A fundus camera dedicated to the screening of diabetic retinopathy in the primary-care physician's office

PURPOSE. To increase the number of diabetic patients being screened for retinopathy, an instrument, the DigiScope, was specifically designed to operate in primary-care physicians' offices. The DigiScope is described and its automated functions are evaluated. METHODS. The DigiScope consists of a semiautomated optical head to acquire fundus images, evaluate visual acuity, and transmit the data to a remote reading center through telephone lines. Normal volunteers and 17 consecutive diabetic patients visiting their primary-care physician were recruited, and non-ophthalmic staff performed the acquisition session. RESULTS. The pupil center and working distance were set automatically. Centering was achieved within 750 μm in less than 500 ms. The fundus was successfully focused by an automated algorithm, and an imaging session covering 71° of the posterior pole of both eyes lasted 5.6 ± 2.4 minutes. It was found that a file-compression ratio of 12 did not degrade the clinical information and allowed data transfer in less than 6 minutes. A pilot study in normal eyes showed that the DigiScope images yielded the same amount of details as conventional color fundus photographs obtained by an expert photographer. CONCLUSIONS. The DigiScope fulfills the instrumental requirements for a practical and cost-effective tool to acquire data needed to identify diabetic patients who must be referred to an eye-care specialist. Widespread screening with the DigiScope may help reduce the risk of vision loss in an estimated 4 million individuals in the United States alone, who currently do not undergo an annual eye examination.