Spectral-domain Optical Coherence Tomography Measurement of Macular Volume for Diagnosing Glaucoma

Purpose: To determine the glaucoma diagnostic power of measuring the volume of the ganglion cell complex (GCC; 3 innermost retinal layers) using spectral-domain optical coherence tomography (SD-OCT). Patients and Methods: Fifty eyes with open-angle glaucoma and 35 normal partipants were included for this study. SD-OCT (RTVue-100), and time-domain (TD)-OCT were used to measure total retinal, GCC (SD-OCT only), and circumpapillary retinal nerve fiber layer (cpRNFL) thicknesses in 50 eyes with open-angle glaucoma and in 35 without glaucoma. Results: Total retinal and GCC volumes in a macular area correlated with visual field mean deviation (GCC: r=0.580, P<0.001; total: r=0.458, P<0.001). The area under the receiver operating characteristic curve (AROC) was greater for macular GCC volume (0.922) than for macular total retinal volume, as measured by SD-OCT (0.857; P=0.020) or TD-OCT (0.841; P=0.025). GCC AROCs were smaller than cpRNFL AROCs determined using SD-OCT (0.971; P=0.110) or TD-OCT (0.970; P=0.122), but not in a statistically significant manner. AROC for the GCC was greatest in the inferior macula. Interclass correlation coefficient values were comparable for GCC and total retinal volumes. Conclusion: Selective measurement of the GCC layer by SD-OCT improves diagnostic performance of the macular structural analysis for glaucoma diagnosis.