Purpose: The aim of this study was to compare the effect of topical olopatadine, epinastine, and lubricant eye drops on dry eye ocular surface disease in the botulinum toxin B (BTX-B)-induced mouse model of keratoconjunctivitis sicca.
Methods: CBA/J mice were randomized into 3 experimental groups of 10 animals each. All mice received a transconjunctival injection of 0.05 mL of 20-mU BTX-B solutions into the left lacrimal gland. Three (3) days after intralacrimal gland injections, each group received treatment with twice-daily topical lubricant as a control, 0.1% olopatadine, or 0.05% epinastine eye drops. To monitor the progression of dry eye tear production, an ocular surface fluorescein staining score was evaluated in each of the 3 experimental groups.
Results: Three (3) days after the intralacrimal gland injection of BTX-B, aqueous tear production was significantly decreased (1.95+/-0.64 mm), compared to baseline level (2.69+/-0.66 mm; P<0.001). Similarly, there was a statistically significant increase in the proportion of mice with a corneal staining score of 2 or greater at 3 days postinjection, compared to the preinjection value (P<0.001). There were no statistically significant differences in aqueous tear production between the 3 different medication groups at all time points. Aqueous tear production in neither the olopatadine nor the epinastine-challenged groups was further decreased compared to the lubricant-treated group. Difference in the proportion of mice with a low- and high corneal staining score between the control and study groups did not reach statistical significance throughout the 4-week experimental period. In addition, changes in corneal fluorescein staining of the olopatadine group versus the epinastine group did not show a statistically significant difference.
Conclusions: Topical olopatadine and epinastine do not cause significantly additional damage to the compromised ocular surface secondary to dry eye after continuous 4-week, twice-daily application. Topical olopatadine and epinastine appear to have comparable effects on aqueous tear-production and corneal-surface changes in this mouse model.