Treating Evaporative Dry Eye Disease in Dogs Based Upon Tear Film Lipid-Layer Thickness: A Retrospective Cohort Study.

Abstract

OBJECTIVE: To classify evaporative dry eye disease (EDED) in dogs and trial therapies based upon tear film lipid layer thickness. ANIMALS: Twenty client-owned dogs diagnosed with EDED. PROCEDURES: Patients were recruited for retrospective assessment if they were diagnosed with EDED in the absence of other diagnoses that may lead to tear film instability. Tear film interferometry was performed to diagnose a lipid-deficient EDED (LD-EDED; <&#x2009;30&#x2009;nm) or idiopathic EDED (I-EDED; >&#x2009;30&#x2009;nm). Dogs with LD-EDED were treated with combined topical paraffin and wool fat ointment and oral flaxseed oil. Dogs with I-EDED were treated with combined topical trehalose and hyaluronic acid drops and either topical compounded tacrolimus or cyclosporine. A TFBUT was performed a minimum of 4&#x2009;weeks later, and these were compared pre- and posttreatment via paired student t-tests and linear regression analysis with Pearson's correlations. RESULTS: Patients with LD-EDED had a significant and strong correlation between pretreatment lipid layer thickness and pretreatment TFBUT (p&#x2009;=&#x2009;0.037). Total mean pre- and posttreatment TFBUT was 3.63&#x2009;&#xb1;&#x2009;2.48 and 10.79&#x2009;&#xb1;&#x2009;4.83&#x2009;s (p&#x2009;<&#x2009;0.001) seconds, respectively (p&#x2009;<&#x2009;0.001). LD-EDED pre- and posttreatment TFBUT was 3.75&#x2009;&#xb1;&#x2009;3.05&#x2009;s and 11.75&#x2009;&#xb1;&#x2009;3.98&#x2009;s (p&#x2009;<&#x2009;0.001), respectively (p&#x2009;<&#x2009;0.001). Patients with I-EDED had a pre- and posttreatment TFBUT of 3.56&#x2009;&#xb1;&#x2009;2.63&#x2009;s and 9.76&#x2009;&#xb1;&#x2009;4.32&#x2009;s, respectively (p&#x2009;<&#x2009;0.001). CONCLUSION: Dogs with EDED appear to have significantly longer TFBUT following directed therapy.