Abstract
Purpose:
To investigate the clinical characteristics and progression rates of the initial central visual field (VF) defect compared with the initial peripheral VF defect in normal tension glaucoma (NTG) patients.
Methods:
Among NTG patients showing a single hemifield defect and who performed more than 5 reliable standard VF tests, medical records of the initial central VF defects (involvement of ≥3 adjacent points with P<5% within the central 12° of fixation, one point with a P < .01 within the central 6° of fixation) (group 1, n=32) or peripheral VF defects (no VF abnormality within the central 6° of fixation) (group 2, n=34) were retrospectively analyzed. The changes of mean thresholds of the 10 zones of the glaucoma hemifield test, central 6° and 12° of fixation, peripheral zones other than central 6° and 12° of fixation, and the entire superior or inferior hemifield were inspected. Linear mixed effect model with unequal random effect variances was employed. Covariates such as age, gender, initial intraocular pressure, mean deviation (MD), pattern standard deviation (PSD), and visual field index (VFI) were controlled.
Results:
There were no significant differences between the two groups in age, gender, follow-up period, ocular factors including baseline/mean treated intraocular pressure, and systemic factors including systolic or diastolic blood pressure/perfusion pressure, mean ocular perfusion pressure (MOPP) (all p>0.05) (MOPP; 91.03±10.24 mmHg in group 1 and 94.91±10.36 mmHg in group 2, p=0.131). There were no significant differences in baseline MD and PSD (p>0.05) but a significant difference in VFI (90.74±6.13 in group 1 and 95.36±4.03 in group 2, p=0.001). The progression rates between the two groups were not significantly different in all zones we investigated (all p>0.05) (for the entire hemifield; -0.606 dB/yr in group 1 and -0.565 dB/yr in group 2).
Conclusions:
Baseline characteristics and the progression rates of the initial central and peripheral VF defect in NTG patients were not significantly different except for the VFI. It is assumed that the pathogenesis of the central and peripheral VF defect may not be different in NTG.
Keywords: 758 visual fields