Cats’ eyes. They allow our beloved four-legged-friends to see well enough to enjoy night-life and hunt. They are also iconic in our society; from the “cat’s eye winged eyeliner” to the useful lights on roads, cats’ eyes are famous! What happens, then, if Felix’s eyes don’t work how they used to? It may seem a scary thought for owners, but cats, especially older cats, can become blind very quickly – we call this ‘sudden onset blindness’. The good news is that cats can go on to enjoy life without vision, and many owners are amazed by how well their feline friends adapt! So, how can you tell if your cat is blind, why would he go blind, and what can we do about it…?

How will I know if my cat is blind?

Signs of blindness will include:

  • Disorientation; you cat may be less keen to go outside, slower walking around the house, and generally more hesitant about moving.
  • Bumping into things; cats have incredible whiskers for feeling, but also rely on their eye- sight. If a cat has sudden-onset blindness, it may take them several weeks to adapt, and may be found bumping into things in the meantime.
  • Changes in the eyes; you may notice your cat’s eyes become very dilated – you may find you now have your very own “Puss-in-Boots” with such big eyes! This is because the retina (the light-sensitive layer at the back of the eyeball) is not processing light, and there will be no signals to the pupil to constrict in the presence of light
  • The vet check; we can assess cats’ abilities to process light, and react to visual changes around them, by a ‘menace response’ and a ‘pupillary light reflex’. Your vet will also want to measure your cat’s blood pressure to check for elevated blood pressure, known as ‘hypertension’, and also a urine sample and blood sample to check kidney function, which we will explain below.

Why would my cat go blind suddenly?

There are a number of reasons, but some of the more common include…

  1. Hypertension. High blood pressure can cause the retina (where the cells which detect light, colour and movement are) to detach from the rest of the eye’s ‘hardwiring’ and blood supply.
  2. Trauma. Any severe damage to the eye or head can cause blindness, either because of direct damage to the eye, or detachment of the retina.
  3. Brain pathology. Cats may take the world around them in with their eyes, but they need the brain to process what they are seeing. Tumours, inflammation and infection can impede the brain’s ability to do this.
  4. Optic neuritis. The optic nerve is located at the back of the eye; this incredible structure sends impulses to the brain to help piece together a picture. If this nerve is damaged or inflamed, it will not be able to relay these messages from the world outside the eye, to the brain. When the optic nerve is inflamed, we call this ‘optic neuritis’.

Optic neuritis is rare in cats; hypertension though is very common in older pets, especially when they have chronic kidney disease. Losing vision, drinking and urinating more, losing weight and lethargy are tell-tale signs of the kidneys not working as they should.

So, your cat is blind… What can we do about it?

  • In some cases, if blindness suddenly appears and there is a clear underlying cause such as hypertension, we can treat the underlying causes. Blood-pressure tablets can regulate the high blood pressure; when the eye is no longer exposed to abnormally high pressures, it is possible that the retina can return to its normal place. However, this is very dependent on how quickly the blindness was noticed, how long the blood pressure has been elevated, the extent of damage to the retina, the general health of the cat and how severe the hypertension is.
  • If vision cannot be restored, trying to keep the cat’s environment as similar as it was prior to blindness will help little Felix find his way around!
  • Cats have exceptional smell, hearing, and whiskers for feeling; many cats adapt well to losing their vision, and continue to live very happy lives into their twilight years!
  • We want our cats to live happy lives, expressing natural behaviours; for many cats, this involves hunting, playing with friends (four-legged and two-legged!), or going to patrol the neighbourhood. Sadly, some of these activities may need modified. For playing with your cat, tactile and smell-based toys can still be very fun for your cat. Letting them outdoors when they are less able to navigate leaves them vulnerable to road traffic accidents and being bullied by other dogs and cats on the streets; ideally, limiting them to a walled-in and familiar garden will be a happy but safe compromise.
  • Ensuring you take your cat for regular health checks will allow you to discuss management as well as noticing any other health problems which may arise.

We wish you the very best with your cat, whether he is able to see or not!

“Cats are connoisseurs of comfort.” – James Herriot