Fig. (2-6) The curves showing the retinal thickness of young, normal individuals (YNorm), of older, normal individuals (ONorm), of patients with normal tension glaucoma (NTG), of open-angle glaucoma patients with early visual field defects (OAGE) and of open-angle glaucoma patients with advanced visual field defects (OAGA) as measured using an SLT device (blue) and an SLP device (red). Measurements taken from top to bottom at the rim of the optic nerve head and in increasing distances as shown in Fig. (1). The numbers 1-16 on the x-axis mark the temporal superior sector, 17-48 the superior, 49-80 the nasal, 81-112 the inferior, 113-128 the temporal inferior sectors, respectively.