The optic nerve head in glaucoma is susceptible to degeneration if blood or oxygen supply is insufficient.

“glaucoma's interesting because the optic nerve where it degenerates kind of right at the head of the optic nerve where it where it exits the eye it's what we call a watershed Zone it's kind of the edge of two blood vessel supplies and if either of those blood vessel supplies are a little bit short on blood or oxygen supply to that optic nerve head your glaucoma is going to get worse your optic nerve is going to be underfed and that's going to worsen this degenerative process just by not having all the right nutrients and oxygen”