Modulation of central corneal thickness by various riboflavin eyedrop compositions in porcine corneas

PURPOSE: To evaluate the modulatory effect of various riboflavin 0.1% and 0.2% compositions on the central corneal thickness (CCT) in fresh porcine corneas. SETTING: Department of Ophthalmology, Johannes Gutenberg University of Mainz, Mainz, Germany. DESIGN: Experimental study. METHODS: The OCT in freshly enucleated porcine globes was measured by ultrasound pachymetry before and after (if applicable) deepithelialization and every 10 minutes thereafter during 120 minutes of eyedrop application. In Groups 1 and 2 (controls), no eyedrops were applied. In Groups 3 and 4, isotonic riboflavin eyedrops were used. In Groups 5 to 9, hypotonic riboflavin eyedrops were given. In Groups 10 and 11, preparations for transepithelial crosslinking were applied. In Groups 2 to 9, deepithelialization was performed. The final OCT in the groups was compared by analysis of variance. RESULTS: One hundred ten freshly enucleated porcine globes were used. The mean final OCT compared with preoperative values was 97% +/- 4% (SD) in Group 1, 91% +/- 4% in Group 2, 66% +/- 5% in Group 3, 151% +/- 13% in Group 4, 65% +/- 2% in Group 5, 105% +/- 3% in Group 6, 120% +/- 4% in Group 7, 130% +/- 4% in Group 8, 132% +/- 4% in Group 9, 114% +/- 2% in Group 10, and 114% +/- 4% in Group 11. The differences between Group 1 and each of Groups 3, 4, 5, 7, 8, and 9 were statistically significant (P<.05). CONCLUSION: There was considerable variation in the final OCT as a result of varying riboflavin eyedrop compositions.