Screening for Diabetic Retinopathy by One-Field, Non-Mydriatic, 45° Digital Photography Is Inadequate

Abstract

Purpose: To evaluate the sensitivity and specificity of one-field, non-mydriatic, 45° digital photography for screening for diabetic retinopathy compared to indirect ophthalmoscopy using a slit-lamp, the reference standard. Methods: A total of 100 consecutive diabetic patients (200 eyes) who underwent digital fundus photography and ocular examinations from June 2002 to November 2002 were included in this retrospective study. The patients, recruited from a hospital-based, retina referral practice, underwent 45°, non-mydriatic, digital fundus photography using a non-mydriatic fundus camera. One image was obtained focusing the mid fundus between the optic disc and the macula. The fundus images were printed and graded by endocrinologists and a retinal specialist separately. The patients also underwent complete standard ocular examinations as the reference method for determining diabetic retinopathy, including dilation of their pupils and slit-lamp biomicroscopy done by ophthalmologists. The sensitivity and specificity of the digital photographic method were calculated by comparison to the reference method. Results: The sensitivity and specificity of the retinal specialist’s diabetic retinopathy grades were 53.8 and 89.0%, respectively. The sensitivity and specificity of the endocrinologists’ grades were 45 and 75.3%, respectively. The false negative rates were 22 and 21.5% for endocrinologists and the retinal specialist, respectively. Conclusions: Screening for diabetic retinopathy using one-field, non-mydriatic, 45° digital photography is inadequate.