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Excimer Laser Smoothing of Endothelial Keratoplasty Grafts

Cleary, Catherine MD*,†; Liu, Ying MD*,†,‡; Tang, Maolong PhD*,†,§; Li, Yan PhD*,†,§; Stoeger, Christopher CEBT; Huang, David MD, PhD*,†,§

Cornea:
doi: 10.1097/ICO.0b013e31822444a7
Basic Investigation
Abstract

Purpose: To use excimer laser smoothing passes to reshape Descemet-stripping automated endothelial keratoplasty (DSAEK) endothelial grafts and to evaluate the effect on the donor endothelium.

Methods: The stromal surface of microkeratome-cut DSAEK grafts was smoothed using excimer laser smoothing passes with masking fluid. Excimer laser hyperopic ablation was used to improve the uniformity of graft thickness within the optical zone. Fourier-domain optical coherence tomography was used to measure endothelial graft pachymetry, plan ablations, and evaluate donor contour. Vital dye staining was performed to assess endothelial cell damage. Scanning electron microscopy images of stromal surfaces were graded on a 5-point scale by masked observers to evaluate surface roughness.

Results: Four grafts underwent excimer laser smoothing. Vital dye staining showed no endothelial damage. Microkeratome-cut surfaces treated with laser smoothing (mean grade = 2.04) were smoother than nonsmoothed microkeratome-cut surfaces (mean grade = 4.07; P < 0.01), surfaces that underwent dry laser ablation (mean grade = 3.63; P < 0.01) and manually dissected interfaces (mean grade = 4.75; P < 0.0001). No difference was observed between stromal beds created by peeling Descemet membrane (mean grade = 1.64) compared with surfaces produced by microkeratome cutting followed by laser smoothing (mean grade = 2.04; P = 0.14). One graft underwent combined excimer smoothing and peripheral hyperopic ablation. The center–periphery thickness difference was 15 μm before ablation and 4 μm afterward.

Conclusions: Laser smoothing passes can be used to improve the contour and smoothness of DSAEK grafts without damaging donor endothelial cells. Clinical trials are needed to determine whether reshaping donors using excimer laser can deliver improved visual outcomes after DSAEK.

Author Information

*Doheny Eye Institute and

Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, CA

State Key Ophthalmic Laboratory, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China

§Center for Ophthalmic Optics and Lasers (www.COOLLab.net), Casey Eye Institute, Oregon Health and Science University, Portland, OR

Lions Eye Bank of Oregon, Portland, OR.

Supported by National Institutes of Health grants (R01 EY017723 and EY018184), an unrestricted grant from the Research to Prevent Blindness, Inc, and endowment funding from the Skilling Foundation and from the Charles C. Manager III, MD Chair in Corneal Laser Surgery.

Dr. Catherine Cleary is supported by a grant from the Irish College of Ophthalmologists.

Dr. Ying Liu is supported by a grant from the China Scholarship Council.

Drs. Y. Li, M. Tang, and D. Huang receive grant support from Optovue, Inc.

D. Huang received stock options, travel support, and a patent royalty from Optovue Inc. He also received a royalty from a patent on optical coherence tomography licensed to Carl Zeiss Meditec, Inc.

Reprints: David Huang, Center for Ophthalmic Optics and Lasers, Casey Eye Institute, Oregon Health and Science University, 3375 S.W. Terwilliger Boulevard, Portland, OR 97239-4197 (e-mail: davidhuang@alum.mit.edu).

Received September 16, 2010

Accepted May 11, 2011

© 2012 Lippincott Williams & Wilkins, Inc.