Prevalence of primary open angle glaucoma in general ophthalmic practice in the United Kingdom.

Aim: To estimate the predicted prevalence of primary open angle glaucoma (POAG) from the activity of a local ophthalmology department.

Method: Using clinic audit data, the local incidence and prevalence of POAG in the registered population of two primary care trusts were calculated.

Results: The local derived prevalence estimate for POAG was 978 per 100 000 people aged 40-89 years (95% CI 753 to 1272) compared with the expected prevalence from a published model of 1230 people per 100 000 people aged 40-89 years.

Conclusion: The derived prevalence was not statistically significantly different from that predicted. Based on the published evidence that about half of the POAG cases are undetected, it would have been expected that local audit figures would have yielded figures about 50% lower than the epidemiological model. The main reason for this higher prevalence is thought to be differences in the diagnostic criteria used. This lack of consensus on the case definition for POAG is a deficit, which will hamper future needs assessment.