Ahmed et al. (1) concluded that nonmydriatic digital stereoscopic retinal imaging is a sensitive and specific method for the screening and diagnosis of diabetic retinopathy that may help improve compliance with the standards of eye care for patients with diabetes. This strategy seems to be a good option in a country like India, where the ophthalmologist-to-population ratio is estimated to be nearly 1:100,000 (2,3). The ratio is close to 1 per 219,000 in rural areas (4), and 70% of the ophthalmologists are located in urban areas, where ∼23% of the population of India resides. According to a report by the American Academy of Ophthalmology (5), single-field fundus photography can serve as a screening tool for diabetic retinopathy to identify patients with retinopathy for referral.
We compared single-field 45° nonmydriatic photographs centered on macula and single-field 45° mydriatic photographs with dilated fundus evaluation by a retinal specialist in 135 eyes of 68 diabetic patients who attended two diabetic retinopathy screening camps in the rural areas of Thiruvanamalai, district of Tamilnadu. The images were converted to DICOM (Digital Imaging and Communications in Medicine) format by picture archival and communication software (PACS; Vipro Infotech, Germany) and transferred to the hub at a tertiary eye care base hospital at Chennai, Tamilnadu, by satellite link using very small aperture terminal hardware with a transmission rate of 384 kb/s. Another retinal specialist sitting in the hub evaluated all of the images in real time using a Sony videoconferencing system.
In our study, the nonmydriatic technique of photography was found to have a sensitivity of 62.5% (95% CI 24–91) and a specificity of 98.7% (93–99) when compared with indirect ophthalmoscope. The mydriatic technique of photography had a sensitivity of 70% (35–93) and a specificity of 98% (93–99) when compared with indirect ophthalmoscope. By using three nonsimultaneous 45° field stereoscopic fundus images, as described by Ahmed et al. (5), we can expect an improvement in the sensitivity of the nonmydriatic technique. Thus, three-field nonmydriatic fundus images transmitted via satellite can be a good alternative in a country like India, where health care facilities and personnel are scarce compared with patient load.
