Abstract
PURPOSEThe presence of a double layer sign (DLS) and a shallow irregular RPE elevation (SIRE) were investigated using spectral domain-optical coherence tomography (SD-OCT) imaging to determine their ability to predict progression to exudative macular neovascularization (eMNV) in the unaffected fellow eyes (study eye) of participants with Age-Related Macular Degeneration (AMD) with newly diagnosed unilateral eMNV. DESIGNRetrospective, re-analysis of SD-OCT scans of study eyes from the Early detection of Neovascular AMD (EDNA) study with 3 years follow-up (FU). PARTICIPANTSThe EDNA study repository of SD-OCT scans was assessed for inclusion. Cases with incomplete datasets, low quality scans or exhibiting other pathology were excluded, which resulted in 459 eligible cases. METHODSSD-OCT volume scans of study eyes were graded for irregular elevation of the RPE (IE), length and height measurements made on the most affected B-scan. Eyes with heterogeneous reflectivity within the IE were classified as exhibiting the DLS. Eyes with DLS where the length of separation between RPE and Bruch's was equal or exceeded 1000 μm in length and less than 100 μm in height were sub-classified as SIRE. MAIN OUTCOME MEASURESHazard of progression to eMNV for DLS and SIRE RESULTS: Of the 459 eyes, 268 had IE in which 101 were DLS-like and 51 of these also fulfilled criteria for SIRE. Over the 3 years FU period, 104 (23%) eyes progressed to eMNV. After a follow up of 18 months, a significantly higher proportion of study eyes (p<0.001) with IE, DLS and SIRE developed eMNV compared with those without these features (IE: 17% vs no IE 6.3%; DLS: 23% vs no DLS 9.9%; SIRE: 22% vs no SIRE 11%). In the adjusted Cox regression models, a significantly greater hazard of progression (p<0.001) was associated with the presence of IE (adjHR, 3.01, 95%CI 1.88, 4.82), DLS (adjHR, 3.41, 95%CI 2.26, 5.14) or SIRE (adjHR, 2.83, 95%CI 1.68, 4.75). CONCLUSIONThe DLS is a highly sensitive predictor of progression to eMNV and the use of SIRE does not improve predictability.