Use of mobile screening unit for diabetic retinopathy in rural and urban areas.

Objectives: To compare the effectiveness of a mobile screening unit with a non-mydriatic polaroid camera in detecting diabetic retinopathy in rural and urban areas. To estimate the cost of the service.
Design: Prospective data collection over two years of screening for diabetic retinopathy throughout Tayside.
Setting: Tayside region, population 390,000, area 7770 km2.
Subjects: 961 patients in rural areas and 1225 in urban areas who presented for screening.
Main Outcome Measures: Presence of diabetic retinopathy, need for laser photocoagulation, age, duration of diabetes, and diabetic treatment.
Results: Compared with diabetic patients in urban areas, those in rural areas were less likely to attend a hospital based diabetic clinic (46% (442) v 86% (1054), p < 0.001); less likely to be receiving insulin (260 (27%) v 416 (34%), p < 0.001 and also after correction for differences in age distribution); more likely to have advanced (maculopathy or proliferative retinopathy) diabetic retinopathy (13% (122) v 7% (89), p < 0.001); and more likely to require urgent laser photocoagulation for previously unrecognised retinopathy (1.4% (13) v 0.5% (6), p < 0.02). The screening programme cost 10 pounds per patient screened and 1000 pounds per patient requiring laser treatment.
Conclusion: The mobile diabetic eye screening programme detected a greater prevalence of advanced retinopathy in diabetic patients living in rural areas. Patients in rural areas were also more likely to need urgent laser photocoagulation. Present screening procedures seem to be less effective in rural areas and rural patients may benefit more from mobile screening units than urban patients.