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Kristi Dohm, Nancy Barrett, Kyle McDaniel, Barbara A Blodi, Amitha Domalpally; Comparison of Diabetic Retinopathy Severity Level Assessment Between Standard 7-field Imaging and Ultrawide Field Color Imaging. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5333.
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© ARVO (1962-2015); The Authors (2016-present)
Diabetic retinopathy has traditionally been evaluated using the Early Treatment Diabetic Retinopathy Severity Scale (ETDRS) from 7-field (7F) stereoscopic color photographs and is considered the gold standard. Ultrawide field color (UWF-C) imaging is now available for viewing a wider area of the retina. We assessed DR severity levels from standard 7-field images and compared them to the 7-field area equivalent of the UWF-C images.
DR severity was determined using ETDRS 12 step scale from both 7F and UWF-C images. A grid outlining the 7F area of the UWF-C was centered on the image with peripheral areas masked (masked grid, Figure 1). The ETDRS level that was determined using this grid was called the UWF 7F DR level. The ETDRS level that was determined using standard 7F images was called 7F DR level. All images were evaluated independently using double read with adjudication.
Of the 152 pairs of images evaluated, DR level was ungradable in 3 (1.9%) 7F images and 17 (11.2%) UWF-C images. Of the 133 pairs of gradable images, the 7F DR level was well distributed with 13 (9.8%) showing no or early DR, 44 (33.1%) with mild-moderate non-proliferative DR, 55 (41.4%) with moderately severe – severe non-proliferative DR, and 21 (15.8%) with proliferative DR. Comparing 7F DR level to UWF 7F DR level (masked grid), agreement was exact in 47.0 % of the eyes and within 1 step in 84.2 % (weighted kappa 0.59 [SE 0.05]). Of the 70 eyes with disagreement between DR levels, 41 (58.6%) were due to a lower grade assessment in UWF DR level compared to 7F DR level.
The study shows moderate agreement between DR levels determined within standard 7F imaging and UWF-C images. The ungradable rate is higher with UWF-C images. In eyes with disagreement on DR level, the level is more likely to be lower in UWF-C images; this is potentially due to difficulty in visualizing intraretinal microvascular abnormalities (IRMA).
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
Figure 1: Masked Grid UWF-C image showing 7F area
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