A survey of ocular pathology in Warmblood horses in South Africa

Abstract Background Warmblood horses are a popular breed around the world for equestrian sports. Previous studies have investigated ocular findings in other breeds of horses; however, no studies exist for the Warmblood breed. Objectives To determine the prevalence of ocular abnormalities in a convenience sample of Warmblood horses in South Africa and to determine if the prevalence of lens and chorioretinal lesions increase with age. Study design Descriptive, observational study. Methods Warmblood horses underwent a full ophthalmic examination which included a Schirmer tear test (STT), tonometry, fluorescein dye testing, slit lamp biomicroscopy and indirect ophthalmoscopy. Age was categorised into three groups namely <8 years old, 8–13 years old and 14+ years old for statistical analysis. Prevalence of lens and chorioretinal lesions were compared between age categories. Results One hundred and four horses (208 eyes) were examined. The age range was 5 months to 30 years (mean 11 years, standard deviation [SD] 6 years). Ocular pathology was noted in 125 eyes (60.1%) and 79 horses (76%). The highest number of lesions were noted in the choroid and retina, iris and lens. Chorioretinal lesions were seen in 100 eyes (48.1%) and in 65 horses (62.5%). Iridial lesions were seen in 19 eyes (9.1%) and 12 horses (11.5%). Cataracts were seen in 19 eyes (9.1%) and in 13 horses (12.5%). The presence of total chorioretinal lesions (eye level [ p  = 0.002]; horse level [ p  = 0.004]), focal chorioretinal lesions (eye level [ p  = 0.004]; horse level [ p  = 0.008]) and cataract (eye [ p  = 0.03]; horse level [ p  = 0.02]) were all shown to statistically increase with age. Main limitations A small sample size and limited geographic area. Conclusions There was a high prevalence of ocular pathology in this population of Warmblood horses in South Africa. This reiterates the importance of an ocular examination as a part of routine health checks, as well as during prepurchase examinations.