Screening for diabetic retinopathy using a digital non-mydriatic camera compared with standard 35-mm stereo colour transparencies

Purpose: To investigate the use of a digital non-mydriatic camera for determining the ETDRS clinical level of diabetic retinopathy, and to evaluate its use in a screening setting to appropriately determine the need for referral to an ophthalmologist (ETDRS level ≥ 35). Methods: A total of 83 patients with diabetes were photographed with and without pharmacological pupil dilation at an ophthalmology department using a digital non-mydriatic camera, obtaining two sets of five non-stereoscopic, 45 degree field images of each eye. ETDRS seven standard field, 35-mm stereoscopic colour fundus photographs were also obtained. A subgroup of 59 patients was photographed at an optician's shop using the digital non-mydriatic camera without pupil dilation. Results: There was substantial agreement between the clinical level of diabetic retinopathy assessed from the 35-mm photographs and the digital images: the ophthalmology department (κ=0.76) with pupil dilation and (κ=0.66) without pupil dilation, respectively, and at the optician's (κ=0.60 without pupil dilation). With respect to the need for referral to an ophthalmologist, there was almost perfect agreement in the ophthalmology department (κ=0.88) with pupil dilation and (κ=0.84) without pupil dilation, respectively, and those taken at the optician's (κ=0.87 without pupil dilation). Conclusion: A digital non-mydriatic camera may be used in a screening situation to appropriately determine the need for referral to an ophthalmologist (ETDRS level ≥ 35).