Ocular abnormalities in a herd of Old Kladruber Horses: A cross‐sectional study

Abstract

Objective To screen a closed herd of the Old Kladruber Horses (OKH) for the prevalence of ocular disorders and report normal ocular variations. Animals studied Two hundred and sixty‐one horses, 122 Old Kladruber Gray Horses, and 139 Old Kladruber Black Horses owned by the National Stud Farm Kladruby nad Labem, Czech Republic, were included in the study with signalment and pedigree information recorded. Procedures Bilateral ocular examination of manually restrained horses was performed in a darkened environment by a single examiner (RA), using a portable slit‐lamp biomicroscope, direct ophthalmoscope, and monocular indirect ophthalmoscopy using a Finnoff transilluminator and 20 D condensing lens. Fluorescein testing was performed when indicated. Results The animal ages ranged from 3 months to 27 years (mean 7.82 years, median 6 years). The gender ratio (males:females) was 109:152. Ophthalmological abnormalities were found in 133 (50.96%) horses; with right and left eyes affected equally. The most common abnormalities were cataract formation (35 horses), iris hyperpigmentation (29 horses), alterations in corpora nigra size (26 horses), nonsenile vitreal degeneration (24 horses), linear keratopathy (11 horses), corneal stromal haze (nine horses) and corneal subepithelial punctate opacities (nine horses). The most frequent variations of normal ocular anatomy were posterior lenticular suture lines (222 horses), tapetal hypoplasia (95 horses) resulting in a multi‐colored tapetal fundus (31 horses), nuclear sclerosis (48 horses), and senile vitreal degeneration (30 horses). Conclusions Ocular disorders were relatively common in OKH, but typically not vision threatening and not interfering with the quality of life.

Ophthalmic findings in a herd of Caspian miniature horses

“…Visual acuity is essential in prey animals such as horses, primarily as a part of their defence mechanism. Diseases and disorders of the eye can also affect horses’ visual acuity, which may have a negative influence on the horses’ behaviour and performance in sports (Andrysikova et al, 2018).…”

“…Previously, a number of different equine breeds have been evaluated for ophthalmological disorders, including old Kladruber horses (Andrysikova et al, 2018), Thoroughbreds (Hurn & Turner, 2006), Lipizzaner (Rushton et al, 2013), Exmoor (Pinard & Basrur, 2011), Morgan horses (Beech et al, 1984), Rocky mountain horses (Ramsey et al, 1999), American miniature horses (Plummer et al, 2003; Plummer & Ramsey, 2011) and Kentucky mountain horses (Grahn et al, 2008).…”

“…In American miniature horses, various ophthalmic abnormalities have been reported, such as persistent pupillary membrane, cystic lesions of ciliary bodies, retinal dysplasia, cataract and multiple ocular abnormalities (Plummer & Ramsey, 2011). In old Kladruber horses, the most common ocular abnormalities were cataract formation, iris hyperpigmentation and change in corpora nigra size (Andrysikova et al, 2018). Thoroughbred horses have been reported to have cataract formation and peripapillary butterfly inactive lesions as threatening visual deficits (Hurn & Turner, 2006).…”