Effects of topical ketorolac tromethamine on tear parameters, meibography, goblet cell density, and conjunctival oxidative stress in healthy dogs

Objectives The objective of the study was to evaluate whether a twice‐daily instillation of 0.45% preservative‐free ketorolac tromethamine (FKT) or 0.4% benzalkonium chloride‐preserved ketorolac tromethamine (BACKT), every 12 h for 30 days may affect tear film parameters and the meibography in healthy dogs. Additionally, we assessed whether the same treatments irritated the ocular surface, affected goblet cell density (GCD), and the levels of oxidative stress biomarkers (OSB) in the conjunctiva of the same dogs. Procedures Experimental and masked comparison study. In 11 healthy dogs baseline values of the lipid layer thickness, tear meniscus height, non‐invasive tear breakup time (NI‐TFBT), and the meibomian gland (MG) loss were assessed by OSAvet®. For each dog, one eye received 40 μL of BACKT, while the other received 40 μL FKT, every 12 h for 30 consecutive days. Tear parameters and meibography were repeated 15, 30, and 60 days post‐treatments. Conjunctival hyperemia and blepharospasm were monitored at the same time points. At baseline and Day 30, a conjunctival biopsy was collected for GCD and OSB determination. Results Conjunctival hyperemia and blepharospasm were not observed. At Day 15, the MG loss increased only in FKT‐treated eyes (p