BBC News Online health staff
Sarah Peters says she ignored her condition for a long time
Diabetics are being urged to have annual eye tests to help save their sight.
Regular eye tests can detect diabetic retinopathy - the most common cause of sight loss amongst working people in the UK.
The condition is a complication of diabetes where the blood vessels of the retina are damaged. It affects at least six out of 10 diabetics.
But, despite free eye tests, many diabetics are still ignoring their health.
Anita Lightstone, of the Royal National Institute of the Blind (RNIB), said regular tests picked up early changes in the eye, while it was still possible to get treatment.
"Early detection is vital and an eye test every year for people with diabetes is recommended.
"Eye tests are free for people who are diabetics, but do not wait until your vision has deteriorated to have an eye test."
Sarah Peters, aged 33, from Epsom in Surrey, admits she ignored her diabetes during her teens.
At the age of just 26 she temporarily lost her sight, as bursting blood vessels caused her to be blinded.
Because she had ignored her condition for so long, doctors found it difficult to get both her diabetes and her sight problems under control.
"I have been diabetic since I was 14 and was careless about taking medication.
"But my sight was fine until after I graduated from college with a fashion degree.
"I was 26 and was out ten-pin bowling with friends when my ankle collapsed.
"My bone density was very low because of the diabetes. While I was in hospital having an operation, my sight went. I was totally blind.
"I didn't know anything about sight loss and when they told me my sight might never come back I cried.
"I felt really sorry for myself and went into a deep depression.
"Losing your sight in your late 20s and realising it's never going to fully come back is frightening."
As her sight deteriorated Sarah was forced to give up her business and her self-esteem sunk to an "all-time low".
"The attitude of some sighted people was awful," she said.
"I was made to feel because I had lost my sight that I was no longer good for anything or capable of living a normal life."
Now she has retrained and works in corporate publishing, using a specially adapted computer.
She said it was vital that diabetics heeded the warnings, and got their eyes checked annually.
"I did not and my problems built up over the years," she said.
"If I had got regular checks the doctors would have noticed that I had a problem sooner and they would have been able to control it more quickly."
Emma Bunn, diabetes care adviser at Diabetes UK, said: "People with diabetes are at an increased risk of developing eye problems.
"Diabetes UK recommends that people ensure they have regular eye tests as part of their ongoing diabetes care.
"Many diabetes-related eye conditions can be successfully treated if diagnosed early enough, which can prevent unnecessary blindness."
The warning for diabetics comes as the RNIB gears up for its eye test action day on 17 September, when they will urge the importance of eye tests for everyone.