal sensation, but no one has looked at LRIs and the effect of these corneal incisions on the ocular surface associated with cataract surgery, he added. "Our anecdotal experience has been that patients who have LRIs do have staining adjacent to the LRIs and the apparent loss of corneal sen- sation, but this has never been quantified previously in any useful study," Dr. Donnenfeld said. Dr. Donnenfeld and colleagues conducted a prospective, multicen- ter, observational trial, enrolling pa- tients scheduled for cataract surgery with intraocular lens placement and LRIs to correct corneal astigmatism. "We took 40 patients undergo- ing cataract surgery with LRIs and we looked at the change in corneal staining and corneal sensation cen- trally and adjacent to the LRIs and 90 degrees away from the LRIs," he said. Patients received open-label gat- ifloxacin 0.3%, ketorolac 0.45%, and prednisolone acetate 1% for 4 weeks and Refresh tears (Allergan, Irvine, Calif.) as needed for up to 3 months. The primary efficacy measure was corneal sensation (Cochet-Bonnet esthesiometer); secondary measures included tear break-up time, corneal staining, Schirmer's testing, and fre- quency of artificial tear use. Dr. Donnenfeld said that the re- sults of the study were consistent with anecdotal evidence. "We did find that there was a significant loss of corneal sensation adjacent to the LRIs; there was in- creased corneal staining in these re- gions as well," he said. The study that will be presented at ASCRS will show the impact of clear corneal incisions on corneal sensation and the importance of op- timizing the ocular surface in pa- tients having LRIs, which are becoming increasingly common. Dr. Donnenfeld said, "We be- lieve limbal relaxing incisions are ef- fective therapies for pre-existing cylinder; however, attention to the ocular surface should be paid in these patients to make certain pa- tients have optimal results." To optimize the ocular surface, he said, "In general, we believe that all patients having any type of sur- gery should have an evaluation of the ocular surface starting by look- ing at the meibomian glands and the tear film and by doing supravital staining with lissamine green and rose bengal to look for signs of dry eye or meibomian gland dysfunc- tion; then the practitioner should evaluate tear break-up time and corneal staining with fluorescein." Any patient who has pre-exist- ing disease or any type of dry eye should expect that the dry eye will be made worse by the surgery, and for this reason, pre-existing dry eye should be aggressively treated before any type of surgery, Dr. Donnenfeld stressed. While there will always be loss of corneal sensation, there is some new evidence that cyclosporine may reduce the long-term loss of corneal sensation associated with corneal surgery, he said. But even if there is a loss of corneal sensation, this can be overcome by optimizing the tear film and improving the quality of the tear film, he added. "If you can improve the quality of the tear film, patients will tolerate the mild loss of corneal sensation and do well. The loss of corneal sen- sation is also more significant imme- diately following surgery and tends to improve over time as the cornea heals," Dr. Donnenfeld said. EW Editors' note: Dr. Donnenfeld is a con- sultant for Abbott Medical Optics (Santa Ana, Calif.), Alcon (Fort Worth, Texas), and Bausch & Lomb (Rochester, N.Y.). Contact information Donnenfeld: 516-766-2519, eddoph@aol.com San Diego, March 25-29, 2011 Eye with a limbal relaxing incision to correct astigmatism Source: Samuel Masket, M.D. Eric D. Donnenfeld, M.D.

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