Image Quality

Home-based community screening had much higher ungradability than darkroom-controlled health and wellness centre screening. Image quality was a central determinant of diabetic retinopathy screening performance. Staged mydriasis could be considered for ungradable images, but it was not implemented in this study. Cataracts, small pupils, older age, longer diabetes duration, macular scars and miosis contributed to ungradable images. Ungradable images can weaken screening effectiveness by increasing false negatives and reducing sensitivity.