ABSTRACT
Chronic topical glaucoma therapy was reported to cause deleterious changes to the ocular surface epithelial layer. The aim of this study was to compare the histological changes in the cornea after chronic exposure to latanoprost preserved with 0.02% benzalkonium chloride [BAK] eye drops, travoprost preserved with sofZia eye drops and preservative-free artificial tears. Fifteen white rabbits were randomized into three groups [five animals each]. They received once-daily topical application of one of the three treatments for 30 days. The first group [the control group] received preservative-free artificial tears [Refresh Plus]. The second group received travoprost preserved with SofZia [Travatan Z]. The third group received latanoprost preserved with 0.02% BAK [Xalatan]. Enucleation was performed at the end of the experiment. Corneal samples were processed for light and transmission electron microscopic studies and conjunctival samples for light microscopic study. The mean epithelial height of the corneal epithelium, the mean number of goblet cells in the conjuctival epithelium and the mean area% of PAS-positive goblet cells were measured using an image analyzer. These results were statistically analysed using analysis of variance and the Hest. Latanoprost eye drops preserved in BAK produced toxic changes in the form of degeneration and desquamation of the superficial epithelial cells in the cornea, separation of Descemet's membrane and degeneration of endothelial cells, in addition to decreased number of goblet cells in the conjunctiva. Travoprost eye drops preserved in sofZia were safer and produced slight changes on the rabbit's ocular surface compared with latanoprost eye drops preserved in BAK. It was concluded that antiglaucomatous drugs preserved with sofZia produced less corneal and conjunctival changes than those preserved with BAK