Predictive Value of the OCT Double-Layer Sign for Identifying Subclinical Neovascularization in Age-Related Macular Degeneration

Abstract

Structural OCT images from eyes with nonexudative age-related macular degeneration (AMD) were graded for the presence of a double-layer sign to determine if the double-layer sign predicted subclinical macular neovascularization (MNV). Prospective, observational study. Nonexudative AMD patients with and without subclinical MNV identified by swept-source (SS) OCT angiography (OCTA). Participants were enrolled prospectively into an SS OCTA imaging study. A set of test scans with and without subclinical MNV was compiled to assess the ability of trained graders to identify nonexudative type 1 MNV. The graders evaluated only the structural OCT B-scans of those eyes. The presence of a double-layer sign was used as a predictive sign for subclinical type 1 MNV. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) from 2 separate gradings were calculated and compared. The association between the presence of a double-layer sign and subclinical type 1 MNV. One hundred eyes with nonexudative AMD from 94 patients were used for this study. The test set contained 64 eyes with intermediate AMD, which included 20 eyes with subclinical MNV, and 36 eyes with late AMD, which included 13 eyes with subclinical MNV. Two junior graders read the scans separately then reached a consensus grading. They detected a double-layer sign in 24 of 33 eyes with subclinical MNV and did not detect a double-layer sign in 56 of 67 eyes without MNV. Their sensitivity, specificity, PPV, and NPV were 73%, 84%, 69%, and 86%, respectively. The senior grader detected a double-layer sign in 29 of 33 eyes with subclinical MNV and did not detect a double-layer sign in 58 of 67 eyes without MNV, achieving a sensitivity, specificity, PPV, and NPV of 88%, 87%, 76%, and 94%, respectively. For all graders, there were statistically significant associations between type 1 MNV and presence of the double-layer sign (P < 0.001). Presence of the double-layer sign on structural OCT B-scans was associated with subclinical type 1 MNV and can be used to identify these lesions with good predictive values in eyes with nonexudative AMD.