glaucoma and the optic nerve

A visual comparison of a healthy optic nerve (right) vs a glaucomatous optic nerve (left)

What does glaucoma look like?

Glaucoma can be hard to describe, because there are no symptoms early on and nothing to “look out for.” So visuals like the one above are very helpful! 

The round structure there is the optic nerve (aka cranial nerve II). The optic nerve is basically like a cable, made of about 1 million nerve fibers, that sends visual information from the retina (the tissue that lines the back of the eye) to the brain.

What we see when we look at the back of the eye is the optic nerve head. I often describe what we’re looking at as a donut. With glaucoma, the nerve fibers of the optic nerve become damaged and the rim tissue (the donut) gets progressively thinner and thinner, leaving a larger cup (the donut hole). This causes permanent loss of vision, beginning peripherally.

The way your optic nerves look is one piece of the glaucoma puzzle. In addition to directly evaluating the optic nerve, there are scans that can be used to image the optic nerve and further assess its structure. These scans (the most prevalent of which is the OCT) give information on the amount of optic nerve tissue loss and the rate of nerve fiber thinning. Visual fields also help show how the optic nerve is functioning by testing your peripheral vision. Beyond the structure and function of the optic nerve, your eye doctor also checks your eye pressure, and evaluates an area of the front part of your eye called the angle. He/she also takes into consideration other risk factors like your age, your race, your family history, and your corneal thickness. 

For more glaucoma info, check out this previous post.

CliffsNotes: Don't let glaucoma eat your donut. Have regular dilated eye exams to know if you are at risk!