FEATURE 22 EWAP MARCH 2022 irritation from corneal erosion. “In my practice, this condition is most commonly diagnosed as an incidental finding during a routine eye exam, a refractive or cataract consultation, or those who present for ‘dry eye’ evaluation,” he said. Dr. Houser agreed that EBMD can often present with subtle findings, and patients may not have symptoms. If there are a lot of changes, the cornea looks a little bumpy and irregular on the surface, she said, as well as the tear film. “If you have peaks and valleys in the epithelium where there are a lot of changes, there can be some corneal erosion over the changes, so those patients can present with dry eye symptoms, like watering or burning,” she said. Diagnosing Dr. Thompson noted that this is not always a problem that will be detected before surgery. Often changes in the epithelium can be seen at the slit lamp, but sometimes they can’t. “If a patient has reduced image quality and you do a refraction and can’t make the image clear, do a gas permeable contact lens over refraction, and if it gets clear, we know the surface is the cause,” Dr. Thompson said, adding that epithelial mapping may help with a diagnosis as well. “We can now map the epithelium and prove that it is the issue,” he said. When diagnosing, Dr. Houser said she routinely will use corneal topography and a slit lamp exam. She noted that she doesn’t generally use epithelial mapping but said it can be a valuable technology to help identify EBMD. “Corneal topography can help tell you how much it’s changing the shape of the cornea and in what part of the cornea,” she said. “But I still find that the best way to diagnose this is the slit lamp because you can have irregular topography from so many causes.” Dr. Houser also likes to use corneal dye, but she said that it’s important to only use a little dye, applied with a strip. “I find if I use a combo of fluorescein and numbing drop, I can miss it because there’s so much drop in the eye that it will overwhelm the cornea,” she said. “If I put just a little dye from a strip in, I can see negative staining and find it so much easier.” Dr. Marvasti said you don’t necessarily need any imaging device to diagnose EBMD, and he will often look for the characteristic map, dot, and fingerprint lines. He agreed that these findings will become more apparent with negative staining when a minimal amount of fluorescein dye is used. “I do use imaging modalities, like topography and epithelial mapping, to document the refractive effects of this condition and to assess the effectiveness of treatment,” he said. “For example, I would capture topography before and after epithelial debridement to judge the success of the procedure.” Lastly, Dr. Marvasti said he finds that showing patients an abnormal topography or epithelial map of their eye is an effective way to explain how the condition is affecting their vision. Gas permeable lens over refraction Dr. Thompson said that a soft contact drapes the irregular surface and does not help with the diagnosis, but a gas permeable lens is rigid and maintains its smooth shape. The tear film fills in between the contact and the cornea; then the air/tear interface is smooth because of the contact. “Since there is still refractive error, you put them behind the phoropter and do a ‘better #1 or #2’ manifest refraction, and if it gets crisper than when you refracted them with the contact in place, you know it is corneal surface related,” Dr. Thompson said. Specialty contact lenses have both a therapeutic and a diagnostic role, Dr. Marvasti said. “In my practice, we mainly take advantage of the diagnostic aspect.” A gas permeable lens over refraction can help narrow down the source of limitation in vision and either identify Epithelial map OCT demonstrating central and paracentral epithelial elevations and depressions.
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