Clinical evaluation of topical tacrolimus ointment usage in different stages of keratoconjunctivitis sicca in dogs

Christina John,Chelladurai Sowbharenya,Aswathy Gopinathan,Kiranjeet Singh,Pallvi Sharma,Sherin B Sarangom

doi:10.3906/vet-1801-1

Abstract

This study was conducted to investigate the effect of topical tacrolimus (0.1%) ointment in stimulating tear production in dogs with keratoconjunctivitis sicca (KCS). Thirty-six dogs (58 eyes) diagnosed with KCS were included in this study. KCS was grouped as early (E, n = 21 eyes), late (L, n = 21 eyes), and reflex tear due to corneal ulceration (R, n = 16 eyes) based on Schirmer tear test (STT) readings. The dogs in each group were randomly allotted treatment with either tacrolimus 0.1% ointment applied once daily (ET, n = 11 eyes; LT, n = 10 eyes; RT, n = 6 eyes) or cyclosporine (CsA) 0.05% eye drops instilled five times daily (EC, n = 10 eyes; LC, n = 11 eyes; RC, n = 10 eyes) for 2 months. The efficacy of the treatments was evaluated and comparison was made based on complete ophthalmic examination and a scoring system for various parameters like menace reflex, palpebral reflex, pupillary light reflex, conjunctival hyperemia, ocular discharge, corneal clarity, corneal ulceration, corneal vessel length, corneal vessel density, corneal pigmentation area, corneal pigmentation density, STT readings, fluorescein dye test, and Rose Bengal dye test. The effect of treatment was evaluated on day 15, 30, and 60 after treatments. Good quality digital photographs from a fixed distance were taken at each interval to aid subjective evaluation. Data were analyzed using one-way and repeated-measures ANOVA followed by Tukey?s HSD test, Wilcoxon signed rank test, and Kruskal?Wallis test followed by Dunn?s test to identify significant interactions. The level of significance was set to P < 0.05. Improvement in menace reflex and pupillary light reflex was observed in both treatment groups. Conjunctival hyperemia and ocular discharge decreased significantly after treatment with both of the drugs. There was no significant difference in improvement in tear production between treatment groups but tacrolimus 0.1% ointment significantly arrested the progression of pigments. The study concluded that both tacrolimus 0.1% ointment and CsA 0.05% eye drops improve tear production in KCS-affected dogs. Topical tacrolimus 0.1% ointment effectively arrests the progression of pigmentation compared to CsA 0.05% eye drops in KCS-affected dogs.

Highlights

Keratoconjunctivitis sicca (KCS), or dry eye, is a local immune-mediated disease that leads to the deficiency of precorneal tear film, which is crucial for preserving ocular surface health [1,2]
The results of this study support the use of both cyclosporine A (CsA) 0.05% eye drops, instilled five times daily, and tacrolimus 0.1% ointment, applied once daily, for improving tear production in dogs affected with KCS and to reduce the deteriorating clinical signs associated with KCS
For arresting the progression of corneal pigmentation associated with KCS, tacrolimus 0.1% ointment was more effective than CsA 0.05% eye drops

Summary

Introduction

Keratoconjunctivitis sicca (KCS), or dry eye, is a local immune-mediated disease that leads to the deficiency of precorneal tear film, which is crucial for preserving ocular surface health [1,2]. CsA is the most commonly used lacrimostimulant for dogs with KCS either in the form of ointment (0.2%) or as an oil-based suspension (1%–2%). It has unique noncytotoxic effects on T cells at therapeutic concentrations and acts by inhibiting T-cell proliferation, allows regeneration of lacrimal glands and acini, and supports the secretory function [10]. CsA has antiinflammatory properties on ocular tissues, prevents lacrimal gland apoptosis, and has a proliferative effect on

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Conclusion