Initial central scotomas vs peripheral scotomas in normal-tension glaucoma: clinical characteristics and progression rates

Purpose To investigate clinical characteristics and progression rates of the initial central scotomas (ICS) compared with the initial peripheral scotomas (IPS) in normal-tension glaucoma (NTG) patients. Methods Among NTG patients showing a single hemifield defect and who performed more than five reliable standard visual field (VF) tests, medical records of ICS (involvement of >= 3 adjacent points with P<5% within the central 12 degrees of fixation and one point with a P<0.01 within the central 6 degrees of fixation) (n = 32) or IPS (no VF abnormality within the central 6 degrees of fixation) (n = 34) were retrospectively analyzed. The changes of mean thresholds from 10 zones of the glaucoma hemifield test, central 6 degrees and 12 degrees zones, peripheral zones other than central 6 degrees and 12 degrees, and the entire hemifield were inspected. To calculate the progression rates, linear mixed-effect model was employed. Results There were no significant differences between the two groups in age, gender, ocular factors including baseline/mean treated intraocular pressure, and systemic factors including systolic or diastolic blood pressure/perfusion pressure, mean ocular perfusion pressure (all P>0.05). There were no significant differences in baseline mean deviation and pattern standard deviation (P>0.05) between the two groups, but VF index was significantly lower in ICS group than in IPS group (P = 0.001). The progression rates between the two groups were not significantly different in all zones we investigated (all P>0.05). Conclusions Newly diagnosed cases of NTG with ICS may not differ from those with IPS in clinical characteristics and progression rates under treatment.