Photorefractive keratectomy in eyes with atypical topography.

Laser correction of refractive errors is one of the most effective surgical procedures today. Even so, the selection of patients who will have the outcomes they expect remains a major challenge. Corneal ectasia, a frustrating problem that can occur naturally with diseases such as keratoconus, has also been reported after refractive surgery. This review addresses the issues surrounding the use of surface refractive surgery in patients who may have atypical topography, which is a risk factor for ectasia. At present, available tests for predicting future corneal stability can give false positives and false negatives. Although the technology for treating irregular corneal astigmatism has improved, results in eyes with irregular astigmatism are less predictable than in eyes with regular astigmatism, even when wavefront- and topography-driven treatments are used. An increased risk for corneal instability may be associated with laser vision correction (LVC), although instability is generally thought to be less of a risk with surface ablation or photorefractive keratectomy than with laser in situ keratomileusis. Surface LVC has shown good success in improving uncorrected distance visual acuity with a relatively low rate of complications, even in eyes with topographic irregularities.