EyeWorld Asia-Pacific June 2014 Issue

45 EWAP rEfrActivE June 2014 Refractive outcomes of topography- guided photorefractive keratectomy with simultaneous crosslinking by Ellen Stodola EyeWorld Staff Writer continued on page 46 Physician’s work looks at this new technology in treating keratoconus A lthough corneal collagen crosslinking remains a much- debated topic and is awaiting FDA approval in the United States, many countries around the world have approved and are using the technique. A number of physicians are exploring ways that crosslinking can be combined with other techniques to treat conditions like keratoconus and ectasia. Simon P. Holland, MD , Pacific Laser Eye Centre, and Department of Ophthalmology, University of British Columbia, Vancouver, B.C., Canada, is exploring options in Canada, having recently published the 1-year results of refractive outcomes of topography-guided photorefractive keratectomy with simultaneous crosslinking to treat keratoconus. Dr. Holland spoke about his work with David T.C. Lin, MD , Department of Ophthalmology, University of British Columbia, at the 2013 American Academy of Ophthalmology meeting. He explained that although it is a controversial area, the goal is to present early results from these procedures. Obviously any change in shape can cause a refractive change of the cornea, Dr. Holland said, and Effect of limited refractive treatment on improving both uncorrected and corrected vision with topography-guided PRK and crosslinking in keratoconus Pre- and postoperative topography with difference map in extreme keratoconus Source (all): Simon P. Holland, MD the combination of topography- guided PRK and crosslinking aims to compensate for the induced astigmatism and refractive error produced by the treatment itself of the regularization of the cornea. Looking at the results He noted that this technique may be a slightly hyperopic treatment, so many patients tend to have a myopic result. Dr. Holland discussed his work on hundreds of eyes over the last 4 years, specifically speaking about the results of 165 eyes that were available for analysis at 12 months or longer follow-up. Of these eyes, about 49% had 20/40 or better uncorrected vision and about 16% were at 20/25 or better. “These were all contact lens intolerant patients,” he said. In about half of these patients, BCVA improved, with about a quarter improving by two lines or better. Complications included epithelial healing with subsequent haze, HSV keratitis and delayed healing, and two patients required penetrating keratoplasty so far, Dr. Holland said. “Most of our patients are remaining myopic through the follow-up rather than hyperopic,” he said, noting that there is some regression in results. But overall the results seem to be showing satisfactory improvement for patients’ symptoms and vision with close to half of the patients with 20/40 or better vision and almost a third of the patients gaining two lines or more, Dr. Holland said. This could be a useful option for keratoconus in the future, he said, even though it is a controversial area of treatment. “We need to continue with the long-term follow-up to know whether we’re doing the best thing for [the patients],” he said. Why combine topography- guided PrK and crosslinking? Dr. Holland spoke about using topography-guided PRK with crosslinking and what still needs to be explored. PRK has been used for keratoconus since the introduction of the excimer laser in Canada. However, it was more for nodules that would occur at the apex of the cone in an effort to flatten the