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APRIL 2022 | EYEWORLD | 73 R continued on page 74 W ith keratoconus, it's important to diagnose patients as early as possible in order to treat them before more drastic procedures, like a corneal transplant, might be needed. Crosslinking has aided in the early treatment of keratoconus, and the use of genetic testing is another tool for doctors to add to their armamentarium. Eric Donnenfeld, MD, and Elizabeth Yeu, MD, discussed AvaGen, a test from Avellino that can be used to assess genetic risk for keratoconus and other corneal dystrophies. Genetic testing is one of the newest topics in all of medicine, Dr. Donnenfeld said. Looking at genetic risk factors gives doctors a heads up on better management. Being able to tell if a patient is at risk for a disease allows physicians to diagnose and potentially start therapy earlier. "Keratoconus has been one of the most difficult diseases I've treated in the course of my career," Dr. Donnenfeld said. "Now that we have genetic testing to go along with crosslinking, not only can we diagnose it sooner, but we can treat it sooner and prevent it from progressing." Dr. Yeu finds genetic testing a great tool for keratoconus screening for a variety of patients, such as those in which refractive screenings are not straightforward and family members of known keratoconus patients. She uses this testing in about one of every four refractive screenings. Where does it fit into testing and treatment? Keratoconus is polygenic, meaning there are a lot of genetic variations, so you can't just look at one gene type, Dr. Donnenfeld said. "You have to look at the entire genetic pool and correlate this with other risk factors. Having the genetic testing allows me to know who's at risk to coun- sel them," he said. When someone has keratoconus, family members are at increased risk. Testing siblings and children of keratoconus patients allows them to understand the risks associated with genetic predisposition and how they should be followed. "I find it extremely disconcerting when someone has had keratoconus for several The value of genetic testing for keratoconus years and the first time I see them, they're ready for a corneal transplant," Dr. Donnenfeld said. "I want to diagnose these patients earlier before they get to this stage." Dr. Donnenfeld said he is using genetic testing frequently, but he thinks that it is still being used primarily by corneal specialists at this point. "I think it's something that will be adopted by refractive surgeons who want to have a better understanding of the risks for patients," he said. In addition to genetic testing, Dr. Don- nenfeld uses a number of other tests for these patients. Everyone who comes in gets a topogra- phy and tomography. He looks at posterior cor- nea, corneal thickness, and corneal curvature, and he said that epithelial cell mapping is a new technique that physicians are using as well. Dr. Donnenfeld said he also looks at pachymetry maps. Crosslinking is an effective therapy, he said. "If you know someone is at risk and you follow them carefully and as soon as you see the first sign of development, treat right then, they can lead a normal life," he said. If you don't treat them, they could end up needing corneal transplants, have rejection, and are at risk for trauma. "I think having a test that allows us to di- agnose keratoconus earlier is very exciting," Dr. Donnenfeld said. Though this is not an absolute indication for therapy, it provides more infor- mation to "steer me in the right direction and augments the other tests that I've been doing." Understanding the inherent risk for kera- toconus based on a patient's corneal genetics provides invaluable information, Dr. Yeu said. "I think corneal genetic screening is essen- tial for any refractive screening patients who present with other risk factors on the initial visit, i.e., thinner corneas, young patients with against-the-rule astigmatism, higher astigma- tism, more centrally steep astigmatism. Also, I always screen patients who I'm seeing for an enhancement evaluation for the first time, or in situations where I question the topographic pattern for inferior steepening. Furthermore, I request corneal genetic screening at the initial About the physicians Eric Donnenfeld, MD Ophthalmic Consultants of Long Island Garden City, New York Elizabeth Yeu, MD Virginia Eye Consultants Virginia Beach, Virginia Relevant disclosures Donnenfeld: Avellino Yeu: Avellino by Ellen Stodola Editorial Co-Director

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