A cataract is where the lens in the eye becomes progressively hazy, making vision blurry. The lens lies behind the iris (the coloured part of the eye) and is responsible for focusing light to a point on the back of the eye. The lens also changes shape to help focus on near objects.
There are numerous types of cataract and they can occur at any age, though they are rare in the young. Cataracts have numerous causes including steroids and trauma but the majority are due to age. The ‘usual’ age related cataract will be due to continuous growth of the lens throughout life resulting in a loss of flexibility and later progressive haze. The loss of flexibility is why most people need reading glasses in their forties.
As well as reducing clarity, cataracts can cause glare as bright lights scatter on reaching the cataract. For this reason a peaked cap or wide brim hat is very useful as they help block out the sun, a major source of glare. If sunglasses are preferred then polarised lenses should be used.
Cataracts can also result in double vision and due to a progressive yellowing of the lens can alter colours, they tend to look faded or washed out.
The majority of cataracts can be removed, usually under local anaesthetic and requiring no stitches. Improvement in vision is fairly instant but the healing process can take several months. A new spectacle prescription is usually required.