Retinal problems after LASIK rare

Baltimore-Although millions of patients worldwide have undergone LASIK to treat myopia, serious complications sometimes present postoperatively, including endophthalmitis, retinal tears, retinal detachments, retinal hemorrhages, choroidal neovascularization, and macular holes, said J. Fernando Arévalo, MD, FACS, at the Current Concepts in Ophthalmology meeting.

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. Arévalo, 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.”

Several publications previously reported an association between LASIK and retinal detachments, according to Dr. Arévalo. He and his colleagues reported the development of vitreoretinal pathology after LASIK in 0.06% of cases, including 14 cases of rhegmatogenous retinal detachment.

To expand further the existing knowledge about retinal complications after LASIK, Dr. Arévalo 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. Arévalo 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?”

Retinal detachment

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. Arévalo 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.”

He and his colleagues found that maculopathies developed in 32 eyes of 30 patients who had a unilateral full-thickness macular hole (20 eyes of 19 patients; frequency, 0.02%) or subfoveal choroidal neovascular membranes (12 eyes of 11 patients; frequency, 0.01%) after LASIK for myopia.

The macular holes developed between 1 and 30 months (mean, 7.5 months) after LASIK; the subfoveal choroidal neovascular membranes developed between 1 and 60 months (mean, 25.2 months) after LASIK. The macular holes developed in patients with myopia ranging from –0.50 to –15.25 D (average, –7.9 D); the subfoveal choroidal neovascular membranes developed in patients with myopia ranging from –6.5 to –25.5 D (average, –15.1 D). Most patients in whom macular holes and choroidal neovascularization developed were women, according to Dr. Arévalo.

Of 14 eyes with macular holes that underwent vitreous surgery, six had visual acuity of 20/100 or worse and five had visual acuity of 20/40 or better. Four of five cases with a macular hole and a posterior pole retinal detachment underwent macular hole surgery. All eyes had a final visual acuity of 20/150 or worse.

“The reasons for poor visual acuity included the development of cataract and the presence of chorioretinal atrophy,” he said.

Nine eyes with choroidal neovascular membranes were treated with photodynamic therapy, and four of these had a visual acuity improvement of two to five lines. Two eyes had a worse visual acuity by two to four lines.

“Improvement or stability of visual acuity was seen in 77.7% of cases,” Dr. Arévalo reported.

Cases of macular hemorrhage also occur after LASIK.

“Some of these cases are visually significant if the hemorrhages are located in the fovea,” Dr. Arévalo commented.

Corneoscleral perforations also can develop, but in fewer patients. Dr. Arévalo reported two cases of corneoscleral perforation, with an incidence of 0.006%.

Displacement of the corneal flap can occur during vitrectomy and results in poor visual acuity. Flap displacement can occur as late as 69 months after LASIK, he noted.

“In cases of retina surgery after LASIK, if corneal debridement is necessary, it must be done from the hinge to the opposite side to avoid flap displacement,” he said.

Dr. Arévalo noted that Chan and Lawrence reported that LASIK has features that may induce postoperative changes in the vitreoretinal interface.

“The incidence of choroidal neovascularization and macular holes is low, and the majority of cases develop in women. LASIK is a safe procedure with a low incidence of vitreoretinal complications,” Dr. Arévalo said. “Because of the potential for complications, a dilated fundus examination is even more important in every patient whose visual acuity after LASIK is not as good as expected. The goal is to avoid delay in referring a patient who develops problems post-LASIK to a vitreoretinal specialist.”OT