Abstract
Purpose: :
Descemet’s Stripping Endothelial Keratoplasty (DSEK) has become the standard of care for corneal endothelial insufficiency, offering fewer complications than Penetrating Keratoplasty (PK). However, there is concern that endothelial cells are injured during this procedure, and increased endothelial cell loss after DSEK has been noted as compared to PK. Endothelial function after DSEK has not been directly measured in vivo to ascertain the impact of this cell loss. This study examines endothelial cell function after DSEK by measuring corneal deturgescence following a contact lens challenge.
Methods: :
Subjects having undergone successful DSEK were recruited under an IRB approved protocol. Baseline SDOCT of the grafted corneas was performed. Enrolled subjects then wore a standardized soft contact lens with a closed eye for two hours, after which corneal deturgescence was followed with SDOCT imaging every 20 minutes for three hours. For each imaging time point, average corneal thickness over the central three millimeters was calculated. An exponential decay model was fit to the deturgescence curve, and the decay model was used to determine the percent recovery per hour (deturgescence rate) as well as the time to 95% recovery in thickness.
Results: :
Five subjects were enrolled (mean age: 64.6 years, mean time since surgery: 280 days). Their deturgescence curves fit the exponential decay model with an R value of 0.962±0.026 (mean±SD). The average percent corneal thickness increase due to contact lens challenge was 4.42±1.61%. The percent recovery per hour was 52.6±8.1%, and the calculated time to 95% recovery was 248±58 minutes.
Conclusions: :
The functional response of the corneal endothelium to a contact lens challenge in this post-DSEK population is comparable to what would be expected for patients in this age group with normal healthy corneas. Previous studies in normal individuals found percent recovery per hour to be 62.5±7.6% (mean age 50.9 years) and 34.2±6.4% (mean age 71.9 years)1,2. This suggests that despite endothelial cell injury from the DSEK procedure, there is no compromise of endothelial function.[1] Bourne WM. Functional Measurements on the Enlarged Endothelial Cells of Corneal Transplants. Trans Am Ophthalmol Soc. 1995;93:65-79; discussion 79-82.[2] Polse KA et al. Age Differences in Corneal Hydration Control. Invest Ophthalmol Vis Sci. 1989 Mar;30(3):392-9.
Keywords: cornea: endothelium • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • cornea: clinical science