Delayed onset keratectasia following laser in situ keratomileusis.

We present a case of unilateral iatrogenic keratectasia developing 10 months after bilateral laser in situ keratomileusis (LASIK) involving enhancement surgery using a broad-beam excimer laser (Summit Apex) to treat 6.6 diopters (D) of myopia. The ectasia progressed rapidly over the subsequent 12 months. The surgeon did not measure preoperative pachymetry, but preoperative topography and corneal measurements did not reveal underlying keratoconus or forme fruste keratoconus. Corneal transplantation was required for final visual rehabilitation. Light microscopy of the button revealed no underlying inflammation, which suggests biomechanical corneal weakening as the cause of the ectasia. Scanning electron microscopy showed the dramatic thinning seen clinically. latrogenic keratectasia appears to be a possible complication of LASIK.