Tele-ophthalmology screening for retinal and anterior segment diseases

A digital indirect ophthalmoscope (DIO) was developed and tested for use in tele-ophthalmology screening for posterior and anterior segment diseases. Using custom software, images from the DIO were digitized, compressed, stored and transmitted to a centralized eye clinic for interpretation. A total of 43 subjects were primarily screened for glaucoma using the DIG, a hand-held fundus camera and a stereo fundus camera. The photographic slides from the stereo fundus camera were used as gold standards. Images (390 x 300 pixels x 3 bits) were stored using a laptop computer together with patient information. Image quality received at the central eye clinic was good and showed adequate diagnostic information. An ophthalmologist estimated cup-disc ratios and graded the quality of the images. The sensitivity and specificity of each instrument was calculated. A high sensitivity and specificity was found when using the DIG, indicating that it could be used in tele-ophthalmic screenings. Further modifications are needed to make the instrument more user-friendly and to enable it to be used with undilated pupils, so that it can be easily operated by health-care personnel in remote areas. The camera can also be used to image gross external eye pathology.