Microvasculature Dropout and Development of Normal Tension Glaucoma in Glaucoma Suspects: The Normal Tension Glaucoma Suspect Cohort Study.

PURPOSE:To investigate the contribution of vessel parameters to identify normal tension glaucoma (NTG) suspects at risk of NTG development. DESIGN:Multicenter prospective cohort study. SUBJECTS:A total of 307 eyes of 307 NTG suspects having intraocular pressure within the normal range; a suspicious optic disc, but without definite localized retinal nerve fiber layer (RNFL) defects; and a normal visual field (VF). METHODS:To measure laminar vessel density (VD), the VD was measured in the intradisc region from images of the deep vascular layers of optical coherence tomography angiography (OCT-A). Conversion to NTG was defined either by a new localized RNFL defect in the superotemporal or inferotemporal region, or the presence of a glaucomatous VF defect on 2 consecutive tests according to the pattern deviation plots. MAIN OUTCOME MEASURE:Conversion to NTG. RESULTS:In total, 73 (23.8%) of the 307 NTG suspects converted to NTG during the follow-up period of 59.84 ± 12.44 months. Detection rate of microvasculature dropout (MvD) was significantly higher in NTG suspects who progressed to NTG (50.7%) than in those who did not (6.4%; P < .001). The macular deep VD (P = .006) and laminar deep VD (P = .004) were significantly lower in NTG suspects who progressed to NTG. The presence of MvD (P < .001) and lower laminar deep VD (P = .006) were significantly associated with NTG conversion. CONCLUSIONS:NTG suspects with baseline MvD or a lower laminar deep VD on OCT-A had a higher risk of conversion.