Eyeworld

I THERAPEUTIC REFRACTIVE CORNEAL SURGERY N FOCUS 72 | EYEWORLD | APRIL 2020 Crosslinking alone "The goal of crosslinking is to stabilize the cor- neal biomechanics in order to prevent progres- sion of keratoconus," said Peter Hersh, MD. "It does have the beneficial effect that there is a little bit of decrease in the cone—on average about a diopter and a half—but the goal is to stabilize the cornea." Dr. Rebenitsch said he recommends cross- linking for patients with confirmed keratoconus. "As keratoconus manifests as early as your adolescent years, we are crosslinking earlier and earlier before further damage to the cornea is done," Dr. Rebenitsch said. "Historically, it was thought that keratoconus progression slowed or even stopped later in life. We have good data to show that is not always the case, so we use age as just one factor in evaluating for crosslinking. In general, though, the earlier we can catch it the better." James Loden, MD, offered a similar sen- timent, saying he is a little more aggressive in recommending crosslinking to patients with keratoconus. The current FDA-approved protocol requires documentation of kerato- conus progression and uses an epithelium-off, 30-minute riboflavin soak, followed by 30-min- ute irradiation from a UV-A light using the Avedro (recently acquired by Glaukos) system. Dr. Loden, however, uses a non-FDA approved device, compounded riboflavin, and offers the procedure to patients on a cash-pay basis. "I think the ideal time to treat a patient is when it first shows up in their teens or early 20s. That's where I think the real emphasis needs to be, and I'm coming from the perspective that I have keratoconus. I've been crosslinked," Dr. Loden said, explaining that his procedure was done with the same non-FDA approved system. "I would give anything if we had crosslinking when I was 22 years old because mine pro- gressed to the point where I can see 20/20 with glasses but it's blurry. Gas permeable contact lenses are uncomfortable to wear but they give crisp vision. I wish I had the opportunity to receive crosslinking back then; we could have arrested the disease process in its very early stages." Waiting to show progression, Dr. Loden said, is "dereliction of duty." "It's like saying, we don't want to treat your cancer until you're having a symptom from it," Dr. Loden said, adding that almost all cases of keratoconus will progress. It's just a question of when and how much. Two things that Dr. Rebenitsch said have been "game changers" in decreasing pain and increasing the speed of epithelialization is doing an epi-Bowman keratectomy (EBK) for epithelium removal and using Regener-Eyes in the postoperative period. If an eye was having delayed epithelial healing, Dr. Loden said he would pull steroid drops. "Steroids will impede corneal epithelial healing. The most important thing to prevent a haze reaction, whether it's with PRK, PRK with crosslinking combined, or crosslinking alone, is to get the epithelium healed as quickly as possi- ble. It's not the steroid," Dr. Loden said. Crosslinking and intrastromal ring segments Intrastromal ring segments, often referred to by the brand name Intacs (Addition Technology), are designed to improve corneal contour, mak- ing the cornea less irregular, flattening the cone, and making it more symmetric, Dr. Hersh said. "That's the general goal of using any cor- neal refractive surgery in keratoconus with or without crosslinking," he added. Dr. Hersh said he is a proponent of com- bining the two procedures and referenced a study he coauthored in 2019 that included 200 patients, looking at how crosslinking and Intacs work together and whether the procedures should be performed separately or concurrent- ly. 1 The study found that the combination of crosslinking and intrastromal ring segments leads to "substantial improvement in corne- al topography" and sequential or concurrent procedures "show equivalent outcomes." Dr. Rebenitsch said when he uses Intacs with cross- linking, he performs the procedure concurrent- ly. He counsels patients that there is a chance they will have to be removed in the future but that there may be some residual effect if cross- linking is performed as well. Dr. Hersh said he would recommend Intacs if the patient has poor best-corrected visual acuity, has an inability to wear contact lenses continued from page 71 At a glance • Crosslinking is meant to strengthen a weakened, bulging cornea, stopping progression of keratoconus. It doesn't necessarily improve vision. • Combining crosslinking with therapeutic refractive proce- dures can enhance a patient's ability to wear soft contact lenses, improve visual acuity with glasses, or even improve uncorrected visual acuity. • Therapeutic refractive options include intrastromal ring seg- ments and topography-guided PRK. About the doctors Peter Hersh, MD CLEI Center for Keratoconus The Cornea & Laser Eye Institute Hersh Vision Group Teaneck, New Jersey James Loden, MD Loden Vision Nashville, Tennessee Luke Rebenitsch, MD ClearSight Center Oklahoma City, Oklahoma

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