"Most treatments for glaucoma are designed to lower and/or control intraocular pressure (IOP), which can damage the optic nerve that transmits visual information to the brain. Glaucoma eye drops often are the first choice over glaucoma surgery and can be very effective at controlling IOP. If your eye doctor feels you are a good candidate for glaucoma eye drops, you may be prescribed more than one type to achieve the best IOP control."
"The signs and symptoms of glaucoma vary depending on the type and stage of your condition. For example:
Open-angle glaucoma - Patchy blind spots in your side (peripheral) or central vision, frequently in both eyes, Tunnel vision in the advanced stages
Acute angle-closure glaucoma - severe headache, eye pain, nausea, blurred vision, eye redness, etc.
Sources - Mayoclinic, All About Vision