Retinal Disease - Donkey

Blindness due to retinal disease

Due to the non-athletic nature of the donkey, early retinal disease is usually missed and it is not until significant damage has occurred that the loss of vision is noticed and the donkey is presented for examination.

Clinical Signs

Detailed ophthalmoscopic examination is required. Often the pupil is fully dilated already, as pupillary light responses are poor or absent.

During ophthalmological examination, look for:

• Pale optic nerve
• Depigmentation in the non-tapetum
• Blood vessel thinning
• Hyper-reflectivity of the tapetum
• Atrophy and decreased vascular supply to the optic disc

Differential diagnoses

1. Retinal detachment, usually caused by inflammation or trauma
2. Equine recurrent uveitis
3. Chorioretinitis, discrete lesions in the nontapetal zone
4. Optic nerve disease, unilateral or bilateral. Pupil is dilated with no pupillary light reflex (PLR). Untreatable.

Treatment

Retinal disease with visual deficits carries a guarded prognosis. The only treatment is the use of anti-inflammatories if an inflammatory aetiology is suspected. Tests for systemic disease are indicated in such cases.

References

• Grove, V. (2008) Conditions of the eye In Svendsen, E.D., Duncan, J. and Hadrill, D. (2008) The Professional Handbook of the Donkey, 4th edition, Whittet Books, Chapter 11

EYE DISORDERS - DONKEY

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