Abstract
Purpose: :
Aim of this animal experiment was the examination of the biomechanical effect of a modified method, which suggests leaving the epithelium intact and applying Benzalkonium chloride (BAC) on rabbits' corneas.
Methods: :
32 eyes of 16 rabbits were divided in 4 groups. Group 1 was treated with intact epithelium and without BAC. Also in group 2 and 3 the epithelium was left intact and a solution of riboflavin that contained BAC 0.02 % and 0.04 % was used. Group 4 was treated according to the standard protocol with mechanical debridement of the epithelium. After the treatment of both eyes, the rabbits were euthanized to prepare the corneas in order to determine the riboflavin absorption coefficient and their biomechanical properties.
Results: :
The absorption coefficients of group 2, 3 and 4 were significantly increased compared to group 1 and without significant differences between group 2, 3 and 4. Stress-strain-values and Young`s modulus of group 2, 3 and 4 were significantly increased compared to group 1. The stiffening effects did not differ within group 2, 3 and 4. The resistance to enzymatic digestion was significantly increased in group 2, 3 and 4 compared to group 1.
Conclusions: :
Adding BAC 0.02 % causes a sufficient epithelial permeability for riboflavin, which enables its stromal diffusion and results in increased corneal stiffening after cross-linking comparable to the standard protocol. Further safety studies are indispensable before clinical use.
Keywords: cornea: basic science • keratoconus