Fundus polaroid screening for diabetic retinopathy. Is one print per patient enough?

The CR3-45 NM Canon nonmydriatic fundus camera detects relevant diabetic retinopathy with high sensitivity. To determine whether examination of one eye per patient would suffice for screening purposes, 473 pairs of standard 45 degree fundus Polaroid prints obtained with the Canon camera were assessed from 167 patients with and 306 without diabetic retinopathy. On the basis of considering only one eye per patient, absence of retinopathy would have been diagnosed in 336 patients, with 9% of the diagnoses false negative. One hundred thirty-seven of the 167 patients with retinopathy in at least one eye would have been diagnosed correctly by considering one eye per patient (sensitivity 82%, specificity 100%). Thus, a standard 45 degree fundus Polaroid print from one eye per patient may suffice for screening purposes if the picture is free from diabetic abnormalities. Otherwise, both eyes should be examined immediately, and the patient should be referred to an expert ophthalmologist who specializes in diabetic retinopathy for confirmation of the diagnosis and staging of diabetic retinopathy status.