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Cheryl Guttman in San Francisco, US
His series comprised 2,809 eyes of 1,477 patients who had undergone either LASIK or PRK for the correction of myopia or myopic astigmatism (spherical errors up to -13 D). The series included two eyes treated for retinal detachment which was identified through the refractive surgery screening exam and 15 eyes with a history of surgery for retinal detachment. All eyes were carefully examined for retinal pathology postoperatively, and during a mean follow-up of 50 months, within a range of 16 to 121 months. Retinal detachments developed in five (0.18%) eyes, none of which had undergone prior retinal surgery. Of the 2,809 treated eyes, two-thirds received PRK and the rest underwent LASIK. The five retinal detachments which occurred during follow-up involved three PRK eyes and two LASIK eyes. Myopia for the PRK eyes ranged from -4.0 to -9.0 D and the mean preoperative myopic errors for the LASIK eyes were -7.0 and -9.0 D respectively. The two retinal detachments in the LASIK eyes occurred at one and three months after surgery. The time to retinal detachment after PRK was eight months in one eye and 12 months in the two others. "The shorter interval between excimer laser surgery and the onset of retinal detachment in the LASIK eyes compared with the PRK eyes suggests some adverse effect of the microkeratome suction. However, no clear-cut conclusions can be made from this observation because of our very low number of cases," Dr Pucci said. He noted that high myopes, defined as eyes with spherical errors greater than -6.0 D, are at increased risk from retinal detachment, with various published studies placing that risk at approximately 0.7% per year. There has been concern about the potential for refractive surgery to worsen their risk, but few studies examining that issue have been performed. "Our current findings are consistent with a previous study from JF Arevalo MD and colleagues who reported a retinal detachment rate of 0.06% after LASIK. Together they support the conclusion that the retinal detachment rate after excimer laser surgery for the treatment of high myopia is not increased, compared with the natural history of unoperated myopic eyes. However, there is a need for multicentre, prospective studies on the incidence of retinal detachment after refractive surgery, especially laser surgery," Dr Pucci said. He initially reviewed 1,688 patients presenting for excimer laser surgery. Of those, 211 were excluded from refractive surgery for reasons of excessive myopia (174), peripheral retinal degeneration (35) or retinal detachment (2). "We do not perform excimer laser surgery in eyes with myopia higher than -13 D and we examine all patients carefully preoperatively for retinal pathology which would require treatment. With two exceptions, the patients with impending or existing retinal detachment declined laser vision correction after their posterior segment surgery," Dr Pucci explained. Management of the retinal detachments involved scleral buckle surgery in all eyes. Posterior vitrectomy with a silicone oil injection tamponade was performed to manage floaters or proliferative vitreoretinopathy in the PRK eyes. The surgeries were successful and four patients had a good visual outcome after surgery while the fifth is still under treatment. Vincenzo Pucci
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