How does open-angle glaucoma damage the optic nerve?

Silently: Glaucoma is a disorder that involves damage to the optic nerve a reduction in blood flow; potentially permanent in not treated. In the open-angle type of glaucoma [about 90% of all cases of glaucoma], this damage occurs slowly over time; most patients may not even appreciate a loss of their vision as the damage is that insidious. There is typically no pain associated with this type of glaucoma.

Slowly over time: Typically open angle glaucoma causes loss of ganglion cells with progressive thinning of the retinal nerve fiber layer faster than age-related loss slowly over time (thus generally asymptomatic), eventually leading to an enlarged optic nerve cup seen on eye exam. The optic nerve appears pale with loss of tissue and remodeled laminar changes.