Photographic Screening for Diabetic Retinopathy

Diabetic retinopathy is the best studied microvascular complication of diabetes. It has a well-understood natural history and treatment options that have been validated. Available treatments include glycemic and hypertensive control, laser therapy, and victrectomy. Detailed screening guidelines are also readily available. In the US, 42% of patients are not screened appropriately. There are numerous reasons for this low adherence with screening guidelines, including cost, inconvenience, access to trained screeners, and ignorance of the benefits of screening. The Early Treatment of Diabetic Retinopathy Study (ETDRS) 7 standard field imaging is accurate and reproducible, showing good sensitivity and specificity. This method is also time consuming, uncomfortable to patients, and requires access to qualified graders. Another option for screening is ophthalmoscopy, which is examiner dependent and has poor sensitivity, but shows good specificity.

There are numerous outstanding issues in this area. Pupil dilation is considered inconvenient by patients and decreases adherence with screening recommendations. Use of multiple fields increases sensitivity and specificity, but it also increases the need for skilled readers. Images are subject to interpretation and error. One strategy that may prove to be beneficial for retinopathy screening is telemedicine systems that allow screening to be done in a primary care setting, and the images are then transmitted to a grading center for interpretation.

Numerous telemedicine options (eg, Joslin Vision Network, Ophthalmic System, Eyetel) exist and have been validated against more traditional screening methods. The ideal telemedicine system would use a single field, digital image in a non-mydriatic fashion, it would have acceptable sensitivity and specificity, and it would be accessed through a primary care provider office. Such a system would address many of the barriers to diabetic retinopathy screening. It is important to note, however, that telemedicine is not a substitute for a complete ophthalmologic exam, and numerous questions pertaining to its use have yet to be answered. Specifically, the long-term acceptability to patients, its applicability to diverse populations, and validation of its financial and visual benefits must be addressed in future work.