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Although millions of patients worldwide have undergone LASIK to treat myopia, the complication rate is very low. The problems that do arise postoperatively, however, can be serious and include endophthalmitis, retinal tears, retinal detachments, retinal hemorrhages, macular holes, and choroidal neovascularization.
The prevalence of myopia in the United States has been reported to range from 25% to 46.4%; the prevalence in Asia, Africa, and the Pacific Islands might be higher and lower.
"LASIK has become a very popular option for treating patients with low and moderate myopia," said Dr. Arevalo, director, Clinica Oftalmologica Centro Caracas, the Arevalo-Coutinho Foundation for Research in Ophthalmology, and professor of ophthalmology, University of Los Andes, Caracas, Venezuela. "However, the procedure has been associated with retinal complications."
To expand further the existing knowledge about retinal complications after LASIK, Dr. Arevalo and colleagues undertook a large retrospective analysis that included 83,938 eyes that underwent LASIK. The patients had undergone LASIK between March 1996 and March 2004 in seven institutions in Venezuela, Colombia, Puerto Rico, Spain, and the United States. All patients underwent LASIK to treat myopia ranging from –0.75 to –29 D (mean, –6.19 D). The follow-up ranged from 6 to 84 months (mean, 65 months).
The average patient age was 37.8 years (range, 16 to 60 years). About two-thirds of the patients were men.
Dr. Arevalo raised a question about the pathogenesis of retinal detachment in these eyes: "When placing a suction ring on these eyes, what is happening inside the eyes? Is there a chance that the retinal complications that develop after LASIK are associated with the procedures performed during the surgery?"
Data analysis showed that 40 eyes of 34 patients (0.04%) developed retinal detachments; 9% of the 40 eyes underwent LASIK enhancements. A rhegmatogenous retinal detachment developed between 12 days and 60 months postoperatively (mean, 16.3 months). The refractive errors in patients in whom retinal detachments developed ranged from –1.5 to –16 D (mean, 8.75 D).
Vitreoretinal surgery was performed at a mean of 56 days, and the mean follow-up after this procedure was 14 months. Vitrectomy was performed in 19 cases, scleral buckling in 10 cases, argon laser retinopexy in six cases, pneumatic retinopexy in two cases, and cryoretinopexy in one case.
Of the 40 eyes that developed retinal detachments, 38.7% had a final visual acuity of 20/40 or better, 77.4% had a final visual acuity of 20/200 or better, 22.6% had a final visual acuity of 20/200 or worse.
The final visual acuity improved two or more lines in 51.6% of eyes, Dr. Arévalo said.
"The main reasons for poor visual acuity included proliferative vitreoretinopathy, epiretinal membrane, chronic rhegmatogenous retinal detachment, new breaks, cataract, and displaced flap," Dr. Arevalo noted.
Anatomic success was achieved after one surgery in 87.1% of cases. Three eyes required one to three re-operations to achieve anatomic success. With re-operations, anatomic success was achieved in 90.3% of cases.
"In most cases, macular holes are idiopathic and age related," Dr. Arévalo continued. "However, macular holes also can be related to myopia, trauma, scleral buckling procedures, pneumatic retinopexy, and vitrectomy."