Glaucoma is a disease of the optic nerve that can lead to irreversible blindness if left uncontrolled. It is often asymptomatic until severe vision loss has occurred. The most common type is primary open-angle glaucoma, which occurs when the eye does not properly drain fluid, leading to elevated pressure in the eye. Treatment aims to lower intraocular pressure through medications, laser treatment, or surgery in order to slow the progression of vision loss. While glaucoma continues progressing even with treatment, the rate of progression is much slower, allowing for satisfactory vision with proper management.