Eyeworld

66 | EYEWORLD | APRIL 2020 R EFRACTIVE W hile surgeons might have tradi- tionally performed a full-thick- ness corneal transplant on a patient with a history of radial keratotomy (RK) scars and corneal decompensation, Jim- my Lee, MD, described success with an endothelial transplant. 1 A 56-year-old patient with a prior 16-cut RK had corneal edema from Fuchs corneal dystrophy with a thickness of 571 µm, cataract, and vision of 20/400 in the affected eye. She was treated for the cataract first. "The idea was to take care of the cataract alone and see how much the vision improved with the least invasive approach," Dr. Lee said. The patient's vision improved to 20/70 with cataract surgery and intraocular lens implantation, but after about 4 months, her vision deteriorated to 20/200 and her corneal thickness increased to more than 700 µm. "The cataract surgery probably caused the rest of the functioning endothelium to decom- pensate," Dr. Lee said. At this point, the patient's corneal edema had to be addressed. They had to decide wheth- er to do a full-thickness corneal transplant or replace the corneal endothelium alone, Dr. Lee said. A full-thickness corneal transplant would have been justifiable because of the patient's anterior RK scars and posterior endothelial dys- function. "However, we decided to pursue the latter as endothelial replacement alone offers faster recovery and less astigmatism," Dr. Lee said. While DMEK is more challenging than other types of endothelial keratoplasty, Dr. Lee explained that it has the advantage of better postoperative visual acuity. By replacing tissue for tissue (DMEK grafts) without additional stromal tissue (DSAEK grafts), there is less light scattering and less risk for interface haze. "Her vision improved to 20/40, and the donor Descemet's membrane cleared the edema completely," Dr. Lee said. The surgery itself was routine, with no issues due to the previous RK. "There's quite a bit of corneal manipulation during the DMEK procedure to unscroll and manipulate the donor Descemet's membrane graft to the proper orientation," he said. "The concern was that the RK scars would splay open." Dr. Lee theorized that this didn't happen because the patient's RK procedure was performed decades ago and the incisions were likely scarred. There was also concern about intraoper- ative visualization being affected by the RK scars. "The other issue is that sometimes the RK scars are relatively central, deep, and long, and this can obscure the view into the anterior chamber," Dr. Lee said. Fortunately, this wasn't an issue. When deciding whether or not to undertake a DMEK procedure, it comes down to the sur- geon's experience and comfort with the tech- nique, Dr. Lee stressed. For those comfortable with DMEK, it could be the preferred choice. However, an RK patient might not be the best first case for DMEK. "If you don't have any experience with DMEK surgery, DSAEK is certainly a viable option for patients who have had prior RK," Dr. Lee said. "But if you have experience with DSAEK and DMEK, DMEK is a good first-line option for these patients." Performing DMEK on prior radial keratotomy patients Postoperative slit lamp photo of the cornea with clear DMEK graft in the setting of RK scars Source: Jimmy Lee, MD Contact Lee: lee.jimmy.k@gmail.com by Maxine Lipner Senior Contributing Writer About the doctor Jimmy Lee, MD Associate professor of ophthalmology and visual sciences Montefiore Medical Center Albert Einstein College of Medicine New York, New York Reference 1. Akella SS, et al. Descemet membrane endothelial kerato- plasty for endothelial decom- pensation after previous radial keratotomy. Am J Ophthalmol Case Rep. 2019;15:100503. Relevant disclosures Lee: None RESEARCH HIGHLIGHT

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