Abstract
Purpose :
Ultrawide Field color (UWF-C) images enable visualization of peripheral retina which has led to a change in the assessment of diabetic retinopathy (DR). We evaluated DR grading both within the standard 7 fields (7F) of UWF-C images and the entire UWF-C image. We compared DR severity levels between the 7F area and the entire UWF-C image to assess the impact of peripheral retinal imaging on DR severity assessment.
Methods :
DR severity was determined using ETDRS 12 step scale from UWF-C images. A grid outlining the 7F area of the UWF- C was centered on the image with peripheral areas masked (figure 1). The ETDRS level that was determined using this grid was called the UWF 7F DR level. The grid was then removed and the peripheral retina was included in a second assessment of the DR level. The level determined after the unmasking of the image was called the Global DR level (figure 2.) All images were evaluated independently using double read with adjudication.
Results :
Of the 152 pairs of images evaluated, UWF 7F DR level was ungradable in 17 eyes (11.1%) and global DR level could not be assessed in 27 eyes (17.8%). Of the 125 pairs of gradable images, the UWF 7F DR level was well distributed with 6 (4.8%) showing no or early DR, 61 (48.8%) with mild-moderate non-proliferative DR, 40 ( 32.0%) with moderately severe – severe non-proliferative DR, and 18 (14.4%) with proliferative DR. Comparing UWF 7F DR level (masked grid) to UWF Global DR level (unmasked grid), agreement was exact in 90% of the eyes and within 1 step in 97.6% (weighted kappa 0.88 [SE 0.03]). There were 13 eyes (10.4%) where DR level changed by 1 or more steps due to peripheral lesions not visible in the 7F area, and 2 eyes (1.6%) where the DR level changed from non-proliferative to proliferative DR due to peripheral neovascular lesions.
Conclusions :
The study shows almost perfect agreement between DR levels determined within 7F area and global assessment using UWF-C images. The ungradable rate is high with UWF-C images, particularly when assessing global levels. Peripheral lesions can alter DR severity assessment in about 10% of eyes, with peripheral proliferative changes affecting the severity in <2%.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.