Cup-to-Disc Ratio From Heidelberg Retina Tomograph 3 and High-Definition Optical Coherence Tomography Agrees Poorly With Clinical Assessment

PURPOSE To investigate the agreement of vertical cup-to-disc ratio (VCDR) measured from Heidelberg Retina Tomograph 3 (HRT-3), high-definition optical coherence tomography (HD-OCT), and clinical grading. METHODS A total of 933 consecutive subjects underwent optic nerve head imaging with HRT-3 and HD-OCT during a single visit. The vertical dimensions of the disc and cup were measured by slit-lamp examination using an eyepiece graticule. Bland-Altman plots evaluated the agreement in the VCDR obtained by the 2 instruments and clinical grading. RESULTS We found a significant trend for the difference in VCDR measured clinically and with HRT and HD-OCT (P