Hypertension, or high blood pressure that does not respond to treatment, has several ocular manifestations. The retina is one of the "target organs" that are damaged by sustained hypertension. By increasing the blood pressure inside the small blood vessels that involve the eye, damage is caused as these vessels expand or rupture and put pressure on nearby tissue. This tissue does not respond well to this pressure, and permanent damage can occur.

Signs of damage to the eye caused by hypertension include AV nicking and copper or silver wiring, as well as sudden right-angle course changes at crossings.

Copper wire arterioles are those arterioles in which the central light reflex occupies most of the width. Silver wire arterioles are those in which the central light reflex occupies all of the width of the arteriole.

A major aim of treatment is to prevent, limit or reverse such target organ damage. The eye is an organ where damage is easily visible at an early stage, so regular eye examinations are important.