A cataract occurs when the lens inside the front of the eye becomes cloudy and opaque, therefore reducing the amount of light that can pass though it, to the back of the eye.
Description
The lens is used to focus light onto the retina located at the back of the eye, so that the images we see are sharp and in focus.
A small part of the lens or the whole lens can be affected by a cataract and one or both eyes can be affected. The amount of visual disturbance or loss depends on this and the presence of other eye conditions such as macular degeneration (a lack of blood to the part of the retina which sees detailed and colour vision), diabetic retinopathy (when blood vessels leak blood and fluid into the eye) or gluacoma (when there is raised pressure within the eye).
Cataracts usually take a long time to form and patients may only realise that their eye sight is deteriorating after an assessment by their optician. This is vital for driving. Cataracts are more likely in older people as the lens naturally hardens and becomes cloudy, although congenital cataracts in babies may be inherited or be caused by an infection in the womb. Other causes in other age groups include eye injuries and trauma, use of steroids to treat other conditions and diabetes, causing cataract formation at an earlier age.
Medical Facts
Not everyone requires an operation. The decision to operate depends on your age, lifestyle, occupation and general health, but cataracts can only be treated surgically. This is generally a very simpe and effective precedure.
Before surgery however, advice is usually given out wearing peaked caps and sunglasses to reduce the light shining directly into the eye and about eye drops which widen the pupils so that more of the available light gets through to the back of the eye.
Usually only one eye is operated on at one time so that one eye can recover with the best vision possible before attempting the second eye.
The surgical technique to remove cataracts is known as phacoemulsification. Before surgery, eye drops are usually used to widen the pupil but this also means that you will not see anything except some blurred light.
The surgeon makes a 3mm incision on the surface of the cornea using a microscope. This incision is at the edge of the iris (coloured part of the eye) near the upper eyelid.
A special needle is inserted through this incision which emits high energy ultrasound waves which break down the lens containing the cataract. The pieces are sucked through the needle painlessly afterwhich a new artifical lens made from plastic (called an intraocular lens or IOL), is inserted and placed in the correct part of the eye. The incision is self healing and therefore does not require stitches.
Occasionally, a slightly different procedure is used called a manual extracapsular extraction where a bigger incision is made and which requires stitches for healing to take place. Here, the lens is removed in one piece and a new artificial lens inserted, but this is done less frequently as recovery times are longer.