CORNEAL CROSS-LINKING BEFORE INTRASTROMAL RING SEGMENT IMPLANTATION DECREASES THE EFFECTIVENESS OF THE RINGS

Abstract

Purpose : To compare the clinical and histological response after intracorneal ring segment (ICRS) implantation with previous and posterior corneal crosslinking (CXL) in an experimental animal model (hen).

Methods : We performed surgery for this study on 16 hens (32 eyes) which were randomly divided into three groups. In the first group , epi-off CXL was performed before ICRS implantation by a manual Technique (Ferrara Technique).In the second group implantation of ICRS was performed before epi-off collagen CXL. After ICRS implantation, hens were followed clinically for 4 months, when they were euthanized for histological analysis and immunofluorescency studies. Quantitative measurements of the histological preparations were also performed. Direct transmittance of the central cornea was also measured in each group. Values of the measured variables were analyzed by calculating the mean and standard deviation. SPSS 19 Statistical software was used. An independent T Student Test was used for comparisons between the two groups. A p value less than 0.05 was considered to be statistically significant.

Results : In the first group 83% of the eyes had good clinical follow up. Complications described were, superficial neovascularization and intrasurgically segment break . In the second group 71% had good follow up and complications were ;neovascularization and spontaneous extrusion. Clinically, in both groups fewer deposits were found with lower intensity than in ICRS implantation without CXL. Histologically, statistically significant differences were found in corneal thickness and segment rotation. All these values were lower in the first group. Direct transmittance in both groups 4 months after treatment was similar to no treated corneas.

Conclusions : Cross linking in combination with ICRS implantation in an experimental animal model is related to some complications that must be considered in daily practice. Corneal crosslinking before implantation of ICRS leads to less clinical and histopathological wound healing response than cross linking after implantation.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.