Z HOT TOPIC Z 

Authors: Colten Wendel, Jaime C. Sklar, Angela Zhang, Nir Sorkin, Clara Chan, Sonia Yeung, Alfonso Iovieno
Author Disclosure Block: C. Wendel: None. J.C. Sklar: None. A. Zhang: None. N. Sorkin: None. C. Chan: None. S. Yeung: None. A. Iovieno: None.

Abstract Body:

Purpose: To assess the change in corneal transplant rates for keratoconus (KCN) since the start of crosslinking (CXL) in Ontario and British Columbia in 2008.
Study Design: Retrospective chart review of all corneal transplants performed between 1998 and 2016 at the Eye Bank of Canada - Ontario & British Columbia divisions.
Methods: A retrospective chart review was conducted, and data were stratified by diagnosis, where each was labelled as KCN or other. Type of transplant, age, gender, and pre-operative visual acuity were recorded. Data were stratified by diagnosis, where each was labelled as KCN or other. Data was analyzed using a chi-square test of independence.
Results: 29,348 charts were reviewed. Chi-square analysis demonstrated a significant change in the proportion of transplants performed for KCN (p<2.2x10^-), where a decrease was observed after (range:16.8%-6.54%; mean:10.94%) compared to before CXL (range:16.55%-12.39%; mean: 14.14%). However, there has been no change in the raw number of grafts required for KCN across our study interval (p=0.5) while a marked increase in endothelial keratoplasties was observed between the two time points (p<0.001). There were no statistically significant differences in the mean age, gender, or pre-operative visual acuity between the patients in the two periods. Additionally, there has been an increasing trend towards using deep anterior lamellar keratoplasty over penetrating keratoplasty over time in the two centres.
Conclusions: Since the introduction of CXL in Ontario and British Columbia, there has been no change in the number of transplants over time. The observed decrease proportion of transplants for KCN appeared to be secondary to an increase in endothelial keratoplasty, rather than a true decrease in the requirement for keratoplasty in KCN.