Eyeworld

60 | EYEWORLD | DECEMBER 2021 R EFRACTIVE Contact Houser: kourtney.houser@gmail.com Marvasti: amarvastimd@gmail.com Thompson: vance.thompson@ vancethompsonvision.com Relevant disclosures Houser: None Marvasti: None Thompson: Alcon, Bausch + Lomb, Carl Zeiss Meditec, Johnson & Johnson 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 con- tact. "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 thera- peutic 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 vi- sion and either identify or rule out the cornea as the main site of pathology, he said. For example, in a patient with irregular astigmatism (ectasia, corneal scar, Salzmann's nodule, etc.) and other ocular pathology (cataract, macular degener- ation, etc.), he said a gas permeable lens over refraction will identify what the vision potential would be if the corneal shape and astigmatism were regular. "This will help us in counseling the patient and recommending the best next treatment modality," Dr. Marvasti said. Dr. Houser said she wants to know the po- tential of the patient's eye, whether that patient is having cataract surgery or not. "Gas perme- able or scleral lenses over refraction are useful to determine what the eye can see beyond the irregular cornea," she said. "Whether the corne- al changes are from EBMD or another disease, you can put a hard contact lens on, do refrac- tion, and know what the potential of the eye is if you could fix the cornea and tear film." Dr. Houser uses this before cataract surgery because it helps tell her how much of the vision change is due to the cornea. Healing time and waiting before surgery Dr. Houser said she likes to wait about 6 weeks after treating EBMD before proceeding with cat- aract surgery. Treatment like superficial keratec- tomy may be used in these cases. "I tell patients 4–6 weeks, but usually I like to wait 6 weeks for the cornea to fully remod- el," she said, adding that some physicians may choose to wait 2–3 months. She also alerts patients that if they still have irregularity on topography, the wait may be longer. Dr. Houser added that this is also a con- dition that can recur, though she said patients usually don't need retreatment for some time. "It's rare that I have to do retreatments within several years," she said. Dr. Thompson added that after doing epithelial scraping or PTK, it can take about 3 months for best vision to be restored. Dr. Marvasti said for a patient with EBMD with multiple recurrences of corneal erosion or those with the dystrophy affecting the visual axis, he will typically recommend epithelial de- bridement with diamond burr polishing. "This treatment has worked the best for my patients, especially after failing other more conservative options," he said. "The healing time can range from weeks to 1–2 months." Generally, Dr. Marvasti said he starts with more conservative treatment options, which can include ocular surface optimization with ocular lubricants, nighttime lubricating ointments, serum tears, amniotic membrane, hypertonic sa- line solution or ointment, bandage contact lens, and topical antibiotics for corneal erosions. Surgical options, he said, include epitheli- al debridement with or without diamond burr polishing, PTK, and stromal micro-puncture. He again stressed that he typically uses epithelial debridement with diamond burr polishing for someone who has failed with more conservative options. Dr. Marvasti noted that recurrence after sur- gical intervention is low, adding that he has not personally seen someone with recurrent corneal erosions after a thorough epithelial debride- ment with diamond burr polishing. "The main point is always having a high degree of suspicion for EBMD in someone with fluctuation in vision, monocular diplopia, or anyone seeking to have cataract or refrac- tive surgery," Dr. Marvasti said. "As one of my mentors told me, 'You'll miss it if you don't look for it.'" continued from page 59

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