Purpose: To investigate the prognostic factors responsible for the progression of visual field defects (VFDs) in patients with normal-tension glaucoma (NTG) treated with topical antiglaucoma medications.
Patients and methods: A total of 92 eyes in 92 NTG patients treated with only topical antiglaucoma medications for ≥ 5 years were retrospectively analyzed. To identify subfield-based prognostic factors, the central 30-degree visual field (Humphrey Field Analyzer) was divided into 6 subfields: upper and lower arcuate, paracentral, and cecocentral subfields. Factors related to subfield-based progression (age, refraction, mean intraocular pressure (IOP), IOP variability, central corneal thickness, and disc hemorrhage) were evaluated using a linear mixed model.
Results: Ninety-two eyes in 92 NTG patients were included in this study. The mean observation period was 7.7 ± 2.7 (5.0 to 15.5) years, and the estimated rate of change in the mean deviation value was -0.16 ± 0.31 dB/y (P<0.001). A subfield-based linear mixed model analysis of the time course of changes in the mean of total deviation identified a greater extent of myopia as a significant positive prognostic factor for VFD progression in the upper paracentral area (P=0.016). The mean IOP, central corneal thickness, disc hemorrhage, age, and IOP variation showed no significant contribution in any of the subfields.
Conclusions: The extent of myopia was found to be a significant positive prognostic factor for VFD progression in the upper paracentral subfield for non-high-myopic NTG eyes with an average IOP of 14.2 mm Hg under topical antiglaucoma medication.