EyeWorld India June 2013 Issue

46 EWAP rEfrActivE June 2013 Comparison of a patient’s preoperative and postoperative results using topogra- phy-guided PRK with corneal crosslinking to treat ectasia. Patients show improve- ment in UCVA and correction of astigmatism, and Drs. Holland and Lin suggest that this technique has promise for the future. Source: Simon Holland, MD Topography-guided PRK with simultane- ous crosslinking could be future solution for those with ectasia and keratoconus by Ellen Stodola EyeWorld Staff Writer Early results with the procedure show promise E arly results for topography-guided photorefractive keratectomy with simultaneous corneal crosslinking show promise as a plausible treatment for ectasia after LASIK and keratoconus, according to work being done by Simon Holland, MD , and David TC Lin, MD , Pacific Laser Eye Centre, and Department of Ophthalmology, University of British Columbia, Vancouver, BC, Canada. Though there are still many obstacles to work around, Dr. Holland said results are promising, and there have been improvements for patients when using two different laser platforms. “We haven’t seen any progression of ectasia up to three years now,” he said. He said that early results show promise as an effective treatment for highly symptomatic patients. During the 2012 American Academy of Ophthalmology meeting in Chicago, Dr. Holland spoke at Refractive Subspecialty Day about his paper on “Topography-Guided Photorefractive Keratectomy and Crosslinking for Ectasia After LASIK.” In his talk, he discussed early results seen by he and Dr. Lin. “Our plan was to evaluate early results of topography guided-PRK with simultaneous crosslinking for ectasia after LASIK,” Dr. Holland said at the meeting. He went on to explain that the process involved two lasers, one that has been used for just a short period of time and one that has been used for more than 10 years. The results that Dr. Holland talked about involved a study of 29 eyes, 25 of which were treated with a WaveLight Allegretto Wave laser (Alcon, Fort Worth, Texas, USA/Hünenberg, Switzerland) and four with an IVIS laser (IVIS Technologies, Taranto, Italy). The paper’s abstract indicates that 13 of the 19 eyes that were treated with the WaveLight laser “had sufficient data at six months for analysis.” Significant results of the studies included 54% of those analyzed showing UCVA of 20/40, an improvement from the 46% that demonstrated this preoperatively. In addition, the mean reduction in astigmatism was 2.69 D. “Combining results for both lasers, all but three patients symptomatically improved,” the abstract says. Dr. Holland recently presented further on the results of topography-guided PRK with crosslinking at a meeting in Quebec in February, which he said was a continuation of the results presented at AAO. His presentation outlined some of the challenges that arise when using topography-guided photorefractive keratectomy. These issues included induced myopia with the WaveLight laser, the depth of treatment, the lack of effective measure of corneal tissue tensile strength and a simple method of symptom assessment. When looking specifically at the combination of topography- guided PRK with simultaneous collagen crosslinking, questions arose about zone expansion and how deep of a treatment would be involved. The refractive effect of shape change and symptomatic improvement were also factors to consider. Dr. Holland’s more recent presentation discussed analysis of outcomes in post-LASIK ectasia after six months or longer, looking at 37 eyes and using the WaveLight laser. In these results, 23 of the patients completed six months or longer of postoperative treatment. Of these 23, 70% showed a UDVA of 20/40 or greater. The mean reduction of astigmatism for these patients was 1.99 D. All but two of these patients symptomatically improved, and the results showed no progression of ectasia up to two years. Conclusions in Dr. Holland’s most recent presentation maintain that many challenges still remain in the discussion of topography-guided photorefractive keratectomy and simultaneous collagen crosslinking, but early results support the findings that it can be safe and effective. “We’ve been doing topography-guided PRK for irregular corneas since 2002 in our clinic so we had quite a