Open angle glaucoma (OAG) is the commonest type of glaucoma in white European and African people and is the commonest cause of irreversible blindness. Its onset is insidious and progression symptomless until the condition is far advanced and central vision is lost. Because of this, OAG is assumed to be a condition which should be screened for, but good evidence to support this is lacking. Risk factors for developing OAG include increasing age, raised pressure inside the eye and a history in the family. It is more common in people with African origin, may come on at an early age and is more aggressive. The field of vision (side vision) is gradually lost but changes in the appearance of the optic nerve (where it appears inside the back of the eye) usually occur first. Raised pressure inside the eye may not be present and many with raised pressure do not have glaucoma. Tests for the disease are examination of the optic nerve, measurement of eye pressure and visual field assessment. The challenge of screening is to find people with the disease at a stage when the diagnosis is not in doubt and at risk of going blind if left untreated.
The aim of this review was to determine the impact of screening on the prevalence and severity of optic nerve damage due to OAG. We searched for randomised controlled trials (RCTs) of screening versus no screening for OAG because effectiveness of screening as a means of preventing the ill effects of a disease in a population can only be demonstrated by RCTs. We identified 1360 reports of studies but none were RCTs of screening. Therefore, there is insufficient evidence to recommend population based screening for OAG. However much can be done to improve awareness of the condition and encourage those at higher risk to seek testing. In wealthy countries where there is access to high quality eye care and good health education, blindness from OAG should become increasingly rare. Much greater challenges face poor and emerging economies and countries where there is not equal access to good healthcare. The potential effectiveness of screening for OAG in preventing optic nerve damage and ultimately preventing blindness should be tested by high quality RCTs of screening.