Kim HJ, et al. – The diagnostic performance of layer–by–layer segmented macular ganglion cell complex (GCC) thickness for detecting early glaucoma utilizing spectral–domain optical coherence tomography (SD–OCT) with different macular grids is examined in this study. Large macular grids have generally high discriminating power for the diagnosis of early glaucoma by SD–OCT. The ganglion cell layer (GCL) or GCC thickness in 3 to 6 mm macular grid could be helpful for the identification of early glaucomatous structural loss.