Enhanced Depth Imaging Optical Coherence Tomography of Optic Nerve Head Drusen

Abstract

To assess the value of enhanced depth imaging optical coherence tomography (EDI OCT) in diagnosing and evaluating optic nerve head drusen (ONHD) compared with conventional diagnostic methods. Prospective, comparative, cross-sectional study. Thirty-four patients with clinically visible or suspected ONHD in either eye based on dilated optic disc examination or optic disc stereophotography and without ocular comorbidity. Spectral-domain OCT of the optic nerve head in both conventional (non-EDI) and EDI modes, ultrasound B-scan, and standard automated perimetry were performed on both eyes of all participants. Detection and findings of ONHD between EDI OCT and conventional diagnostic methods. Sixty-eight eyes were clinically classified into 3 groups: 32 eyes with definite ONHD, 25 eyes with suspected ONHD, and 11 normal-appearing fellow eyes. In the definite ONHD group, EDI OCT, non-EDI OCT, and ultrasound B-scan were positive for ONHD in all eyes and visual field (VF) was abnormal in 24 eyes. In the suspected ONHD group, EDI OCT, non-EDI OCT, ultrasound B-scan, and VF were positive in 17, 14, 7, and 3 eyes, respectively; 8 eyes had no evidence of ONHD in any of the tests. In normal-appearing fellow eyes, EDI OCT, non-EDI OCT, ultrasound B-scan, and VF were positive in 3, 1, 1, and 0 eyes, respectively; 4 eyes had no evidence of ONHD in any of the tests. Enhanced depth imaging OCT had a significantly higher ONHD detection rate than ultrasound B-scan in all eyes (52/68 eyes vs. 40/68 eyes; P<0.001), in eyes with clinically suspected ONHD or normal-appearing fellow eyes (20/36 eyes vs. 8/36 eyes; P<0.001), and in eyes with clinically suspected ONHD (17/25 eyes vs. 7/25 eyes; P = 0.002). Enhanced depth imaging OCT-detected ONHD appeared as signal-poor regions surrounded by short, hyper-reflective bands or isolated/clustered hyper-reflective bands without a signal-poor core. In non-EDI OCT, posterior surfaces of the ONHD and deep-seated hyper-reflective bands were invisible or less clear than in EDI OCT. Enhanced depth imaging OCT detects lesions likely representing ONHD more often and better assesses their shape and structure than conventional tests.