1. Comparison of Endothelial Keratoplasty (EK) Visual Outcomes with OCT Derived Corneal Thickness Measurements Authors Abraham K. Sleem, MD Robert L. Schultze, MD Robert A. Eden, MD William Yang, MD Nadia Haqqie, BS No Financial Interest in Study Material

2. Introduction The advent of Descemet’s Stripping with Automated Endothelial Keratoplasty (DSAEK) has changed the current approach to the treatment of endothelial diseases. The advantages of this procedure include shorter recovery time, less chance of sight-threatening complications, improved structural integrity of the cornea, and less irregular astigmatism compared to penetrating keratoplasty. While recent models and studies attempt to predict refractive outcomes based on donor tissue properties, this study investigates the relationship of the host and donor thickness related to best corrected visual acuity outcome.The advent of Descemet’s Stripping with Automated Endothelial Keratoplasty (DSAEK) has changed the current approach to the treatment of endothelial diseases. The advantages of this procedure include shorter recovery time, less chance of sight-threatening complications, improved structural integrity of the cornea, and less irregular astigmatism compared to penetrating keratoplasty. While recent models and studies attempt to predict refractive outcomes based on donor tissue properties, this study investigates the relationship of the host and donor thickness related to best corrected visual acuity outcome.

3. Purpose To determine the impact of pre-operative corneal thickness, as well as, post- operative donor, recipient, and overall corneal thickness on EK visual outcomes.

4. Methods 47 eyes without visually significant retinal or optic nerve pathology underwent DSAEK by one surgeon (RLS).47 eyes without visually significant retinal or optic nerve pathology underwent DSAEK by one surgeon (RLS). Pre-operative corneal pachymetry was measured by ultrasound.Pre-operative corneal pachymetry was measured by ultrasound. Post-operative recipient, donor and overall corneal thickness were determined utilizing the Visante OCT at one year.Post-operative recipient, donor and overall corneal thickness were determined utilizing the Visante OCT at one year.

5. Methods Mean BSCVA of two groups stratified by donor thickness was compared using the student t-test.Mean BSCVA of two groups stratified by donor thickness was compared using the student t-test. Post-operative BSCVA was also correlated with each measured thickness utilizing regression analysis.Post-operative BSCVA was also correlated with each measured thickness utilizing regression analysis.

6. Surgical Technique DSAEK donor buttons prepared with 300 head on Moria ALTK systemDSAEK donor buttons prepared with 300 head on Moria ALTK system All Donors punched to 8mmAll Donors punched to 8mm Donor buttons inserted through 5 mm woundDonor buttons inserted through 5 mm wound Cornea massage and venting performedCornea massage and venting performed Air bubble maintained for one hour then burpedAir bubble maintained for one hour then burped

7. ParameterAverage Pre-Op Pachymetry709.9±82.9µm Post-Op BSCVA20/35 Post-Op Recipient Bed Thickness 517.6±44.6µm Post-Op Donor Thickness 162.7±38.9µm Post-Op Total Thickness680.3±63.4µm Results: Data Collected

8. Results: Statistical Analysis No correlation between pre-operative pachymetry and BSCVA (p>0.05)No correlation between pre-operative pachymetry and BSCVA (p>0.05) No correlation between host recipient bed thickness and BSCVA (p>0.05)No correlation between host recipient bed thickness and BSCVA (p>0.05) The average post-operative BSCVA was 20/33 and 20/36 for eyes with donor thickness <162µm and ≥162µm, respectively (p<0.04).The average post-operative BSCVA was 20/33 and 20/36 for eyes with donor thickness <162µm and ≥162µm, respectively (p<0.04). No linear correlation between donor thickness and BSCVA (p>0.05)No linear correlation between donor thickness and BSCVA (p>0.05)

9. Results: BSCVA vs Donor Thickness

10. Results: Regression Analysis Results: Regression Analysis No Linear Correlation between BSCVA and Donor Thickness

11. Although the group of eyes that received thinner donors (<162µm) demonstrated statistically significant better post- operative vision on average, the difference was very small.Although the group of eyes that received thinner donors (<162µm) demonstrated statistically significant better post- operative vision on average, the difference was very small. No linear relationship between BSCVA and donor thickness was demonstrated with regression analysis.No linear relationship between BSCVA and donor thickness was demonstrated with regression analysis. Conclusions

12. Discussion No clear linear relationship between post- operative BSCVA and donor thickness was demonstrated, however the group of eyes with the thinner grafts showed only slightly better vision.No clear linear relationship between post- operative BSCVA and donor thickness was demonstrated, however the group of eyes with the thinner grafts showed only slightly better vision. This may suggest that techniques that involve thinner grafts (ex. DMEK) may not necessarily result in better BSCVA.This may suggest that techniques that involve thinner grafts (ex. DMEK) may not necessarily result in better BSCVA.