EyeWorld Asia-Pacific June 2013 Issue

47 EWAP rEfrActivE June 2013 lot of experience,” Dr. Holland said. When crosslinking became available in Canada around four years ago, it had already been discussed in Europe that strengthening the cornea allows physicians to take more tissue off at the time of PRK. The field really opened up with crosslinking, Dr. Holland said, and some have used a combination of crosslinking with topography-guided PRK either simultaneously or sequentially. Dr. Holland has been looking at using the two techniques simultaneously, however, he said some people are still reluctant to accept this because of possible complications. “There are several issues that have limited the wide acceptance of this procedure, and also there’s not a lot of experience with topography-guided PRK,” he said. Dr. Holland said simultaneous topography-guided PRK with crosslinking presents a potential problem in that some patients may become hyperopic from the crosslinking alone and the combination may make them too hyperopic. In addition, he said that topography-guided PRK can cause any change in shape of the cornea to lead to change in the refractive power. “Predicting refractive effect has been the main challenge of topography-guided surgery,” he said. Development and utilization of the topographic neutralizing technique (Vancouver Custom TNT) has helped to increase predictability of the refractive effect that topography-guided treatment will have. Dr. Holland said some of the most rewarding aspects of this technique for both the patient and the doctors have come from patients with ectasia because they are often highly symptomatic and there’s little that can be offered to them if they are contact lens intolerant. “We tend to see the refractive part of the treatment has greater impact for ectasia patients.” “We tell patients that the goal of the treatment is primarily, in both keratoconus and ectasia, to stabilize their progression, and any refractive improvement they get is a bonus,” Dr. Holland said. EWAP Editors’ note: Dr. Holland has financial interests with Alcon, Allergan (Irvine, Calif., USA), and Bausch + Lomb (Rochester, NY, USA). contact information Holland : simon_holland@telus.net