IT WAS 70 years ago last month since reflectors called ‘cats’ eyes’ were first used on our roads to help drivers see in the dark. They were aptly named and designed in honour of our feline friends by inventor, Percy Shaw, after the reflection from a pair of real cat’s eyes prevented him from crashing his car in dense fog.

Many people will have seen the glimmer of a pair of cat’s eyes at night peeking out from behind a tree or bush, but what causes this and what else is special about a real cat’s eyes?


Cat vision:
Cats’ eyes are similar to ours in that they have a cornea, pupil, lens and iris. However, their eyes are far stronger and catch 50 per cent more light than a human eye and are eight times more sensitive at night.

Although a cat’s general vision may be somewhat blurred in comparison to ours, they can detect the slightest movement. They also have excellent depth perception, which means they can usually judge distance much better than most humans.

Many people wonder if cats can see in colour. It is thought that they can differentiate between shades and hues, though not necessarily distinguish different colours.

The reflective nature of their eyes is the result of tapetum lucidum, a reflective layer at the back of the eye that enhances an animal’s vision in extreme low light conditions and creates the glow of their eyes. It works by acting like a mirror, reflecting light hitting the back of the eyeball back onto the light receptive cells in the retina. Some of the light reflected back in this way comes out of the front of the eye, which is noticeable at night when a bright light hits a cat’s eye. Cats are not the only animals with this layer - dogs, horses and cows also have it.

Cats also have a third eyelid which provides additional protection and partially closes over the eye when the cat is blinking and sleeping. It is usually only visible in the corner of the eye.

Here are PDSA’s top tips to help keep cats’ eyes in purrfect condition:
Diet: A cat’s body is designed to function on a diet that primarily consists of protein and fat. They have a particular need for certain types of protein such as taurine, which is vital in preventing visual, heart and reproductive problems. Cats can’t produce vitamin A, needed for sight and healthy skin. These dietary components can only be obtained from animal sources, which is why cats can’t be fed a vegetarian diet. They should be fed a well balanced diet to help keep their eyes, skin and coat in good condition.

Eye infections: There are several things that can cause chronic eye infections in cats. Symptoms may include runny or red eyes or discharge. There are many treatments available to combat eye infections so seek advice from your vet as soon as possible.

Change in appearance of eyes: If owners notice any change in the eyes, especially pupil size, they should take their cat to the vet for a check-up as this could be a sign of a serious condition such as glaucoma, inflammation of the iris, or a problem with the nerves in the eye. It can also result from a problem with the brain, such as an injury, infection or tumour.