Deep Lamellar Endothelial Keratoplasty (DLEK): How thick and uniform is the manual stromal dissection and does it affect vision?

Abstract

Abstract: : Purpose:Deep lamellar endothelial keratoplasty (DLEK) replaces the endothelium utilizing a deep stromal manual dissection for removal of the recipient endothelium and posterior stroma. The histology of the recipient disc was evaluated for uniformity of thickness and smoothness of the stromal recipient interface. Histology was correlated with vision at the 6–month time gate. Methods:Fifty–five recipient posterior lamellar discs from 58 consecutive DLEK surgeries were evaluated using a Leica DM IRB research microscope coupled with Image–Pro Plus Version 4.5 for Windows after standard hematoxylin and eosin staining. Disc thickness was measured at the center and at each end of the 8 mm discs to determine uniformity of the specimen. Discs were separated into two categories depending on whether they followed the corneal anatomic plane (having smaller central thickness readings compared to peripheral readings) or whether they were "wedge" discs in which one end of the recipient tissue was thinner than the center. A "smoothness" grading system of 1 to 4 was applied to the stromal dissection surface based upon the frequency of fragmented lamellae. Visual acuity at the 6–month time gate was correlated with histology. Results:The average vision at 6 months was 20/50 (range, 20/25 to 20/400). The average central thickness of the specimens was 171.5 microns (range, 17.2 to 396.1 microns) and this correlated significantly with vision. Recipient discs with thinner central readings had a better visual outcome (r=0.3139, P=0.0196). The average difference in thickness between the two ends of a disc was 70.1 microns (SD 58.9 microns) and this did not correlate with visual acuity (r=–0.0011, P=0.9936). Thirty–one of 55 discs followed the anatomic plane. Conversely, 24 of 55 discs were "wedges." There was no significant difference between visual acuity of anatomically contoured discs and wedge discs (P =0.932). The average smoothness of the stromal surface was good at 2.00 (SD 0.88) and did not correlate with visual outcome (r=–0.1942, P=0.1554). Conclusions:This is the first report of histology of recipient disc quality after DLEK surgery. While variance in disc uniformity and smoothness occurs with manual dissection, it was not a major factor in visual acuity after DLEK surgery. Dissection of recipient discs with thinner central readings, however, did correlate with better vision.

Keywords: transplantation • pathology: human • cornea: clinical science