Thousands of diabetics are at risk of losing their sight because almost 60% of primary care trusts (PCT) fail to meet screening targets, according to a charity.
Patients are at risk of diabetic retinopathy, a disease which is the main cause of blindness in the UK's working population.
In 2003, the government set targets saying diabetics could expect to be screened for the condition every year "as a minimum".
But government figures showed that a third (32.3%) of diabetics in England did not receive screening - equating to 762,673 people.
Campaign charity Diabetes UK warned that patients who do not receive annual digital retinal screening and who are not recalled every year risk losing their sight.
A total of 94 out of 152 PCTs failed to meet their target of offering people with diabetes the chance to be screened, it said.
Simon O'Neill, director of care, information and advocacy services at Diabetes UK, said: "If retinopathy is caught early and treated properly then blindness can be prevented in 90% of cases, so the simple screening process really could save the sight of hundreds of thousands of people."
Retinal screening spots signs of retinopathy, a condition caused when blood vessels in the retina of the eye become blocked, leaky or grow haphazardly.