By the age of 80 around half of us will develop a cataract – a cloudy patch in the lens of the eye. This is the leading cause of impaired vision throughout the world, but a surgical procedure can cure the problem in 95 per cent of cases.

With age, protein deposits may build up in the lens of the eye, causing blurred, hazy or cloudy vision, muted or yellowed colouring, glare and difficulty seeing in low light. This clouding of the lens is a cataract, and it may affect one or both eyes.

Women and people with light- coloured eyes or a family history of cataracts are more at risk, as are those with diabetes or high blood pressure. Exposure to sunlight or radiation, eye injury or surgery, excess alcohol, steroid use and obesity are also risk factors, smoking can increase your chances of cataracts by 48 per cent, according to a study .

At first a change of prescription in glasses or contact lenses may help. But cataracts usually worsen over time, so surgery is generally needed.

What’s involved
Modern treatment is speedy and safe, with an operation usually carried out under local anaesthetic to replace the cloudy lens with a clear artificial one. One eye is usually done at a time and vision improves almost immediately, thought it may be blurry at first. If you also have refractive errors, such as short sightedness, replacement lenses can correct this.

Managing your diabetes well and keeping blood sugar levels stable helps to prevent diabetic retinopathy. Hypertensive retinopathy is a similar form of retinal damage that occurs in people with high blood pressure. Again changes can be detected during an eye test. Later on, double or dimmed vision, headaches and sometimes vision loss can occur. The retina may recover when blood pressure is controlled.

uRETINAL DETACHMENT This is more common with age, especially in people who are short-sighted, have a family history of the condition, or have had an eye injury or cataract surgery. It happens when the retina peels away from the layer of supporting cells at the back of the eye. A common warning signal is a sudden intense burst of floaters and/or flashing lights. As detachment occurs, the effect is of a curtain dropping over the field of vision. This is a medical emergency, and if you suspect it, seek help straight away: surgery or laser treatment can prevent sight loss in over 90 per cent of cases.