Glaucoma is a term used to refer to a group of eye diseases that ultimately cause damage to the optic nerve. Unfortunately, there is no cure for glaucoma; but there are treatments available to help manage the condition and prevent vision loss. People with glaucoma often experience slow and gradual vision loss that is so subtle, it is virtually undetectable until it reaches advanced stages. Glaucoma often presents no other symptoms than vision loss, which is why it is important to visit your eye doctor periodically for comprehensive eye exams. As the disease progresses, it can cause eye pain and nausea, as well as total vision loss.