Assessing the likely effectiveness of screening older people for impaired vision in primary care.

Screening for visual impairment is frequently included in multiphasic screening assessments for older people, although evidence for the effectiveness of screening from randomized trials is lacking. This paper uses previously developed criteria for assessing the likely effectiveness of community screening programmes to review the non-trial evidence around visual screening. Unreported or undiagnosed visual impairment is common among older people and is associated with considerable morbidity. Testing for visual acuity is easy and quick, but may not accurately reflect the level of functional disability caused by the visual problem in everyday living. Effective therapeutic interventions exist for most symptomatic patients, but the effects of treating unreported visual impairment detected by screening have not been evaluated. Existing barriers to effective treatment for older people with symptomatic visual problems include financial costs to the patient, and an inability of ophthalmic services to meet demand. These same factors may be barriers to the uptake of treatment following screening. Further work is needed to assess the needs of older people with unreported visual problems, and to clarify barriers to effective screening.