Unlike with a human, they can't understand what is happening and have a sit down talk about how to cope.
They have to do it themselves but as their owners, there are things we can do to help.
The first and most important is find out the cause of the blindness in case treatment is needed.
Causes Different causes have a different impact on a cat's vision - some lead to a gradual loss of sight, in which case the cats can often adapt as time goes by.
But others cause a rapid loss of sight and this leads to total disorientation and fear in the car.
Optic neuritis is a condition where the optic nerve becomes inflamed and no longer functions properly.
This is the nerve responsible for carrying the visual information collected by the eyes to the brain to be interpreted and if it no longer works, neither does the vision.
Thankfully, this is a rare condition in cats.
Hypertension or high blood pressure is a major disease in cats and is one of the top causes of acute onset blindness, where the vision is lost totally and quickly.
High blood pressure can cause damage to the small blood vessel in the back of the eye that then leads to bleeding or to fluid leaking from them.
This has the effect of causing the retina to become detached - this is the layer of light sensitive cells that are found lining the back of the eye and let us see things.
If the retina is detached, then it stops working and blindness occurs.
High blood pressure can also cause bleeding in the front of the eye, which can be seen from a casual inspection.
Sometimes the problem comes not from the eye but in the brain and some diseases of the brain such as infections, inflammation or tumours can mean that those signals sent from the optic nerve are no longer processed.
Finally, cats can suffer with degeneration of the layer of light sensitive cells at the back of the eye or the retina.
When this happens, it tends to be a slow process so cats can often adapt to their reducing vision.
Occasionally, however, it can be a sudden onset case that robs them of their sight very quickly.
Diagnosis A trip to the vets is essential if you think your cat is losing its sight so that they can assess what the problem is and what can be done.
There are a number of tests that a vet may use to diagnose the problem and help find a course of treatment if there is one.
These can include: - Examination of the eye with an ophthalmoscope - Blood pressure measurement to see if high blood pressure is the cause or part of the problem.
This is done much the same way as with humans by wrapping a special cuff around a leg to monitor the blood flow - Blood and urine tests may be used to see if there are any underlying medical conditions such as kidney disease.
- Brain scans may be needed if the cause of the problem could be with the brain rather than the eyes.
Treatment will depend on what the cause of the condition is but can often be medication.
In some cases, there may be nothing that can be done to cure the problem and the cat will need help to learn to adjust to their new lack of sight.
Caring for a blind cat Blindness doesn't mean they have to be euthanized because cats can adapt to a loss of sight.
They make use of their other senses including their sense of touch with their whiskers to stop them walking into objects and their smell and hearing are both very acute anyway.
It may be more distressing for the owner to see the cat walking into things or stumbling until they adapt to their condition.
During this period, it is important to keep everything in the same place so they can adjust to where things are.
Don't move the furniture around and don't alter the position of any of their stuff.
Try to avoid loud noisy approaches to them as this can frighten them.
While blind cats can go outside, it is often best to keep them inside or only allow them out into a small, restricted space for their own safety.