What are precursors for glaucoma?

Many things: Age, genetics, cup:disc ratio (how optic nerve looks), eye pressure, thickness of the cornea (called pachymetry), ass'd medications (chronic steroids most common), other eye diseases, history of trauma.

Suspicious Exam: Unfortunately, in the most common glaucoma called open angle glaucoma, there are no symptoms until the disease becomes advanced. About half of people with glaucoma are unaware of it. If you have a family history of glaucoma you should have an annual exam. If you are over 40 you should have an exam to evaluate for risk.