Association between radiation, glaucoma subtype, and retinal vessel diameter in atomic bomb survivors

Yoshiaki Kiuchi,Katsumasa Itakura,Ayumi Hida,Waka Ohishi,Kyoji Furukawa,Ikuno Takahashi,Masahide Yanagi

doi:10.1038/s41598-019-45049-7

Abstract

We examined the relationship between glaucoma subtype and retinal vascular caliber as markers of ocular circulation. Subjects were Japanese atomic bomb survivors in Hiroshima and Nagasaki. After a screening examination, potential cases were subjected to further definitive examination. The diameters of central retinal artery and vein equivalents (CRAE and CRVE) on digitized retinal photographs were measured using an established method. Generalized linear regression analyses were used to examine the associations among vessel diameters, radiation exposure, and prevalence of glaucoma subtypes among the study subjects. We identified 196 cases of glaucoma (12%) based on optic disc appearance, perimetry results, and other ocular findings. The main subtypes were primary angle-closure glaucoma, primary open-angle glaucoma and normal-tension glaucoma (NTG). NTG was the dominant subtype (78%). NTG was negatively associated with CRAE and CRVE, and positively associated with radiation dose. CRVE was negatively associated with radiation dose and the association was unclear for CRAE. The smaller retinal vessel caliber in NTG patients than in subjects without glaucoma may indicate an association between ocular blood flow and the pathogenesis of NTG. However, significant relationships among vessel calibers, NTG and radiation exposure were not clear.

Highlights

Glaucoma is one of the leading causes of blindness worldwide[1]
We previously reported a correlation between the higher prevalence of normal-tension glaucoma (NTG) and radiation dose in Japanese atomic bomb survivors[13], the specific causal mechanism is unclear
Prior epidemiological studies have shown that radiation exposure at doses >0.5 Gy might be associated with an elevated risk of cardiovascular disease, in atomic bomb survivors[14,15,16]; radiation-related perturbed ocular circulation may be linked with NTG development among people with radiation exposure

Summary

Introduction

Glaucoma is one of the leading causes of blindness worldwide[1]. Typical glaucoma involves elevated intraocular pressure (IOP), which causes damage to structures in and around the optic nerve head; this leads to visual dysfunction[2]. Cumulative evidence shows persistent progression of visual field loss in NTG, despite interventional reduction in IOP6. This may indicate that some factors other than IOP (e.g., insufficient blood supply in relation to systemic and/or retinal vascular disorders) play pivotal roles in glaucomatous optic neuropathy[7,8,9,10,11,12]. The primary objective of this study was to evaluate subtype-specific associations of glaucoma with ocular vessel diameters and other potential risk factors for glaucoma, including radiation dose, among a clinical cohort of atomic bomb survivors

Objectives

Methods

Results

Conclusion