EyeWorld Asia-Pacific September 2015 Issue

45 EWAP REFRACTIVE September 2015 chair in ophthalmology, Cullen Eye Institute, Baylor College of Medicine. However, because wavefront-optimized and wavefront-guided ablations provide excellent outcomes in normal corneas, the role for topography- guided procedures is likely limited to extreme cases, particularly patients with primarily irregular astigmatism. “There are patients you can’t capture with regular wavefront- guided refractive systems, but new wavefront sensors are much more robust. We will need to see head-to-head trials for these more sophisticated wavefront-guided systems that base treatments on the optics of the eye versus topography- guided ablation,” Dr. Koch said. “But it will be helpful to have both of these technologies available.” Dr. MacRae agreed that topography-guided refractive surgery is a therapeutic option, as opposed to a first-line alternative to existing systems. It might prove especially useful in eyes with corneal irregular astigmatism or keratoconus. “It’s a nice backup option for them,” Dr. MacRae said. Stronger corneas? Future precautionary uses for collagen crosslinking in primary laser vision procedures may include any patient where a fragility of the cornea that would predispose him/ her to ectasia is suspected, Dr. Koch said. “We may learn that we can expand our indications for LASIK by pretreating or treating these patients at the time of ablation,” Dr. Koch said. “There are patients that we are reluctant to treat because of suspected or early keratoconus, and those patients are showing good results with a combination of crosslinking and primary surface ablation.” Although collagen crosslinking in primary laser vision procedures has garnered some interest overseas, U.S. surgeons are still waiting for studies demonstrating promised clinical benefits. “It’s compelling that you can in theory not weaken the structural integrity, which goes along the same line of thought as the SMILE procedure to make it as strong as a standard natural PRK procedure,” Dr. Kraff said. However, prospective clinical trials are needed to evaluate that. A better understanding is also needed regarding the potential impact of crosslinking on the final refractive results, Dr. Koch said. “Patients are not going to be happy if we strengthen their cornea but they end up with a residual refractive error,” Dr. Koch said. Reversible treatment As a clinical investigator for the KAMRA (AcuFocus, Irvine, Calif.) clinical trials, Dr. Kraff can see a role for the removable corneal inlays. However, investigators found during the presbyopia trial that very careful patient selection is key. “If you select patients carefully, the data from the AcuFocus trial suggests that we can generate good results and give patients a corneal presbyopic solution using an inlay medical device,” Dr. Kraff said. That focus likely means that there aren’t as many good candidates for the device as one might think—for instance, those who can tolerate having 1 eye treated for presbyopia in some manner. Future applications may include treating patients who have had prior refractive surgery and who are now presbyopic or performing simultaneous LASIK and inlay application. “As we get more comfortable with this procedure in a commercial environment, we’ll learn a lot more about who are the absolute best patients for this and we’ll learn who are the best patients to offer this to as a presbyopic solution,” Dr. Kraff said. “There are no other options beyond premium IOLs and refractive lens exchange or a monovision option in a corneal refractive procedure.” Another promising technology is the Raindrop (ReVision Optics, Lake Forest, Calif.), Dr. Koch said. International data for implantation of the non-dominant eye in presbyopes show excellent results in providing good reading vision with minimal change in uncorrected distance acuity. It appears to be a forgiving and readily accepted option, he said. Mapping the future Another emerging technology that could prove helpful is epithelial thickness mapping in laser vision correction, according to Dr. Koch. This could be an important tool for screening for early forms of keratoconus. Availability of epithelial thickness indices developed for OCT may provide a better way to screen for keratoconus in its early forms. “The other potential role could be in enhancements. When a patient has regression or progression of the effect, you can look at the epithelial thickness profile and try to understand whether it was a stromal change or had something to do with the epithelium,” Dr. Koch said. “With time we might learn how to create treatments that are more stable and also better understand how to more accurately enhance patients who had an unexpected refractive change.” EWAP Editors’ note: Dr. Koch has financial interests with Alcon (Fort Worth, Texas), Abbott Medical Optics (Abbott Park, Ill.), and ReVision Optics. Dr. Kraff has financial interests with Abbott Medical Optics. Dr. MacRae has financial interests with Bausch + Lomb (Bridgewater, NJ). Contact information Koch : dkoch@bcm.edu Kraff : ckraff@kraffeye.com MacRae : Scott_MacRae@urmc.rochester.edu “We need to be cautious about what type of expectations we create.” - Scott M. MacRae, MD