Mengmeng Wang1, Fengju Zhang, Xu Zhao, Yanzheng Song, Miao Zhang. 1. From the *Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Lab, Beijing; and †Hebei Eye Hospital, Hebei Ophthalmology Key Lab, Xingtai City, Hebei Province, China.
Abstract
PURPOSE: The aim of this study was to evaluate riboflavin in rabbit corneas before and after corneal collagen cross-linking (CXL) using confocal laser scanning microscopy. DESIGN: A randomized controlled experimental study. METHODS: The study was divided into 3 parts. In part 1 of this study, 30 eyes from 15 rabbits were used to evaluate riboflavin in de-epithelialized corneas before standard CXL. In part 2, 12 eyes from 6 rabbits were used to compare the differences of riboflavin concentration between standard CXL and transepithelial CXL (TE-CXL). In part 3, 12 eyes from another set of 6 rabbits were used to evaluate 1-day postoperative changes of riboflavin concentration between standard CXL and TE-CXL. Riboflavin concentrations in corneas were evaluated by calculating fluorescence densities with a confocal laser scanning microscope. RESULTS: In part 1, the riboflavin concentration after a 20-minute instillation was 0.036%, and did not reach the safety threshold (0.040%) for standard CXL. In part 2, the riboflavin concentration before TE-CXL was lower than 0.010%, which was significantly lower than standard CXL (P < 0.001). In part 3, corneal fluorescence decreased by approximately 100% (fluorescence quenching) 1 day after standard CXL and approximately 60% 1 day after TE-CXL. CONCLUSIONS: Application of 0.010% riboflavin solution for 30 minutes is essential for standard CXL. TE-CXL is not recommended because the epithelial layers are inadequately permeable to riboflavin during and 1 day after surgery.
PURPOSE: The aim of this study was to evaluate riboflavin in rabbit corneas before and after corneal collagen cross-linking (CXL) using confocal laser scanning microscopy. DESIGN: A randomized controlled experimental study. METHODS: The study was divided into 3 parts. In part 1 of this study, 30 eyes from 15 rabbits were used to evaluate riboflavin in de-epithelialized corneas before standard CXL. In part 2, 12 eyes from 6 rabbits were used to compare the differences of riboflavin concentration between standard CXL and transepithelial CXL (TE-CXL). In part 3, 12 eyes from another set of 6 rabbits were used to evaluate 1-day postoperative changes of riboflavin concentration between standard CXL and TE-CXL. Riboflavin concentrations in corneas were evaluated by calculating fluorescence densities with a confocal laser scanning microscope. RESULTS: In part 1, the riboflavin concentration after a 20-minute instillation was 0.036%, and did not reach the safety threshold (0.040%) for standard CXL. In part 2, the riboflavin concentration before TE-CXL was lower than 0.010%, which was significantly lower than standard CXL (P < 0.001). In part 3, corneal fluorescence decreased by approximately 100% (fluorescence quenching) 1 day after standard CXL and approximately 60% 1 day after TE-CXL. CONCLUSIONS: Application of 0.010% riboflavin solution for 30 minutes is essential for standard CXL. TE-CXL is not recommended because the epithelial layers are inadequately permeable to riboflavin during and 1 day after surgery.
Authors: Arie L Marcovich; Jurriaan Brekelmans; Alexander Brandis; Ilan Samish; Iddo Pinkas; Dina Preise; Keren Sasson; Ilan Feine; Alexandra Goz; Mor M Dickman; Rudy M M A Nuijts; Avigdor Scherz Journal: Transl Vis Sci Technol Date: 2020-05-11 Impact factor: 3.283