Eyeworld

EW CORNEA 130 October 2016 endothelial cells so they don't need any chronic topical steroids," she explained. The procedure adds very little time to the cataract removal. "I did these procedures after cataract surgery while the eye had viscoelas- tic in it from the intraocular lens implantation," Dr. Colby said. "I marked the anterior cornea, put a Sinskey hook in through the cataract wound, and stripped the central Descemet's." For an eye with Fuchs' dystrophy, the new Descemet's stripping without endothelial replacement procedure may help avoid the need for transplantation of foreign cells. With the new technique, diseased cells in the central cornea such as these are replaced by healthier ones with no guttae. Source: Kathryn Colby, MD, PhD Investigators are uncertain why the procedure did not work for everyone. One consideration was whether there may be a different genetic profile of Fuchs' endothe- lial dystrophy in responders versus non-responders. "In this small cohort, we did not see a difference," she said. Likewise, diabetes and smoking, both of which can lead to states of increased oxidative stress, were not correlated with response. However, investigators found that those whose corneas were thicker than 625 microns preoperatively, were less likely to clear, Dr. Colby noted, adding that paradoxically the technique worked in her very first patient who had a corneal thickness of more than 650 microns. What's more, he cleared very quickly. "The good news is if it doesn't work, there are no technical issues with performing subsequent en- dothelial keratoplasty," Dr. Colby said. "Three people in this series did require subsequent DMEK and that was not a problem." In the clinic For patient selection, she encourages practitioners to consider those who have predominantly central guttae with a preserved endothelial mosa- ic in the periphery. "One needs to carefully evaluate the peripheral en- dothelium by slit lamp examination and endothelial imaging," she said. "I would not do this on a patient who has guttae across the entire cor- nea because it's not going to work." Patients who are contemplating De- scemet's stripping without endothe- lial replacement have to understand that the procedure is a novel one that may not work for them, but if it does, it means they will not require someone else's cells in their eyes. "If they're not OK with that, you should go ahead and do your regular phaco DSEK or DMEK," Dr. Colby said. But in cases where it works, patients are usually very enthusiastic. "All of my patients in whom it was successful were very pleased to avoid the need to have a foreign material in their eye and the need for chronic ste- roids," she said. EW Reference 1. Borkar DS, et al. Treatment of Fuchs endothelial dystrophy by Descemet stripping without endothelial keratoplasty. Cornea. 2016;35:1267–1273. Editors' note: Dr. Colby has no finan- cial interests related to this article. Contact information Colby: kcolby@bsd.uchicago.edu After removal of tissue, the cor- nea remains swollen for a period of time before clearing. The time need- ed for this varied between 3 weeks and 6 months. "Most patients who responded to the procedure were clear by 3 months," Dr. Colby said. Dr. Colby theorizes that the rea- son that the patient's cells are often able to cover the defect caused by Descemet's stripping has to do with loss of contact inhibition. "We know that the corneal endothelium is contact inhibited, which means that when the cells reach each other they stop growing," she said. "By phys- ically removing the dysfunctional central endothelial cells, I release the contact inhibition, presumably allowing healthier cells to come from the periphery of the cornea." What remains unknown, however, is whether the cells are just spreading to cover the area, or whether stem cells in the periphery are dividing and sending new cells in once the contact inhibition is released, Dr. Colby said. Finessing continued from page 129

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