Abstract
Purpose: :
To estimate progression rate of visual field (VF) in normal-tension glaucoma (NTG) patients with unstable ocular perfusion pressure (OPP), in terms of affected area (central vs peripheral), over a long-term follow-up period.
Methods: :
One hundred and one eyes of 101 NTG patients followed for more than 4 years (mean follow-up duration, 6.2 years±12.1 months) were included. All participants underwent in-hospital 24 hour measurements of intraocular pressure (IOP) and blood pressure (BP). Participants were categorized into two groups, lower (LMF) and higher (HMF) levels of mean OPP fluctuation. For linear regression analysis, all individual values at each test location of the total deviation plot within the central 10° arc (central mean deviation (MD)) and 10 to 24° arc (peripheral MD) were averaged. Linear regression analysis was performed to explore whether the slopes of the overall, central and peripheral MD over the follow-up period were statistically significant in groups with lower (LMF) and higher (HMF) levels of mean OPP fluctuation. A negative slope with a p value less than 0.05 was considered to be statistically significant, and was taken to reflect progression.
Results: :
The average age and MD at baseline were 54.2±11.9 years and -4.82±5.50dB. Among the 101 eyes, 11 eyes (10.9%) showed progression by overall MD, 15 eyes (14.9%) by central MD, and 12 eyes (11.9%) by peripheral MD regression analysis. Two, 2 and 4 out of 33 eyes in the LMF group progressed by overall, central and peripheral MD, while, 5, 9 and 4 out of 35 eyes in the HMF group progressed by the same criteria; the between-group difference was significant in central MD, not in overall and peripheral MD analysis (p=0.029, 0.235, 0.611). Progression rate of overall and peripheral MD were not different between HMF and LMF group (overall MD:-0.193dB/year vs. -0.160dB/year, p=0.85, peripheral MD: -0.132dB/year vs. -0.147dB/year, p=0.93). However, HMF group showed significant higher rate of progression than LMF group in central MD regression analysis (-0.532dB/year vs. -0.195dB/year, p=0.031).
Conclusions: :
The higher level of OPP fluctuation was significantly associated with higher prevalence and rate of central VF progression.
Keywords: intraocular pressure • visual fields