Glaucoma occurs when the drainage mechanism within the eye become slightly blocked, this prevents eye fluid from draining properly. When the fluid cannot drain properly, pressure builds up, this is called intraocular pressure. This can damage the optic nerve, which connects the eye to the brain, and the nerve fibers from the retina. If left untreated, glaucoma can cause blindness. But if it is diagnosed and treated early enough, further damage to vision can often be prevented. Most cases of glaucoma are painless and slow to develop although there is a type known as acute closed angle glaucoma that can develop very rapidly and be quite painful and requires immediate medical assessment and treatment. Glaucoma can be treated with eye drops, laser treatment or surgery. However, early diagnosis is important because any damage to the eyes cannot be reversed. Treatment aims to control the condition and minimise any future damage. Attending regular optician appointments will help to ensure that any signs of glaucoma can be detected early and allow treatment to begin. Without treatment, glaucoma can eventually cause blindness.