As they age, animals can experience a decline in their eyesight, but occasionally, some animals lose their vision altogether.
This can be particularly distressing for the animal and owner if it occurs suddenly, as animals do not have time to adapt.
Sudden, total vision loss is not typical of ageing and often indicates underlying disease that needs treatment.
Animals that become blind suddenly may exhibit obvious behavioural changes, and appear disoriented.
There are many causes of blindness.
These include diseases that affect the surface of the eye (like dry-eye), the front chamber of the eye (like cataracts), the retina (like glaucoma or retinal detachment), the optic nerves (like infection or inflammation), and those impacting the brain (like stroke or organ failure).
Blindness can also occur secondary to ingestion of toxins (for example, an overdose of ivermectin) or certain cancers (particularly eye and brain tumours).
Some conditions, such as diabetes, predispose animals to developing cataracts.
If you suspect that your pet has gone blind, it is important to seek veterinary attention as soon as possible.
It is useful for your veterinarian to know whether you have observed a change in the appearance of the eyes, any changes in the overall health of your pet, and any recent medications they have been on, as well as any changes you have noted in their behaviour.
Your veterinarian will conduct a physical examination and may perform additional tests, such as blood tests and blood pressure measurement.
Your pet may be referred to a veterinary ophthalmologist for further evaluation and treatment.
In some cases, blindness can be reversed with treatment.
For example, it is possible for detached retinas to be surgically reattached. Similarly, cataracts may be removed.
My late dog Phil was almost entirely blind when cataract surgery restored his vision.
Interestingly, the first thing he did with his brand new eyes was walk up to the cat's food bowl and pee in it, as if he had been waiting for the opportunity to do so for some time.
Because some conditions must be treated in a narrow window of time to ensure vision can be restored, it is important to see your veterinarian early if you suspect that your pet's vision has deteriorated.
Dogs and cats can adapt well to loss of vision over time, with most able to successfully navigate their way around their home.
If you do live with a blind or vision-impaired dog or cat, there are a number of steps that you can take to make life easier for them:
BIONDI, V., PUGLIESE, M., VOSLAROVA, E., LANDI, A. & PASSANTINO, A. 2022. Animal Welfare Considerations and Ethical Dilemmas Inherent in the Euthanasia of Blind Canine Patients. Animals, 12. DOI: 10.3390/ani12070913
Dr Anne Quain BVSc (Hons), MANZCVS (Animal Welfare), Dip ECAWBM (AWSEL) is a lecturer at the Sydney School of Veterinary Science and a practising veterinarian.
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