Untreated primary open angle glaucoma (POAG) is a blinding optic neuropathy. Timely medical or surgical treatment is effective in slowing the rate of optic nerve damage and delaying the onset of visually disabling field loss,1 but treatment is only effective in prevention, and there is as yet no means of reversing established axon loss. In the United Kingdom, around 250 000 people suffer from POAG with visual field loss.2 3 The disease accounts for 15% of the 1500 new registrations for blindness in England and Wales per year.4 5

The insidious nature of POAG, its potential detection by relatively simple, non-invasive, screening tests at an early stage, and the existence of treatments effective at preventing disabling visual loss constitute a cogent argument for screening. Consistently, over many years and in numerous different populations, researchers have found that 50% of the disease remains undetected in the community,6 and one in five of those with newly confirmed disease already have advanced field loss.7 Clearly, new approaches to the detection of POAG are required if we detect only half the prevalent disease. To target individuals at increased risk would appear to constitute sound clinical and economic practice.8 9

The “Guidelines for the management of ocular hypertension and primary open angle glaucoma”10 recently published by the Royal College of Ophthalmologists, define risk factors for the development of POAG. These include a positive family history in a first degree relative, high myopia, black race, and diabetes. These groups would therefore appear suitable for targeted screening.

The purpose of this review is to examine the evidence that one of these factors, diabetes mellitus, is a risk factor for POAG. It is recommended that all people with diabetes should receive annual screening for diabetic retinopathy,11 and if there truly is …