Topical Application of Preserved and Unpreserved Bevacizumab Eye Drops Improves Ocular Surface Parameters in Dogs with Chronic Keratitis: A Pilot Study

Corneal neovascularization (CNV) in dogs causes chronic ocular surface inflammation, which may disrupt tear film stability and meibomian gland function. As bevacizumab inhibits abnormal vessel growth and affects tear composition, it may benefit dogs with ocular surface disorders. The aim of this pilot study was to evaluate the effects of bevacizumab eye drops on the ocular surface in dogs with chronic CNV. Fourteen eyes from nine client-owned dogs were included. Dogs received either preserved (BBAC-group) or unpreserved (B-group) 0.25% bevacizumab eye drops twice daily for 28 days. Re-examinations occurred one week after treatment initiation, at the end of treatment, and three months later. An ocular surface analyzer was used to assess tear composition and meibomian glands via interferometry, tear meniscus height, and meibography. Ocular and systemic toxicities were monitored, and clinical signs were scored. Serum VEGF levels were measured via ELISA before and after treatment. No statistically significant changes in intraocular pressure, tear production, or systemic VEGF levels were observed. Statistically significant improvements were noted in conjunctival hyperemia and chemosis in both groups, ocular discharge in the BBAC-group, and fluorescein uptake in the B-group. Both formulations were safe and well tolerated. These preliminary findings suggest that topical bevacizumab may have potential benefits for CNV and ocular surface disorders in dogs, although larger studies are needed.

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