Diabetic retinopathy phenotypes on ultrawide field retinal imaging in an Indian population

Purpose: To study the distribution of lesions of diabetic retinopathy (DR), cotton wool spots (CWS) and scattered exudates on ultra-widefield images (UWFI) to better define DR phenotypes in Indians. Methods: This multicenter cross-sectional observational study on UWFI in individuals with DR was conducted across four tertiary eye care centres in South India. The Early Treatment Diabetic Retinopathy Study (ETDRS) grid was superimposed on the UWFI and each image was analysed for the distribution of the retinal lesions. Results: Out of a total of 1002 eyes of 1002 patients with gradable images, 459 eyes (46 %) had predominantly peripheral retinal lesions (PPL), of which haemorrhages /microaneurysms (86.1%) were the most frequent lesions. Only 5.5 % of eyes had retinal neovascularization limited to outside the 7-field. Strong agreement was demonstrated in the grading of retinopathy using ETDRS and UWFI (κ = 0.9). 15.3% eyes had a higher grade of DR when graded on UWFI compared to 7-field ETDRS grid. Scattered exudates and cotton wool spots on UWFI are prevalent in Indian eyes with DR. Scattered exudates on UWFI was more prevalent in eyes with PPL and was associated with increasing severity of diabetic retinopathy. Conclusion The presence of PPL and scattered exudates on UWFI are associated with increasing DR severity in Indians and these findings need to be considered in new classifications of DR.