Optic Nerve Tortuosity and Globe Proptosis in Normal and Glaucoma Subjects.
Wang Xiaofei, Rumpel Helmut, Baskaran Mani, Tun Tin A, Strouthidis Nicholas, Perera Shamira A, Nongpiur Monisha E, Lim Winston E H, Aung Tin, Milea Dan
AI Summary
Glaucoma patients showed tauter optic nerves during eye movements and more protruding globes than normal subjects, suggesting increased optic nerve head stress in anatomically predisposed individuals.
Abstract
Unlabelled: PRéCIS:: Eyes with glaucoma have tauter optic nerves compared with normal eyes, which may exert more force on the optic nerve head tissues during eye movements.
Purpose
The purpose of this study was to assess the difference in optic nerve tortuosity during eye movements and globe proptosis between primary open angle glaucoma and normal subjects using orbital magnetic resonance imaging (MRI).
Methods
Ten Chinese subjects matched for ethnicity and refractive errors were recruited, including 5 normal controls and 5 patients with primary open angle glaucoma. All subjects underwent MRI to assess their optic nerves and globes for 3 eye positions: primary gaze, adduction, and abduction. Optic nerve tortuosity (optic nerve length divided by the distance between 2 ends) and globe proptosis (maximum distance between the cornea and interzygomatic line) were measured from MRI images.
Results
In adduction, the tortuosity of normal eyes was significantly larger than that of the glaucomatous eyes. Optic nerve tortuosity in adduction in the control and glaucoma groups were 1.004±0.003 (mean±SD) and 1.001±0.001, respectively (P=0.037). Globe proptosis (primary gaze) in glaucoma subjects (19.14±2.11 mm) was significantly higher than that in control subjects (15.32±2.79 mm; P=0.046).
Conclusions
In this sample, subjects with glaucoma exhibited tauter optic nerves and more protruding eye globes compared with normal eyes. This may impact optic nerve head deformations in anatomically predisposed patients.
MeSH Terms
Shields Classification
Key Concepts4
The optic nerve tortuosity in adduction in normal eyes was significantly larger than that of glaucomatous eyes, with values of 1.004±0.003 (mean±SD) for normal eyes and 1.001±0.001 for glaucomatous eyes (P=0.037).
Globe proptosis in primary gaze was significantly higher in glaucoma subjects (19.14±2.11 mm) compared to control subjects (15.32±2.79 mm; P=0.046).
Eyes with glaucoma exhibited tauter optic nerves and more protruding eye globes compared with normal eyes, which may impact optic nerve head deformations in anatomically predisposed patients.
Orbital magnetic resonance imaging (MRI) was used to assess optic nerves and globes for 3 eye positions (primary gaze, adduction, and abduction) in 10 Chinese subjects (5 normal controls and 5 patients with primary open angle glaucoma) matched for ethnicity and refractive errors.
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