Background: Early treatment for diabetic retinopathy is effective at saving sight, but dependent on pre-symptomatic detection. Although 60% of people with diabetes have their eyes examined annually, few UK health authorities have systematic programmes that meet the British Diabetic Association's standards for sensitivity (> 80%) and specificity (> 95%). Screening is generally performed by general practitioners and optometrists, with some camera-based schemes, operated by dedicated staff. The National Screening Committee commissioned a group to develop a model and cost estimates for a comprehensive national risk-reduction programme.
Ophthalmoscopy: Evidence indicates that direct ophthalmoscopy using a hand-held ophthalmoscope does not give adequate specificity and sensitivity, and should be abandoned as a systematic screening technique. Indirect ophthalmoscopy using a slit lamp is sensitive and specific enough to be viable, and widespread availability in high street optometrists is an advantage, but the method requires considerable skill.
Photographic schemes: The principal advantage of camera-based screening is the capturing of an image, for patient education, review of disease progression, and quality assurance. Digital cameras are becoming cheaper, and are now the preferred option. The image is satisfactory for screening and may be transmitted electronically. With appropriate training and equipment, different professional groups might participate in programme delivery, based on local decisions.
Cost issues: Considerable resources are already invested in ad hoc screening, with inevitable high referral rates incurring heavy outpatient costs. Treatment for advanced disease is expensive, but less likely to be effective. The costs of a new systematic screening and treatment programme appear similar to current expenditure, as a result of savings in treatment of late-presenting advanced retinopathy.
Conclusion: A systematic national programme based on digital photography is proposed.