Abstract
Purpose :
Descemet’s membrane endothelial keratoplasty (DMEK) is surgically challenging due to lack of rigidity and tight scrolling of the tissue. Corneas from older donors are preferred for DMEK surgery since Descemet’s membrane thickens and becomes more rigid with age. This study compares the thickness of central and peripheral Descemet’s membrane in human donor corneal tissue to evaluate the potential impact of eccentric trephination on graft thickness and rigidity.
Methods :
Human corneal tissue was procured from deceased donors according to standard protocol. Tissues were preserved in Optisol-GS corneal storage media prior to formalin fixation. Corneas were bisected centrally and underwent standard tissue processing and microtome sectioning. Periodic acid-Schiff stain was used to highlight Descemet’s membrane. Images were acquired at 100x magnification using live image capture with Olympus “cellSens” imaging acquisition software. The 2 peripheral terminations of Descemet’s membrane were identified near the trabecular meshwork. 3 sequential measurements of the peripheral Descemet’s membrane thickness were obtained 200 microns from the periphery to avoid aberration attributable to Hassall-Henle bodies. The cornea's center was identified, and 3 sequential measurements of the central Descemet’s membrane thickness were obtained. This process was repeated for both corneal cross-sections on each slide. Student’s T-test was used to compare the central versus peripheral Descemet’s membrane thickness.
Results :
Tissue from 7 human donor corneas were analyzed. Mean peripheral Descemet’s membrane thickness was 1.59x greater than the mean central Descemet’s membrane thickness. The mean peripheral Descemet’s membrane thickness was 11.97 microns (range: 16.65 to 9.03 microns, SD = 2.08 microns), whereas the mean central Descemet’s membrane thickness was 7.49 microns (range: 5.53 to 10.70 microns, SD = 1.52 microns). Student’s T-test performed comparing the mean peripheral versus mean central Descemet’s membrane thickness was highly statistically significant with p<0.001.
Conclusions :
Descemet’s membrane thickness has implications for DMEK graft rigidity and intra-operative manipulation. These data suggest that Descemet’s membrane is thicker in the peripheral rather than central cornea. Eccentrically trephinated DMEK grafts may offer more rigidity by incorporating more of the thicker periphery.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.