Britain’s increasing number of obese adults and children face twice the risk of losing their sight from a range of degenerative eye conditions, a report from the Royal National Institute of the Blind said on Wednesday.

Last month the Department of Health warned that nearly a third of men in England would be obese by 2010 if no measures were taken to tackle the problem.

Obesity is already recognised as one of the leading preventable causes of death from heart disease and diabetes but the RNIB report said it was also a key factor in sight loss.

“Most people wrongly assume that if they don’t have any obvious problems with their sight, everything must be fine,” said RNIB eye health consultant Barbara McLaughlan.

“With the huge increase in obesity that we have seen in recent years, many people are now jeopardising their sight in later life.”

The report highlighted the increased risk obese people have of developing three major causes of sight loss:

- age-related macular degeneration (AMD), a condition affecting the retina which is the leading cause of sight loss in the UK

- diabetic retinopathy, a progressive blurring of vision developed by 60 percent of type 2 diabetes sufferers

- cataracts, a clouding of the eye lens responsible for one in four cases of sight loss in people over 75

It said obese people doubled their chances of suffering AMD and cataracts, as well as having up to 10 times the risk of developing type 2 diabetes.

“To safeguard sight we recommend people maintain a healthy weight, eat lots of fresh fruit and vegetables, take exercise to improve general health, don’t smoke and most importantly have regular eye tests,” said McLaughlan.

“Many thousands of people lose their sight each year through conditions that could have been treated if picked up early enough through an eye test.”

People are classed as obese if their body mass index (BMI), defined as their weight in kilograms divided by the square of their height in metres, is 30 or above.