Ahmadi H, et al. - Given that the intrinsically photosensitive retinal ganglion cells (ipRGCs) and sleep quality were impaired in patients with primary open-angle glaucoma (POAG), experts aspired to explore if ipRGCs and sleep quality were also impaired in patients (n = 15) with normal tension glaucoma (NTG) and healthy age-matched controls (n = 17). They conducted pupillometry and sleep quality assessment in patients with NTG and healthy age-matched controls. By Pittsburgh Sleep Quality Index (PSQI) questionnaire, sleep quality was evaluated. According to findings, the PIPR_Late to blue light was significantly decreased in patients with NTG vs healthy individuals, showing impairment of the melanopsin-mediated pupillary pathway. NTG patients showed reduced ipRGC activity vs healthy individuals while no differences in sleep quality were observed.