CORNEAL BIOTOLERANCE OF DIFFERENT BIOADHESIVES: COMPARATIVE STUDY

Abstract

Abstract: : Purpose: To study the efficacy and the clinical and histological corneal biotolerance of different bioadhesives Methods:We carried out an "in vitro" study on animal eyes of different bioadhesives with an acrylic or biological base. 150µ lamellar keratectomy was performed with Moria I microkeratome and the corneal lamella was sealed with different bioadhesives. We evaluated effectiveness, speed and hardness of polimerization and corneal transparency. We made an "in vivo" study on Albino New Zealand rabbits (4 eyes per group) evaluating corneal biotolerance (inflammation reaction, neovascularization, opacification) and histological findings. We performed a 5mm intrastromal dissection with Melles spatula and microsclerotome and injected 0.10 mm of the different adhesives: n–butyl cyanoacrylate (Histoacryl®, Tisuacryl®), n–butyl cyanoacrylate ethyl cyanoacetate, n–butyl cyanoacrylate dihexyl maleate and fibrin adhesive (tissucol®) 3 months follow up. Results:The bioadhesives from greatest to least in terms of degree of hardness, speed of polimerization and corneal opacity were: Histoacryl®– n–butyl cyanoacrylate dihexyl maleate – n–butyl cyanoacrylate ethyl cyanoacetate, Tisuacryl®– tissucol®. Efficacy: All were effective except fibrin adhesive. Inflammatory reaction: Severe: Histoacryl® and n–butyl cyanoacrylate dihexyl maleate and n–butyl cyanoacrylate ethyl cyanoacetate. Mild: Tisuacryl® and Minimal/no reaction: fibrin adhesives. Histological findings: Presence of edema, fibroblast activation, new vessel formation and remains of bioadhesives. Conclusions:Acrylic bioadhesives can be an effective alternative to sutures for corneal lamellar sealing. Corneal opacification may be produced by different compounds of the bioadhesive mixture. We need more experimental studies to determine the bioadhesive that can substitute traditional sutures in lamellar keratoplasty.

Keywords: ocular irritancy/toxicity testing • inflammation • anterior segment