By Dr Reeja George P.*
Those captivating glimmering limpid pools of blue, green, yellow, orange and a host of other colours can be quite bewitching! A cat’s eye, especially when she gazes lovingly at you, can literally carry one into another world. Just as in humans, taking care of your cat’s eyes will ensure that your fluffy ball of joy will have a good quality of life.
How is your cat’s eye different from yours?
Over the time and through normal process of evolution, a cat’s eye has developed unique features that enable it to have clear indoor and outdoor vision. The way it functions in general is very similar toa human eye especially with regard to basic functions. However, there are some differences that are unique to a cat’s eye so that it can improve its success rate while catching a prey and also escape any danger lurking in the dark. Two features of a cat’s eye stand out as distinct from a human eye – First is the presence of a ‘third eyelid’ that is a pale membrane like structure seen between the eyeball and inner corner of the lower eyelid. The third eyelid ensures that your cat’s eye is kept moist always, besides cats also use it to cover their eye ball as a protective measure when they fight with other cats. Cats are additionally endowed with a special tissue inside their eyes called the tapetum lucidum that absorbs excess light and makes your cat’s eye six times more sensitive to light as compared to yours.
Healthy cat eyes
Generally, your cat’s eyes will be bright and clear and those pupils – those black slits within the coloured part of the eye – will be of equal size. The inner parts of eyelids will have a healthy pinkish hue and the third eyelid will be intact and not protruding out.
It’s always important to watch out for tell tale signs of eye problems in your cat because in many cases if you seek help from a vet early, you will help your cat in retaining its vision. So be alert and watch out if you see your cat blinking frequently, which means that her eyes have become extra sensitive to light, or if you see any discharge around her eyes. She may also try to rub her eyes and sometimes find it difficult to move about as she usually would have done. Vision problems may also be signalled by her difficulty in finding things that she commonly uses, such as her litter box or her food bowl; she may move around in a clumsy manner bumping into things and find it difficult to run up a flight of stairs. All these are signs that she may have problems with her eyes and she should be seeing her vet as soon as possible.
Causes of eye problems
There are quite a variety of causes that could cause an eye infection in a cat. The main causes are infectious in nature and include viruses like the Feline Herpes Virus (FHV), the Feline Leukaemia Virus (FeLV), the Feline Immuno Deficiency Virus (FIDV) and the Feline Infectious Peritonitis Virus (FIP). In addition to these, parasites such as Toxoplasma and yeast such as fungi like Cryptococcus may also cause eye problems in your cat.
As a cat owner you may have faced a condition where in your cat wakes up to runny eyes that later progress to pink coloured eyes and is called pink eye or conjunctivitis, quite similar to the condition in humans. This condition is commonly associated with cat flu and other bacterial or viral cat infections. It is highly contagious among cats –and not humans – so you will have to take extra care in case you have more than one cat at home. You have to take your cat to a vet who will give you medicines so that issues related to the eye becoming dry, and the cat scratching it, are controlled. It is not a very serious problem if treated early, but if you delay showing her to a vet, things may become complicated.
Cataractsare another issue of concern for your cat’s eye health. A cataract is a condition where a cat’s eye lens becomes cloudy or even opaque. Normally, your cat’s eye lens would be translucent, adjusting its shape to focus light rays on the light sensitive inner lining of eyeball where images are formed, the retina. Once the lens becomes opaque, your cat’s vision will be affected. Cataracts can occur at any age, though it is more common in older cats due to the process of aging. There could be a lot of causes that could lead tocataracts in cats some of which are certain chemicals, toxins as well as other underlying problems such as diabetesand high blood pressure.
Severe problems of a cat eye are those that can lead to a loss of vision to varying degrees, and in some cases even blindness. It is a very depressing thing for anyone, be it us or the cat. Potential culprits that could lead to blindness include a condition known as uveitis in which the middle area of the eye gets inflamed. This condition occurs along with major viral diseases mentioned earlier such as FIV, FeLV and FIP. Here the onset of a permanent loss of vision is gradual and not sudden. Common signs that could signal an impending eye emergency include a swelling of the third eyelid so that it protrudes out of the eye, your cat may have a squint and sometimes her eyes may appear unusually enlarged. The second disorder that is commonly associated with blindness in cats can be visualised as a detachment of the retina – the part of the eyeball associated with vision. This situation is associated with other concurrent illnesses such as kidney disease and conditions of thyroid. Sometimes, your cat could also have high blood pressure. This is a very serious condition that could result in loss of vision if left untreated.
Other eye problems
Other causes of eye problems include trauma caused by objects or attacks of other cats –in case your cat goes out – and problems associated with tumours of the eye or other parts near the eye.
Keeping your cat safe
Many of the viral infections associated with eye problems in cats can be prevented by kitten-hood vaccination. So, as a responsible pet owner, it is important that you see your vet before you get a kitten; familiarize yourself with what all vaccinations she will have to take and ensure that she gets them in time. Other than this, just as we have our checkups, have your cat’s eyes checked up once in a while, especially, if she has difficulty in navigating herself about the home or if she has other concurrent illnesses.
* Associate Professor, Department of Veterinary and AH Extension, College of Veterinary and Animal Sciences, Mannuthy, Kerala Veterinary and Animal Sciences University, Thrissur, Kerala 680 651