Risk factors for visual field progression of normal-tension glaucoma in patients with myopia

Objective To identify risk factors for visual field progression of normal-tension glaucoma (NTG) in patients with myopia. Design Longitudinal, observational study. Participants Fifty-one eyes of 51 NTG patients with myopia (less than −0.75D based on spherical equivalence) who had undergone visual field (VF) testing at least once per year for ≥6 years between November 2005 and December 2013. Methods Progression was defined using event-based guided progression analysis. Risk factors were analyzed using the Cox proportional hazards model and further tested for independence in a multivariate model. Results The mean observation period was 7.0 ± 1.3 years, and 16 of 51 subjects showed progression. In the univariate analysis, abnormal retinal nerve fibre layer (RNFL) colour codes (yellow or red sector) at the 11, 10, and 7 o'clock positions on optical coherence tomography showed significant associations with the VF progression (p = 0.03, 0.03, and 0.01, respectively). In the final multivariate models, the abnormal RNFL colour code of the 7 o'clock sector (inferotemporal sector) was the only significant risk factor for progression (hazard ratio = 4.07 and 4.37; 95% CI, 1.11–14.92 and 1.27–15.04; p = 0.03 and 0.02, respectively). Conclusions Inferotemporal RNFL thinning could be a risk factor for progression in NTG patients with myopia.