Abstract
Abstract: :
Purpose: The purpose of this investigation is to characterize the wavefront aberrations in patients who undergo DLEK and to compare these findings with the wavefront aberrations present in PKP patients. In addition, we want to determine if higher order wavefront aberrations limit the final visual acuity in DLEK patients. Methods: The pre and postoperative wavefront aberrations were measured on 40 consecutive DLEK patients using the Tracey iScan®, which allows wavefront and topographic assessment. Five patients had a 9 mm incision DLEK, while 28 had a 5 mm incision DLEK. Six were converted to PKP and serve as a comparison group. Results: Preliminary results show that the mean total RMS value (u) at 6 months was 0.514, 1.156, and 1.423, while the higher order component was 0.197, 0.400, and 0.5455 in the 5 mm DLEK, 9 mm DLEK, and PKP groups respectively. Third term coma was most commonly seen preoperatively in each group, consistent with central corneal thickening associated with Fuchs’ dystrophy or bullous keratopathy. As time progressed, third term trefoil was most commonly displayed. By six months, there was a return of third term coma, but to a much lesser degree than preoperatively. Mean best–corrected Snellen vision at 6 months was 20/45 (5 mm DLEK) and 20/33 (9 mm DLEK and PKP). Conclusions: DLEK induces fewer higher order wavefront aberrations than PKP, however this does not translate into improved Snellen vision as one would expect. This research shows that there may be more important factors involved which limit the final visual outcome in DLEK. Correlation of the interface opacity with Snellen vision and wavefront analysis may be necessary to completely understand the visual aberrations that occur after DLEK.
Keywords: cornea: clinical science • cornea: endothelium • imaging/image analysis: clinical