Tear ferning test in horses and its correlation with ocular surface evaluation

Area of Science:

• Veterinary Ophthalmology
• Ocular Surface Diagnostics
• Equine Health

Background:

• The ocular surface health in horses is crucial for their well-being and performance.
• Evaluating tear film stability and ocular surface integrity is essential for diagnosing and managing eye conditions.
• The tear ferning test (TFT) is a cytological method that analyzes tear crystallization patterns.

Purpose of the Study:

• To describe the tear ferning test (TFT) in healthy horses.
• To correlate TFT results with other ocular surface parameters.
• To establish TFT as a potential diagnostic method in equine ophthalmology.

Main Methods:

• Tear samples were collected from 60 eyes of 30 healthy horses.
• Tear crystallization patterns were classified using Rolando's method.
• The STEPanizer(©) stereology tool was used for quantitative analysis of crystallization.
• Conjunctival biopsies were performed for further evaluation.

Main Results:

• TFT classified as Type I (30%), Type II (51.7%), and Type III (18.3%).
• Quantitative analysis showed distinct point counts for each ferning type.
• No significant correlation was found between right and left eyes or other evaluated factors.
• Conjunctival biopsies revealed goblet cells and inflammatory cells (lymphocytes, plasmocytes, eosinophils).

Conclusions:

• The tear ferning test (TFT) is a safe and easily performable diagnostic method for horses.
• Standardization of TFT, with or without the STEPanizer(©) tool, provides an additional approach for evaluating the equine ocular surface.
• TFT can aid in the early detection and management of ocular surface diseases in horses.