Eyeworld

EW FEATURE 74 Update on crosslinking • September 2017 AT A GLANCE • CXL is the current paradigm used to stabilize the cornea in patients with keratoconus. • The global consensus on keratoco- nus and ectatic diseases achieved consensus on diagnosis, nonsurgical treatment, and surgical treatment of keratoconus. • Experts do not agree on the ben- efits of accelerated CXL protocols compared to the standard Dresden protocol. • Shorter ophthalmic surgery times increase patient comfort during the procedure. by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer Is using the standard low intensity protocol for corneal crosslinking still the best way to go? O verall, shorter ophthalmic surgical techniques are preferable and can be far more comfortable for pa- tients, but do they forfeit safety and efficacy? When it comes to corneal crosslinking (CXL), some experts think it might pay to take your time. EyeWorld spoke with two specialists to understand the status of CXL internationally and discuss current viewpoints. Corneal CXL combines the use of riboflavin (vitamin B2) drops and ultraviolet (UV) light to reshape and stiffen the cornea in patients with corneal ectasias, such as keratoco- nus, a degenerative non-inflamma- tory disease of the cornea in which the central or paracentral cornea undergoes progressive thinning and steepening, causing irregular astig- matism. The procedure has been performed in Europe for roughly 15 years, but has only been FDA approved since 2016. Current paradigm "Corneal crosslinking internation- ally has been transformed into the current paradigm for stabilizing progressive keratoconus and ec- tasia," 1 said John Kanellopoulos, MD, medical director, LaserVision. difficulty in contact lens fitting and complications arising from poorly fitting lenses. Rigid contacts were recommended in cases of unsatisfac- tory vision with glasses. CXL is indicated in the treat- ment of keratoconus with docu- mented clinical progression, as well as for eyes with keratoconus that have previously received other forms of corneal surgery. Although the panel did not reach a consensus regarding the use of CXL in sub- clinical keratoconus, they did agree that as long as there is evidence of progression, there should be no age gr Institute, Athens, Greece, and clinical professor of ophthalmology, New York University Medical School, New York. "In several parts of the world, the clinical consensus is that it should be used prophylactically in high risk patients, for instance, young patients less than 25 who show even the subtlest clinical signs of keratoconus, such as topographic, topometric, or epithelial mapping irregularities that are consistent with early keratoconus. 2 With the FDA approval of corneal crosslinking last year, it is now a globally established procedure for this purpose." 3 Before ophthalmologists can treat keratoconus and decide on surgical or nonsurgical measures, ectasia needs to be defined and physicians require guidelines. Dr. Kanellopoulos referred to the global consensus on keratoconus and ectat- ic diseases 4 that gives definitions and recommendations for the treatment of keratoconus to help physicians navigate their way through the various controversies in diagnosis and management. The global con- sensus project involved the use of a modified Delphi technique, followed by three questionnaire rounds, as well as face-to-face meetings with 36 expert ophthalmology panelists, to achieve consensus on definition/di- agnosis, nonsurgical treatment, and surgical treatment of keratoconus, where a two-thirds majority was required for consensus. The consensus project defined ectasia progression as a consistent change over time in at least two pa- rameters: steepening of the anterior corneal surface, steepening of the posterior corneal surface, or thin- ning and/or an increase in the rate of corneal thickness change from the periphery to the thinnest point, which are above the normal vari- ability (noise) of the measurement system. Although progression is often accompanied by a decrease in BSCVA, a change in both UCVA and BSCVA is not required to document progression. The panel agreed that specific quantitative technology and machine-specific data were lacking to further define progression. They recommended that examinations in younger patients be shorter and in- volve the use of the same measuring platform for consistency. According to the global con- sensus panelists, halting disease progression and visual rehabilita- tion were the two most important goals of nonsurgical therapy. To this end, they advised avoiding eye rubbing but supported the use of topical anti-allergic medications and lubricants. The panelists agreed that there was no direct relation- ship between keratoconus and dry eye and that preservative-free drops were preferable. The use of contact lenses for aesthetic purposes was contraindicated due to the increased Corneal crosslinking: Fast and furious versus low and slow continued on page 76 Slit lamp photograph of an eye immediately after epithelium-off CXL. There is a bandage soft contact lens in place. Mild diffuse post-CXL corneal haze and the yellow of the riboflavin can still be seen. Slit lamp photograph of the same eye 2 weeks after epithelium-off CXL. There is mild diffuse post-CXL corneal haze. Vogt's striae of keratoconus can be seen at the inferior pupil. Source: Christopher J. Rapuano, MD

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