Screening for Diabetic Retinopathy in Rural Area Using Single-Field, Digital Fundus Images
Paisan Ruamviboonsuk, MD*, Nattapon Wongcumchang, MD*, Pattamaporn Surawongsin, MD**, Ekchai Panyawatananukul, MD***, Montip Tiensuwan, PhD****
Affiliation : * Department of Ophthalmology, Rajavithi Hospital ** Department of Ophthalmology, Lerdsin Hospital *** Director of Kabcheang Community Hospital, Surin **** Department of Mathematics, Faculty of Science, Mahidol University
Objective : To evaluate the practicability of using single-field, 2.3 million-pixel, digital fundus images for
screening of diabetic retinopathy in rural areas.
Materials and Methods : All diabetic patients who regularly attended the diabetic clinic at Kabcheang
Community Hospital, located at 15 kilometers from the Thailand-Cambodia border, were appointed to the
hospital for a 3-day diabetic retinopathy screening programme. The fundi of all patients were captured in
single-field, 45(cid:31), 2.3 million-pixel images using nonmydriatic digital fundus camera and then sent to a
reading center in Bangkok. The fundi were also examined through dilated pupils by a retinal specialist at
this hospital. The grading of diabetic retinopathy from two methods was compared for an exact agreement.
Results : The average duration of single digital fundus image capture was 2 minutes. The average file size of
each image was 750 kilobytes. The average duration of single image transmission to a reading center in
Bangkok via satellite was 3 minutes; via a conventional telephone line was 8 minutes. Of all 150 patients,
130 were assessed for an agreement between dilated fundus examination and digital fundus images in
diagnosis of diabetic retinopathy. The exact agreement was 0.87, the weighted kappa statistics was 0.74. The
sensitivity of digital fundus images in detecting diabetic retinopathy was 80%, the specificity was 96%. For
diabetic macular edema the exact agreement was 0.97, the weighted kappa was 0.43, the sensitivity was
43%, and the specificity was 100%.
Conclusion : The image capture of the nonmydriatic digital fundus camera is suitable for screening of dia-
betic retinopathy and single-field digital fundus images are potentially acceptable tools for the screening.
The real-time image transmission via telephone lines to remote reading center, however, may not be practical
for routine diabetic retinopathy screening in rural areas.
Keywords : Diabetic retinopathy screening, Digital screening, Nonmydriatic fundus camera
