Congenital ocular abnormalities of Rocky Mountain Horses

Objective: To determine the incidence and describe ocular abnormalities in a cross‐section of the population of Rocky Mountain Horses. Design: Prospective study. Animals: Five‐hundred and fourteen Rocky Mountain Horses. Procedure: Ophthalmic examinations were performed using a slit‐lamp biomicroscop...

Full description

Saved in:
Bibliographic Details
Published in:Veterinary ophthalmology 1999-03, Vol.2 (1), p.47-59
Main Authors: Ramsey, D.T, Ewart, S.L, Render, J.A, Cook, C.S, Latimer, C.A
Format: Article
Language:English
Subjects:
anterior megalophthalmos
cataract
clinical examination
congenital
congenital abnormalities
cornea
cysts
eye
eye diseases
eyes
frequency
histology
horse
horses
incidence
measurement
megalocornea
miosis
partial albinism
population
pressure
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Objective: To determine the incidence and describe ocular abnormalities in a cross‐section of the population of Rocky Mountain Horses. Design: Prospective study. Animals: Five‐hundred and fourteen Rocky Mountain Horses. Procedure: Ophthalmic examinations were performed using a slit‐lamp biomicroscope and an indirect ophthalmoscope. Intraocular pressures were measured by applanation tonometry. Eyes from six horses were obtained for histologic examination. Results: Cysts of the posterior iris, ciliary body, and peripheral retina were detected most frequently (249 horses), and were always located temporally. Curvilinear streaks of retinal pigmented epithelium extending from the peripheral temporal retina marked the boundary of previous retinal detachment in 189 horses. Retinal dysplasia was detected in 125 horses. Multiple ocular anomalies were evident in 71 horses and were always bilateral and symmetrical. Affected eyes had a large, clear cornea that protruded excessively and had an apparent short radius of curvature, a deep anterior chamber, miotic and dyscoric pupil, and iris hypoplasia. Pupillary light responses were decreased or absent and pupils failed to dilate after repeated instillation of mydriatic drugs in horses with multiple ocular anomalies. Less frequently encountered abnormalities included peripheral iridocorneal adhesions and goniosynechiae. Congenital cataract was always present in eyes with multiple abnormalities. Intraocular pressures did not differ among horses with normal eyes and horses with multiple ocular abnormalities. Histologic examination of eyes corroborated the clinical appearance.
ISSN:1463-5216
1463-5224
DOI:10.1046/j.1463-5224.1999.00050.x