Progressive optic nerve damage (glaucomatous or nonglaucomatous) is associated with focal narrowing of the retinal arterioles and is proportional to the stage of the optic neuropathy.^1,2,3 Retinal arteriole narrowing is characteristic of, but not always specific for, glaucoma.⁴

Regarding glaucomatous optic nerve damage in all forms, the focal narrowing of the retinal arterioles is associated with decreased neuroretinal rim area, decreased retinal nerve fiber layer (RNFL) visibility, and increased associated visual field defects.⁴ This vessel diameter narrowing may be due to autoregulation from decreased vascular demand in the superficial layers of the retina, and/or overall decreased optic nerve vascular perfusion (vascular insufficiency) common in patients with glaucoma.^4,5,6