Effects of 5% sodium chloride ophthalmic ointment on thickness and morphology of the normal canine cornea.

Abstract

OBJECTIVE: To determine the effect of 5% sodium chloride ophthalmic ointment (5% NaCl) on thickness and morphology of the normal canine cornea using ultrasonic pachymetry (USP), in&#xa0;vivo confocal microscopy (IVCM), and Fourier-domain optical coherence tomography (FD-OCT). METHODS: Five healthy laboratory Beagles received ophthalmic examinations including USP, IVCM, and FD-OCT prior to and at fixed intervals following treatment. The right and left eyes were treated with 5% NaCl and artificial tears ophthalmic ointment (AT), respectively, every 2&#xa0;hours for 4 treatments/d (days 2-9), and then hourly for 7 treatments/d (day 10). Treatment groups were statistically compared using mixed-effects linear regression. RESULTS: Treatment with 5% NaCl resulted in a 12&#xa0;&#x3bc;m decrease in corneal thickness from baseline (P&#xa0;<&#xa0;.001), while there was no significant difference in corneal thickness between values obtained at baseline and following treatment with AT (P&#xa0;=&#xa0;.82). Epithelial cell density significantly increased from baseline (530&#xa0;&#xb1;&#xa0;52 cells/mm) to 577&#xa0;&#xb1;&#xa0;43 and 567&#xa0;&#xb1;&#xa0;15 cells/mmwith 5% NaCl and AT, respectively (P&#xa0;=&#xa0;.003 and .005, respectively). However, keratocyte cell density in the anterior and posterior stroma and endothelial cell density did not significantly differ following treatment with 5% NaCl or AT ointment (P&#xa0;>&#xa0;.05). CONCLUSIONS: Short-term topical treatment with 5% NaCl decreased corneal thickness in normal dogs with no observable changes in corneal morphology or signs of ocular toxicity.