Background: Early Treatment Diabetic Retinopathy Study (ETDRS) seven-standard-field color stereoscopic retinal photography (ETDRS photos) has been a gold standard for determining diabetic retinopathy (DR) severity. The Automated Retinal Imaging System (ARIS™, model 110, Visual Pathways, Inc., Prescott, AZ) acquires seven-sequential color stereoscopic digital images (ARIS images) by a semiautomated technician-run process generally corresponding to ETDRS photos. We assessed the correlation between a single semiautomated ARIS imaging session without any re-imaging and ETDRS photos performed by a certified photographer for the determination of DR severity.
Methods: Two independent masked readers graded mydriatic ARIS images and ETDRS photos. A third masked retinal specialist adjudicated discrepancies. Correlation between the two modalities was compared using weighted-κ statistics.
Results: We evaluated 211 eyes of 106 patients with varying levels of DR. Partially ungradable images were present in 3.4% of ETDRS photos versus 31.8% of ARIS images. Exact agreement and agreement within one level between ETDRS photos and ARIS images using only completely gradable image sets occurred in 69% (κ=0.81) and 90% of cases, respectively. Exact agreement for clinically significant macular edema was 92.1% (κ=0.59). There was 100% agreement for eyes with high-risk proliferative DR. Within one level of DR severity, 100% agreement occurred for the following: questionable nonproliferative DR (NPDR), moderate NPDR, and severe NPDR.
Conclusions: Results suggest that semiautomated ARIS images compare favorably with ETDRS photos when full image sets can be obtained; however, partially ungradable image sets occurred almost 10 times more frequently with ARIS images than with ETDRS photos. In the two-thirds of cases where ARIS images can be utilized, ARIS can obtain retinal images comparable to ETDRS photos while requiring less highly trained personnel than generally needed for standard ETDRS photos.