Eyeworld

JAN 2019

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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EW FEATURE 46 Crosslinking playbook • January 2019 by Vanessa Caceres EyeWorld Contributing Writer AT A GLANCE • Epithelium-off CXL is currently approved in the U.S. Some surgeons are performing epi-on CXL in U.S. clinical trials. • Surgeons should counsel CXL patients to not rub their eyes. • Pain management can include oral analgesics, lubricant eye drops, an antibiotic, and an anti-inflammatory agent. Surgeons generally advise waiting about a month before a patient gets new glasses or contact lenses. • Patients should be monitored about every 3 months the first year after CXL. Progression may be more common in younger patients. upon patients the importance of not rubbing the eyes." Dr. Majmudar does not usually counsel patients to avoid sleeping on their face or side, but he said this advice could be use- ful in severe cases, as it may cause undue pressure on the cornea. Postop pain control When helping patients control pain after CXL, Dr. Talley Rostov prescribes four tablets of hydroco- done acetaminophen and one tablet of lorazepam. Patients are also prescribed topical Prolensa (brom- fenac ophthalmic solution, Bausch + Lomb, Bridgewater, New Jersey) four times daily for 3 days, topical Lotemax (loteprednol etabonate gel, Bausch + Lomb) or Pred Forte (pred- nisolone acetate, Allergan, Dublin, Ireland) four times daily for a week and a tapering dose. Polytrim (poly- myxin B/trimethoprim ophthalmic solution, Allergan) antibiotic drops are used until the epithelium is healed. Preservative-free artificial tears are also part of the mix. Pa- tients can begin using their contact lenses 2 weeks after the procedure, Dr. Talley Rostov said. Another consideration is the patient's updated refraction. "Most patients are advised to wait for 1 month prior to getting a new pre- scription for eyeglasses or contact lenses in the event that there is some remodeling of the cornea that can be taken into consideration in the first 4–6 weeks," Dr. Majmudar said. Decentering the CXL light source William Trattler, MD, Center for Excellence in Eyecare, Miami, said research from Michael Mrochen, PhD, Zurich, Switzerland, presented in recent years showed the impor- tance of rotating the eye so that UV light is centered on the thinnest or weakest area of the cornea. "For pellucid marginal degeneration, where the cornea is thin inferiorly, the patient is asked to look above the light, and the center of the light is decentered inferiorly," Dr. Trattler said. More recently, Theo Seiler, MD, published results demonstrat- ing that customized crosslinking provides greater flattening and reshaping compared to standard CXL. 1 Dr. Majmudar does not decenter the light source over the cone as his current protocol uses a 12 mm beam that encompasses the entire cornea. Eye rubbing The message is clear: Tell patients to avoid eye rubbing. "We recommend that all patients stop eye rubbing, as this ap- pears to be an important risk factor for keratoconus," Dr. Trattler said. "Not all patients with progressive keratoconus rub their eyes, but for those who do, we discuss the impor- tance of avoiding eye rubbing." "I think that some cases of post-CXL progression may be due to continued eye rubbing," Dr. Majmudar said. "We try to impress obtain non-Food and Drug Admin- istration-approved devices from overseas and try to perform epithe- lium-on crosslinking with those de- vices, which have not been evaluat- ed for epithelium-on crosslinking," he said. "It is not possible to use technology that has not specifically been designed for epi-on CXL and expect the same level of efficacy as we are getting with currently ap- proved epi-off or proprietary epi-on devices." Riboflavin and light sources The doctors interviewed by EyeWorld get their riboflavin from their trial sponsors, be it Avedro, as Audrey Talley Rostov, MD, Northwest Eyes, Seattle, does, or CXL USA. "I use it according to their standard proto- col, 30-minute soak with 3-minute light time," Dr. Talley Rostov said. Dr. Majmudar shared his expe- rience. "Currently in the CXL USA trial, we are varying the fluence and duration of UV exposure between 20 and 30 minutes," he said. This is not considered accelerated CXL, which is typically described as a UV exposure of only 3 to 5 minutes, he added. Determining corneal thickness intraop Corneal thickness measurements during the procedure can help decide whether surgeons should use hypotonic riboflavin or if they should thicken up the cornea. "I measure before applying UV light with a PachPen handheld pachymeter [Accutome, Malvern, Pennsylvania]," Dr. Talley Rostov said. "I usually use standard ribofla- vin, but with a thin cornea or if I'm leaving the speculum in during ri- boflavin drops, I will alternate with standard and hypotonic riboflavin," she explained. Although the original CXL trials in Europe used 400 microns as the "magic" number to initiate UV light treatment, Dr. Majmudar said, corneal thickness is less vital with epi-on technology. "Our current clinical protocol requires us to have the thinnest portion of the cornea above 375 microns. In the vast ma- jority of cases that we treat, this is easily attained, especially if we start to treat patients at earlier stages of keratoconus," he said. Surgeons share pearls for better CXL outcomes A s U.S. surgeons increase their use of corneal cross- linking (CXL) to treat keratoconus, better intra- operative and postoper- ative approaches can help improve outcomes. EyeWorld asked some seasoned CXL users for their intraop and postop insights. Is epi-on an option? For now, only the epithelium-off system from Avedro (Waltham, Mas- sachusetts) is approved in the U.S. However, Avedro is doing an epi-on CXL clinical trial, and surgeons are eager to see the results, said Parag Majmudar, MD, president and chief medical officer, Chicago Cornea Consultants, Chicago. In addition, the CXL USA study group (Bethesda, Maryland) has done epi-on treat- ments since 2010. "That group is currently evaluating a proprietary epithelium-on system, and the clin- ical results have been outstanding," Dr. Majmudar said. He has per- formed epi-on treatments with CXL USA since 2010. Because epi-on treatments ap- pear so promising, Dr. Majmudar is concerned about surgeons who want to perform epi-on CXL, especially in the pediatric population, and may use the current epi-off technology in an epi-on fashion. "Or even more concerning, some surgeons may CXL playbook for intraop and postop management An in-treatment image of a patient undergoing corneal crosslinking using the FDA-approved Avedro protocol Source: J. Bradley Randleman, MD

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