RIBOFLAVIN FILM IN UV CORNEAL CROSS-LINKING. EX VIVO STUDY

Abstract

The article presents information on the effect of precorneal film of Riboflavin on the degree of UV absorption of the cornea in the process of performing UV cross-linking experiment. Model of UV crosslinking (370 nm, 3 mW/cm2) was reproduced on porcine corneas with the use of drugs of 0.1% Riboflavin for saturation: in the 1st group, the isosmotic solution, 2nd - 20% dextran, 3- rd - 1.0% hydroxypropyl methylcellulose (HPMC). Variation in the readings of the UV absorption of the system «cornea - Riboflavin - precorneal film and cornea - Riboflavin» was registered by the device «UV tester». It is established that the cornea, treated with isosmotic solution of Riboflavin or a solution of Riboflavin with HPMC had the most pronounced UV-absorbing effect due to the active penetration of the photosensitizer into the stroma. Herewith, viscous solutions, having in its composition HPMC or dextran, implemented its protective effect by sustainable precorneal riboflavin film. The decrease in corneal thickness due to the dehydrating action of dextran contributed to the decline of light-absorbing properties of the cornea, which was offset by stable film formed by Riboflavin and dextran. Isosmotic solution of Riboflavin forms an unstable surface layer of the photosensitizer that require more frequent instillation.