Eyeworld

EW FEATURE 78 by Maxine Lipner EyeWorld Senior Contributing Writer AT A GLANCE • A Scheimpflug-style mapping device can help practitioners track which keratoconus patients are progressing, need crosslinking, and responding effectively to treatment. • A busy practice may wish to schedule crosslinking procedures on certain days and/or intersperse these with office patients. • Insurance doesn't yet cover crosslinking, but the hope is that it eventually will and that it will be adequate enough to compensate for sizable costs. thickness is 400 microns or thicker prior to initiating the UV light. If the corneal thickness is less than 400 microns after loading, then one can initiate hypotonic riboflavin to thicken the cornea to 400 microns. "Besides making sure that the thick- ness is at 400 microns, after loading the cornea with riboflavin, physi- cians need to examine the cornea at the slit lamp to verify there is enough riboflavin in the cornea to proceed with the UV light applica- tion," Dr. Trattler said. "It's import- ant to check because if there's not enough riboflavin, the cornea will receive inadequate treatment." Logistics It's also important to decide the logistics of who will be administer- ing the crosslinking treatment. This will depend on how the practitioner is going to set it up, according to Francis Price Jr., MD, founder, Price Vision Group, Indianapolis, and president of the board, Cornea Research Foundation of America. "As long as you're doing epi-off, the physician will probably be the one to take the epithelium off," Dr. Price the changes in their corneal shape every 3 to 4 months. With tomogra- phy or topography, difference maps that show the pre-treatment map and most recent map, along with the changes, allow the clinician to more carefully track the changes in the corneal shape over time, he said. To stay on-label, physicians need the KXL System (Avedro, Waltham, Massachusetts). This de- vice is FDA approved for progressive keratoconus as well as most recently for post-LASIK ectasia, Dr. Trattler noted. Post-LASIK ectasia by itself is progressive by definition. "You don't have to prove progressiveness if you want to stay on-label with ectasia, but you do with keratoconus," he said. The riboflavin drops, Photrexa and Photrexa Viscous (Avedro), are required to turn on the UV light source. There is a chip or card with the packaging of the drops that enables practitioners to activate the light source for one use, Dr. Trattler explained. One of the criteria for initiating the UV light is to ensure that after the riboflavin loading, the corneal the disease becomes more advanced, the technology can not effectively image the cornea. "While topog- raphy will provide some informa- tion in advanced keratoconus, you will not typically be able to track the outcomes of crosslinking," he said. "It will help to acquire more advanced corneal imaging technol- ogies to get involved in crosslink- ing. Physicians will want to get a Scheimpflug-style mapping device, either the Pentacam [Oculus, Wet- zlar, Germany] or the Galilei [Ziemer Ophthalmic Systems, Port, Switzer- land]." Such technology is often called corneal tomography. Physicians need this technology first to track keratoconus patients and determine if they're progressive and then, after crosslinking, to make sure they're stable or improving, Dr. Trattler explained. "When patients with progressive keratoconus under- go epi-off crosslinking, the risk for progression is about 3%," he said. "While 97% of eyes require just one crosslinking procedure, 3% of eyes will benefit from a second procedure." Postoperatively, it's im- portant to follow patients and track Incorporating this newly approved procedure into a practice U ntil now, treatment of keratoconus or ectasia with crosslinking has been confined to studies or to off-label use. Now that the FDA has officially given the cross- linking procedure the nod, many practitioners are thinking about in- corporating this into their practices. There's a high level of interest, according to William Trattler, MD, Center for Excellence in Eye Care, Miami. "I think that every doctor comes across patients throughout the year who have keratoconus, and there are probably more patients with keratoconus than physicians realize," he said, adding that if you focus in on those patients with high astigmatism or with significant changes in refractive error, there will likely be more who are affected by the condition. Crosslinking must-haves To effectively treat such patients, you first need the right equipment. Dr. Trattler pointed out that one of the big challenges with keratoconus is that while traditional Placido disc topography is accurate at diagnosing mild to moderate keratoconus, once Crossing the crosslinking bridge Corneal collagen crosslinking • September 2016 A 31-year-old female developed post-LASIK ectasia. She underwent epi-on CXL in 2014. On return 2 years, 4 months later, her corneal shape had significantly improved. The difference map demonstrates that the steep inferior part of the cornea became flatter, and the superior part of the cornea became steeper. Source: William Trattler, MD

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