Relationship between peripheral vasospasm and visual field progression rates in patients with normal-tension glaucoma with low-teen intraocular pressure

Abstract

Purpose To investigate the association between peripheral vasospasm and the visual field (VF) progression rate in patients with normal-tension glaucoma (NTG) with low-teen intraocular pressure (IOP). Methods The finger temperature of 113 NTG patients was measured before and after exposure to ice water using a Temperature gun (cold pressor test). These patients had confirmed VF progression, despite a low-teen IOP during a follow-up period of >5 years. VF progression rates were calculated as the slope of the visual field index (VFI) and mean deviation (MD) over time. Demographic, systemic, and ocular factors and VF progression rates were compared, based on the cold pressor test results. A regression analysis was used to investigate the factors affecting VF progression rates. Results Mean age, initial IOP, mean IOP during the follow-up period, and initial VF MD were 57.1 years, 15.8 mmHg, 12.0 mmHg, and -5.2 dB, respectively. When patients were divided into two groups (less vasospasm and more vasospasm) according to changes in temperature after exposure to ice water, the VF progression rate was significantly faster in the group with more vasospasm. In a multiple regression analysis, older age, worse initial VF MD, and greater decrease in finger temperature after ice water exposure were significantly associated with faster VF progression rates. Conclusion An excessive drop in finger temperature after exposure to ice water was significantly associated with faster VF progression in patients with low-teen NTG. This suggests that the blood flow in the optic nerve head may also be disturbed by peripheral vasospasm, accelerating glaucomatous damage regardless of IOP.