Risk Factors for Progression of NTG in Japanese Patients

Journal Highlights

Ophthalmology, August 2019

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Sakata et al. evaluated the history and risk factors associated with progression of normal-tension glaucoma (NTG) in patients who received close follow-up but were not treated. Among their study population, whose mean intraocular pressure (IOP) at baseline was 12.3 mm Hg without treatment, the probability of glaucoma progression within five years was 66%. Significant contributors to progression were long-term fluctuation of IOP, greater vertical cup-to-disc (C/D) ratio, and the presence or history of disc hemorrhage.

For this study, the researchers included 90 Japanese patients with NTG whose IOP had been consistently below 16 mm Hg before study entry, without any glaucoma treatment. During the study, visual fields (VF) were examined at three-month intervals, and disc/peripapillary retinal photographs were obtained every six months. Treatment was not provided during the study. Outcomes of interest were deterioration in VF (defined by established criteria) and the disc/peripapillary retina (judged by three independent observers). Life table analysis was used to estimate the time to disease progression, and risk factors were identified using a Cox proportional hazards model.

The mean age of the study group was 54 years; mean baseline IOP was 12.3 mm Hg; and mean deviation was -2.8 dB. The mean deviation (MD) slope averaged -0.33 dB per year. The probability of glaucoma progression by year 5 was 66% according to VF or disc/peripapillary retinal deterioration (criterion 1), 52% by VF deterioration alone (criterion 2), and 50% by disc/peripapillary retinal deterioration alone (criterion 3).

Significant predictors of progression according to criterion 1 were presence or history of disc hemorrhage (p < .001), long-term IOP fluctuation (p = .020), and greater vertical C/D ratio (p = .018). The latter two factors also were significant predictors of progression according to criterion 2 (p = .011 and .036, respectively). The significant predictors for criterion 3 progression were long-term IOP fluctuation (p = .022) and the presence or history of disc hemorrhage (p = .0018).

The common predictor of progression among all three criteria was long-term fluctuation of IOP. The authors emphasized that the apparent link between fluctuating IOP and progression of NTG may have therapeutic implications. (Also see related commentary by C. Gustavo De Moraes, MD, MPH, in the same issue.)

The original article can be found here.