Impression cytology of the healthy equine ocular surface: Inter-observer agreement, filter preservation over time and comparison with the cytobrush technique.

Background: The cytobrush technique is commonly used to sample the equine ocular surface. Impression cytology (IC) is an innovative noninvasive method, which allows for the collection of superficial layers of ocular epithelium.

Objectives: The aims of this study were to compare the cytobrush and IC techniques on healthy equine ocular surfaces, to assess the agreement between observers with different levels of expertise, and to test the preservability of filters over time.