A retinoscopic survey of 333 horses and ponies in the UK
Article first published online: 18 MAR 2014
© 2014 American College of Veterinary Ophthalmologists
Special Issue: Equine Ophthalmology
Volume 17, Issue Supplement s1, pages 90–96, July 2014
How to Cite
Bracun, A., Ellis, A. D. and Hall, C. (2014), A retinoscopic survey of 333 horses and ponies in the UK. Veterinary Ophthalmology, 17: 90–96. doi: 10.1111/vop.12158
- Issue published online: 4 JUL 2014
- Article first published online: 18 MAR 2014
- Nottingham Trent University
- refractive state;
Ophthalmic examination in the horse is generally limited to crude assessment of vision and screening for ocular lesions. The refractive state of equine eyes and the potential impact on vision and performance requires further investigation.
To assess the refractive state of a large, mixed-breed sample of horses and ponies in the United Kingdom (UK).
The refractive state of both eyes of 333 horses and ponies was determined by streak retinoscopy, and the effect of age, height, gender, breed and management regime on the refractive state assessed.
Emmetropia was found in 557 of 666 (83.63%) of eyes; 228/333 (68.5%) of the horses/ponies were emmetropic in both eyes. Refractive errors of greater than 1.50 D (in either direction) were found in 2.7% of the eyes tested. Ametropic eyes included hyperopia (54%) and myopia (46%). Anisometropia was found in 30.3% of horses and ponies. Breed of horse/pony was the only factor that affected refractive state (in the left eye only, P < 0.05) with Thoroughbred crosses having a tendency toward myopia and Warmbloods/Shires toward hyperopia.
Discussion and Conclusion
The retinoscopic survey found emmetropia to be the predominant refractive state of the equine eye with no evidence of an overall trend toward myopia or hyperopia. However, individual and breed-related differences were found. Such factors should be considered in the selection of horses for sport and leisure, and when evaluating their performance potential. More comprehensive visual testing would be valuable in identifying underlying causes of behavioral problems.