“…The amount of birefringence bias is then mathematically removed point by point from the total 1 VST Glaucoma Center, L V Prasad Eye Institute, Hyderabad, India 2 Center for Clinical Epidemiology and Biostatistics, L V Prasad Eye Institute, Hyderabad, India birefringence pattern of the image to improve the signal and obtain a retardation pattern of the RNFL with the least noise. [4][5][6] Though numerous studies have reported good diagnostic ability of both SDOCT [7][8][9][10][11] and GDx ECC 12,13 in glaucoma, there is limited literature on the head-to-head comparison of these imaging techniques in the same population. 14,15 Also, most of these studies have employed a case-control design including glaucoma patients (cases), defined based on the presence of repeatable characteristic glaucomatous visual field (VF) defects; and normal subjects (controls), usually recruited from the general population and having normal intraocular pressures (IOPs), healthy appearance of the optic nerve and normal VFs.…”