EyeWorld India June 2020 Issue

EWAP JUNE 2020 37 CORNEA a prior pars plana vitrectomy. Dr. Terry chooses ultrathin DSAEK for complex eyes with previous pars plana vitrectomies, aphakia or anterior chamber IOLs. Choosing DSO DSO involves removing the central 4 mm of Descemet’s membrane. From there the patient’s own cells are used to “rejuvenate” the area, with no graft necessary, explained Deepinder K. Dhaliwal, MD. “We don’t know if the endothelial cells are actually dividing and proliferating or just migrating,” she said, adding that patients are often motivated by this option to avoid a graft. Dr. Terry reserves DSO for Fuchs patients who have VyÕiÌ }ÕÌÌ>Ì> Ìi ViÌÀ> 4–5 mm of cornea. Dr. Dhaliwal recommended only selecting patients who have functional vision in their fellow eye, citing prolonged visual recovery, even in rapid responders. Visual recovery can take 3–4 weeks. “The person has to be well educated [on the procedure] and very patient,” she said, explaining that vision on the wÀÃÌ `>Þ «ÃÌ -" Ã i > “whiteout” from corneal edema. She also requires that patients have a peripheral endothelial cell count of more than 1,000 mm 2 . In a study, Dr. Dhaliwal and co-investigators found that 20/40 vision was attained 7.2 weeks after DSO vs. 2.2 weeks for DMEK. 2 ÜiÛiÀ] > LiiwÌ of DSO is avoiding the graft and immunosuppression. Dr. Dhaliwal does recommend using a rho kinase inhibitor 4 times a day for 6–8 weeks to help stimulate the peripheral endothelium. In DSO cases where the cornea does not clear after 6 weeks, Dr. Terry performs a “rescue” DMEK procedure to avoid corneal haze. Dr. Terry views this as a transformative time for endothelial transplant procedures. “The advances in treating endothelial failure have never been more exciting than they are right now,” he concluded. EWAP References 1. Kurji KH, et al. Comparison of visual acuity outcomes between nanothin Descemet stripping automated endothelial keratoplasty and Descemet membrane endothelial keratoplasty. Cornea . 2018;37:1226–1231. 2. Huang MJ, et al. Descemetorhexis without endothelial keratoplasty versus DMEK for treatment of Fuchs endothelial corneal dystrophy. Cornea . 2018;37:1479–1483. Editors’ note: Dr. Dhaliwal is professor of ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, and declared relevant interests with CorneaGen and Trefoil. Dr. Holland is professor of ophthalmology, University of Cincinnati, Cincinnati, Ohio, and declared relevant interests with CorneaGen and Minnesota Lions Eye Bank. Dr. Terry is director of Corneal Services, Devers Eye Institute, Portland, Oregon, and declared no relevant ƂPCPEKCN KPVGTGUVU Donald Tan, MD Professor, Singapore National Eye Centre 11 Third Hospital Ave., Singapore 168751 ASIA-PACIFIC PERSPECTIVES T he article “Endothelial transplants on the cutting edge” by Dhaliwal, Holland, and Terry, offer an excellent overview on the state-of-the-art changes in the way we treat endothelial dysfunction. While EK is now the predominant form of keratoplasty in North America and Europe, penetrating keratoplasty (PK) still remains the dominant procedure in many developing countries, especially in Asia. EK is dominant in only a few developed Asian countries such as Japan and Singapore. The reasons for the lower adoption rates of EK in many Asian countries include limited access to eye bank-prepared, pre-cut DSAEK tissue, limitations in training of surgeons, and also more severe corneal morbidities—late stage presentations with Ã}wV>Ì VÀi> ÃV>ÀÀ} «ÀiVÕ`i }` ÛÃÕ> ÕÌViÃ >` >i Ài `vwVÕÌ Ì «iÀvÀ] iÃ«iV>Þ ° In the West, Fuchs dystrophy, mostly presenting early, remains the main indication for corneal transplantation, whereas in Asia, pseudophakic bullous keratopathy (PBK) is more common. PBK has been shown to have higher rejection and graft failure rates as compared to Fuchs dystrophy simply because the latter tends to present with milder disease severity, and fewer comorbidites. Despite this, data from the Singapore Corneal Transplant registry (SCTR), the only long-term Asian corneal transplant database, clearly show that EK in Asian eyes still offers greater advantages in terms of better graft survival rates, less rejection, and less glaucoma. A recent SCTR publication comparing PK with DSAEK and DMEK revealed 5-year graft survival rates of 54.6%, 78.4%, and 97.4% respectively. 1 Moreover, Fuchs cases in this study showed much enhanced graft survival rates (73.5%, 96.2%, 98.7%) as compared to bullous keratopathy which had 5-year survival rates of 47%, 65%, and 95% for these three procedures. These results were largely related to major differences in rejection rates of 14%, 5%, and 1.7% for PK, DSAEK, and DMEK. In Asia, DMEK is now also slowly emerging as an increasingly important form of EK mainly due to the fact that pre-cutting of DSAEK tissue is no longer needed. However, new skillsets for DMEK remain important in Asia to handle the increased severity of disease, and enhanced surgical challenges in performing this more complex procedure in PBK cases with comorbidities such as glaucoma, glaucoma drainage devices, iris abnormalities, and unstable implants. Leading corneal surgeons in Asia are now challenging the paradigm on how to perform DMEK in these more complex cases, and as we continue to adopt DMEK and DSAEK in Asia, our graft success rates will continue to improve, for the betterment of our corneal patients. Reference 1. Woo et al. DMEK versus DSAEK and PK. Am J Ophthalmol. e-pub: https://doi.org/10.1016/j.ajo.2019.06.012. Editors’ note: Dr. Tan is a consultant for Santen and Eye-Lens and receives Royalty Support from Network Medical UK for an EK inserter device.