Animals
This study was conducted on 20 healthy horses with different breeds including Koninklijk Warmbloed Paardenstamboek Nederland (KWPN), crossbreed, thoroughbred, and Friesian from different breeding centers located in Tehran province. Horses under study had neither clinical signs nor a history of eye disorders. No evidence of ocular inflammation or infection was observed during ophthalmic examinations conducted by a veterinarian. Examinations consisted of menace test and assessment of both eyeballs’ location, size of both eyes, motility of both eyes, and the existence of any ocular discharge. No history of antimicrobials or antifungal drugs administration in 2 weeks before specimen collection was also confirmed. Horses were divided into three different age intervals including 1-5 years old, 5-10 years old, and older than 10 years old. Characteristics of animals are shown in Table 1.