CORNEA 36 EWAP MARCH 2023 Giegengack explained, so when we strip away portions of Descemet’s membrane, the remaining endothelial cells will grow and “morph” to fill in the gaps. Dr. Giegengack uses this procedure and thinks it works well for a small subset of Fuchs patients with focal central guttata and corresponding corneal edema that doesn’t extend out to the periphery of the cornea. “You can remove that central area of guttata and treat with ROCK inhibitor drops,” he said. “Peripheral endothelial cells can expand back into the center and fill in the gap. The advantage of this approach is that patients have the potential to regain vision without the risk of transplant rejection.” However, he noted that DSO can take a long time to heal, and sometimes patients’ vision isn’t improved, and they do need to undergo a corneal transplant. He added that he’s picky about when he performs DSO. Dr. Holland also explained that corneal endothelial cells do not naturally regenerate in vivo, and if cells die, the remaining cells will expand and enlarge to form tight junctions with remaining endothelial cells. “Thus, by stripping Descemet’s membrane in the cornea’s central area, the remaining endothelial cells at the periphery will likely enlarge and gravitate to the center,” he said. “However, in some cases, enlarged corneal endothelial cells may cease to maintain their pump and barrier functions, thereby increasing corneal edema and potentially resulting in hazy vision in the long term.” He added that this procedure is limited to those corneas with a small area of central guttata, and there can be a long recovery period. Dr. Berdahl said it’s unknown exactly how cell redistribution works with DSO. It is likely at least partially driven by contact inhibition. Endothelial cells stop growing when they touch other endothelial cells, and by removing an area of endothelial cells, the endothelial cells migrate to cover the cells that have been removed because there is no longer an adjacent contact. Dr. Berdahl said that he has not used DSO in clinical practice and thinks the majority of endothelial dysfunction treated surgically is with DMEK or DSAEK, with the exception of some cases where only central guttata are present. Dr. Yeu also noted that patients have a longer recovery with DSO; it could take up to 8 weeks for vision to recover with a lot of corneal swelling in the interim. However, she does see its potential in the future because it doesn’t have the allograft rejection. “If we could do DSO with a ROCK inhibitor, there may be patients who would consider that versus scraping and cells,” she said. Moving forward Dr. Giegengack stressed the potential for cell therapy, not just in the U.S. but also internationally. Noting that he’s done humanitarian work in developing countries, Dr. Giegengack said that corneal transplants tend to have lower success rates there than in the U.S. “I think cell therapy has the potential to decrease that discrepancy,” he said. “Because cell therapy is a less complex procedure, I think it will potentially require less follow-up and have fewer complications. [These are] especially important benefits for patients in underserved parts of the world.” Dr. Yeu mentioned the possibility of having the option to cryopreserve. This isn’t a foreign idea, she said, noting that it’s used for amniotic membranes. She said it would “change the way we think” to be able to use these cells and defrost them when you need them. She added that it’s been promising to see patients in studies so far who had significant visual issues, vision worse than 20/40 and up to 20/800, some with worse than 600-micron corneas. “To see these types of cornea patients at the level they’re at is very promising,” Dr. Yeu said. “It is heartening to know that corneal endothelial dystrophies are now the focus of multiple avenues of research and development,” Dr. Holland said. “I think these innovations will yield safe and efficacious options for patients suffering from corneal endothelial diseases. For example, I think that cell therapy might be used across the entire disease spectrum, which would potentially mean the ability for us to treat patients earlier in the course of their disease. I do think endothelial cell therapy will become the treatment of choice for the majority of patients with endothelial disease.” EWAP References 1. Kinoshita S, et al. Injection of cultured cells with a ROCK inhibitor for bullous keratopathy. N Engl J Med. 2018;378:995–1003. 2. Numa K, et al. Five-year follow-up of first 11 patients undergoing injection of cultured corneal endothelial cells for corneal endothelial failure. Ophthalmology. 2021;128:504–514. Editors’ note: Dr. Berdahl practices at Vance Thompson Vision, Sioux Falls, South Dakota. Dr. Giegengack is Associate Professor of Ophthalmology, Wake Forest University School of Medicine, Greensboro, North Carolina. Dr. Holland is Professor of Ophthalmology, University of Cincinnati, Cincinnati, Ohio. Dr. Yeu is in practice with Virginia Eye Consultants, Norfolk, Virginia. All the doctors have interests with Aurion Biotech.
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