Eyeworld

EW CORNEA 40 Greenstein et al. performed a multifactorial study that looked at indicators of outcomes and found the only predictor of improvement of corneal topography of 2 D or more was a higher maximum K of 55 D or more. 4 Future of crosslinking Dr. Raizman said epithelium-on (epi- on) treatments should be the goal for this procedure. It's moving in that direction, but at the moment, there's no evidence that epi-on crosslinking is as effective as epi-off, he said. Research continues on vari- ous methods to improve penetration of riboflavin through the epithelium into the stroma—iontophoresis and new riboflavin solutions. Dr. Hersh said epi-on proce- dures, currently considered off-label in the U.S., could be particularly suited for patients whose corneas are too thin for the standard protocol, even with swelling, and those who currently have 20/20 corrected vision. "The reason I say that is there is some risk of loss of corrected vi- sual acuity in crosslinking patients. Whether this is because of corneal haze or epithelial remodeling or just general potential adverse events from a crosslinking procedure, we have shown there may be a slightly greater likelihood of a patient who has good vision losing a line of best corrected vision," he said, adding that the patient thus could be a can- didate for epi-on crosslinking. Another application for the epi- on technique is treating low doses of myopia, hyperopia, and astigma- tism. Photorefractive intrastromal crosslinking (PiXL, Avedro) is cur- rently being researched and received keratectomy, finding the alcohol makes epithelium removal easier. Dr. Kanellopoulos said it's his preference to perform photothera- peutic keratectomy if the epithelium and cornea are regular, but if the epithelium does not show regularity, he uses the Epi-Bowman's Keratec- tomy procedure (Orca Surgical, New York) with the Epi Clear device (Orca Surgical). One also has to take into ac- count corneal scars when consider- ing candidacy for crosslinking. "The first evaluation is, 'Does the patient need transplantation?' … Crosslinking is only going to diminish corneal transplant in those patients who are correctable by glasses or contact lenses. If the cor- neal scar requires a transplant, there is no need to do the crosslinking," Dr. Hersh said, adding that if cross- linking is performed in the face of a scar, perhaps one that is not visually significant, there may be risk for greater incidence of corneal haze. According to Dr. Kanellopoulos, in some cases the scar can be re- moved intraoperatively before cross- linking, which is important as the scar could overshadow the UV light and limit the crosslinking effect in the thinnest, most biomechanically unstable part of the cornea. Following the FDA-approved, on-label Dresden protocol makes patient selection, overall, fairly simple, Dr. Raizman said, but he added that he expects it to become a bit more complex in the future as crosslinking is being considered in combination with other proce- dures, such as PRK or intracorneal ring segments, and in light of newer treatment protocols. Postop care and results The physicians interviewed varied only slightly in their postop care of crosslinking. Dr. Raizman said he'll apply a bandage contact lens and direct the patient to use a fluoroquinolone antibiotic drop four times a day for a week until the epithelium is healed; he'll remove the contact lens at 1 week as well. He also uses prednis- olone acetate 1% four times a day for 1 week and then once a day for a month. He manages pain with oral nonsteroidal and oral narcotics as needed. Similarly, Dr. Hersh uses an anti- biotic/corticosteroid four times a day for a week and a bandage contact lens for 4 to 5 days. He stops the antibiotic at the end of 1 week and tapers the steroid. Dr. Kanellopoulos uses an antibiotic/steroid combination but for 10 days, followed by a steroid drop for at least a month. He advises protection from UV light—sunglass- es and hat wearing—as well as high doses of vitamin C for 2 months. Dr. Greenwood said he uses an antibiotic/steroid combination four times a day for a week, followed by a taper to two times a day for a week. He fits all of his crosslinking patients with dissolvable punctal plugs, finding that they speed healing and prevent haze formation. Although all the physicians in- terviewed said they've seen a strong success rate of crosslinking halting progression in their keratoconus patients, Drs. Swan and Green- wood warned that within the first 6 months after surgery, topographies and vision in these patients can get worse before they get better. A randomized controlled study with 3 years of follow-up saw an average of 2 D of flattening from baseline at 1 year and found this decrease in Kmax was consistent at 3 years with some further im- provement observed between year 2 and 3. 3 In terms of further flattening, Dr. Hersh said research has shown that improved vision is more likely in patients who had worse vision to begin with, 20/40 or more. Crosslinking continued from page 37 " If [crosslinking] is widely recognized and widely available, we can diminish the need for transplants for keratoconus and significantly reduce the number of patients who require contact lens fitting. " —Michael Raizman, MD Like us on Facebook: facebook.com/CorneaSocietyUniversity Find us on social media CORNEA SOCIETY UNIVERSITY (CSU), the newest online educational initiative geared toward cornea fellows and young physicians. June 2017

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