A Novel Hybrid Fixed and Mobile Ultra-Widefield Imaging Program for Diabetic Teleretinopathy Screening

Abstract

Purpose: To describe a new approach for telemedicine screening of diabetic retinopathy (DR) using a combination of a mobile ultra-widefield camera, mounted in a van and able to travel to areas of need, and several fixed-location cameras in high-volume clinics and to report predictors of DR in a diverse urban population of 2788 patients.

Design: Cross-sectional study.

Participants: Two thousand seven hundred eighty-eight patients enrolled in the San Francisco Health Network who underwent DR screening using the novel hybrid telemedicine system.

Methods: The study was carried out at Zuckerberg San Francisco General Hospital in the San Francisco Health Network. A van was specially equipped to allow an ultra-widefield fundus camera to be mounted inside, and the van was sent with a technician to primary care clinics throughout the city on a rotation schedule determined according to clinical need. Additional fundus cameras were placed in several high-volume clinic locations. Patient demographic and clinical information was collected at the time of screening. Photographs were transmitted to a reading center and were graded for DR and other findings by trained readers.

Main outcome measures: Prevalence of DR subtypes and odds ratios for development of DR and proliferative DR (PDR).

Results: The hybrid mobile and fixed-location ultra-widefield camera screening system was able to be deployed to carry out the telemedicine screening program for diabetic patients throughout the city of San Francisco referred for screening during the period of the study. Of 2788 patients screened, 736 (27%) were found to have DR. Of these, 34 (5%) had PDR, and 702 (95%) had nonproliferative DR. In multivariate analysis, factors found to be associated with development of any DR were diabetes duration, hemoglobin A1C level, insulin use, and end-organ damage. Diabetes duration was the only factor associated with PDR.

Conclusions: Diabetic retinopathy screening can be accomplished in an urban setting using a combination of fixed-location and mobile ultra-widefield cameras to extend the reach of the screening opportunity throughout a health network. In a diverse group of patients, factors associated with DR and PDR were identified and support ongoing efforts to screen for retinopathy and maintain diabetic control.