Clinical and Experimental Ophthalmology

Biography

Biography: Khalimova Liliya Ilusovna

Abstract

Aim: Collagen cross-linking (CXL) with UV-A irradiation 370 nm and 0.1% riboflavin stabilizes the pathological process in the cornea. Improvement of the Standard UV-A corneal cross-linking resulted in Accelerated and Pulsed-light accelerated UV-A cross-linking. It is necessary to compare these UV cross-linking techniques to assess its efficacy.

Methods: The experiments were carried out on 36 porcine eyes in 4 groups (8 porcine eyes each) ex vivo: 1st group – intact (control); 2nd group – standard UV-A corneal cross-linking (S-CXL) – 3 mW/cm2, 30 min; 3rd group – accelerated UV-A corneal cross-linking (A-CXL) – 18 mW/cm2, 5 min; 4th group – pulsed-light accelerated UV-A corneal cross-linking (Pl-A-CXL) – 18 mW/cm2, 10 min, pulsed exposure (1 sec on / 1 sec off). In all experimental groups Epi-Off, UV-A light 370 nm and 0.1% Riboflavin + 20% Dextran was used. The flaps from the cornea were stretched until they were completely ruptured using a universal tensile testing machine. Biomechanical properties were assessed by the force at rupture and the Young's modulus. 

Results: All investigated methods of UV-A cross-linking led to an increase in the force at rupture and the Young's modulus of the porcine corneas. Young's modulus increased: S-CXL by 98 ± 12,1%, A-CXL – 86 ± 9,4% and Pl-A-CXL – 89 ± 10,2%. Ultimate tensile strength increased: S-CXL by 67.8 ± 9.5%, A-CXL - 55.3 ± 7.2%, Pl-A-CXL - 58 ± 8.1%. The maximum results of biomechanical strength were obtained in the S-CXL group. However, statistically significant difference between Standard, Accelerated and Pulsed-light accelerated UV-A corneal cross-linking was not obtained.

Conclusions: Standard, Accelerated and Pulsed-light accelerated UV-A corneal cross-linking increased the biomechanical properties of porcine corneas ex vivo and Young's modulus. Standard UV-A corneal cross-linking had slight advantage.