Eyeworld

I OCUR SURFACE CONSIDERATIONS FOR SURGERY N FOCUS 34 | EYEWORLD | JUNE/JULY 2020 by Ellen Stodola Editorial Co-Director ters, said Christopher Rapuano, MD. With EK, you're replacing the back layers of the cor- nea. Chronic corneal swelling can cause some epithelial haze or anterior scarring, so a lot of patients who've had edema for a long time can have some scarring. "If it's mild, we usually go ahead with an EK because while mild scarring might decrease vision somewhat, overall, you're better off than with a PK," Dr. Rapuano said. "Sometimes postoperatively when swelling goes away, that scarring may improve over 3–6 months." Even if some of the scarring doesn't go away, it may be treatable with excimer laser PTK. In dealing with severe/deep scarring plus corneal edema, Dr. Rapuano often goes straight to PK. For other surface problems like Salzmann's nodules, epithelial basement membrane dystro- phy (EBMD), or other surface irregularities, it doesn't matter for PK because you're cutting it all out, he said. But for EK, you're removing the back layer, so anything left on the front can still affect vision. Assuming the patient has significant ocular surface irregularities, Dr. Rapuano said there are a couple of ways to handle this. "You can treat it prior to the EK, in the office or with an excimer laser PTK, to try to get the cornea as smooth as possible and then do EK," he said. This would be especially important if doing combined EK and cataract surgery because the A nytime you're going to do a corneal transplant, EK or PK, there are a few important considerations, ac- cording to Deepinder Dhaliwal, MD. One is you have to know whether the cornea is neurotrophic. Some- times the cornea is scarred and hazy, Dr. Dhaliwal said, referencing a case where the patient had an epithelial defect that she initial- ly thought was ruptured bullae. Dr. Dhaliwal performed an urgent transplant but had issues because the eye was inflamed from an ulcer. She tried to do a DMEK but couldn't get the graft to unfold due to a severe fibrinous reaction in the anterior chamber intraoperatively, so she performed DSAEK at a later date. Dr. Dhali- wal stressed the importance of a quiet eye for DMEK. For this particular patient, Dr. Dhaliwal said she didn't check corneal sensation ahead of time. Postoperatively, corneal sensation was reduced. This was when she realized the patient had Fuchs, neurotrophic keratitis, and a re- solved infectious keratitis. The patient had been referred to her as "needing a transplant right away," but Dr. Dhaliwal advised not operating on an actively inflamed eye if it can be avoided. Scarring, defects, and surface abnormalities When deciding between EK and PK, how much anterior corneal scarring there is mat- Ocular considerations prior to keratoplasty At a glance • Superficial keratectomy can help a surgeon address some ocular irregularities prior to keratoplasty. • Preservative-free tears, topical cyclosporine, or lifitegrast can help optimize the surface. Punctal plugs may be used as well. Surgeons also recommend tea tree oil wipes, beaded masks, and artificial tear spray. • OSD, dry eye, and blepharitis may be less of a concern with EK than PK because you're not disturbing the front layers of the cornea. Severe anterior blepharitis Moderate epithelial basement dystrophy with subepithelial fibrosis

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