Blindness in Horses
Key takeaways
Blindness in horses is uncommon, and often difficult to identify due to their ability to adjust to gradual vision loss. - Some horses may seclude themselves from the herd, or become more spooky or flighty
- Vision loss can occur in one eye or both, and is caused by a wide variety of ocular conditions including infections, injuries, cancers, and cataracts
- Horses showing signs of sudden vision loss or damage to the eye require emergency medical attention in order to prevent permanent vision loss
- Diagnostics include a physical examination, ocular examinations, diagnostic imaging, and bloodwork
- Treatment varies depending on underlying conditions, and may include medication and surgery
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A closer look: Blindness in Horses
The severity of blindness primarily depends on whether there is reduced or complete loss of vision. Horses with reduced vision may have increased startle responses, as they may see shadows or shapes that are confusing and frightening. Horses with no vision are typically startled by sudden noises or contact with their body, rather than visual cues.
Vision loss can occur quickly (acute) or gradually (chronic). Chronic vision loss may be asymptomatic, as horses typically adjust to changes in vision. Acute blindness may present as increased startle responses, or a lack of spatial awareness. Some horses with vision loss may seclude themselves from herd mates to avoid becoming injured.
Blindness can affect both eyes (bilateral) or one eye (unilateral).
Any sudden onset of vision loss should be treated as a medical emergency. Doing so provides the best chance of preserving vision. It is important to note preserving vision may not always be possible even with emergency intervention.
Possible causes
Risk factors
Vision loss is uncommon in horses, although some conditions which may result in vision loss, such as cataracts, are more common in older horses. Most conditions causing vision loss are due to damage to the eye, either through traumatic injury or inflammation.
Conditions leading to blindness are often painful, and vision loss can be highly stressful, especially if blindness develops suddenly.
Horses benefit from prompt veterinary attention if vision loss is suspected. Reddened, irritated, discolored, or painful eyes require emergency intervention to have the best chance of protecting vision.
Testing and diagnosis
Diagnostics include:
- A physical examination
- Ocular examination
- Bloodwork
- Diagnostic imaging, including X-rays of the skull
- Neurologic examination
Treatment is determined by the underlying condition, and may include:
- Surgery, including removal of the affected eye
- Laser eye surgery
- Medication, such as antibiotics and anti-inflammatories
- Chemotherapy
Horses can still have a good quality of life with vision loss, however they may require lifestyle changes to do so. They often struggle in herds, and with changing environments. Slow and careful introduction to new environments may help blind horses adjust to their new space. The environment itself may require changes, such as removing trees and debris in the fields, and replacing fencing with smooth wire to prevent injury. Training methods may require adjustment away from visual cues towards auditory or pressure cues.
Similar symptoms
Horses that are naturally more flighty or easily startled may be mistaken for having loss of vision or blindness. Thorough examination by a veterinarian can rule out underlying vision issues in these horses.
