Glaucoma is a group of eye disorders characterized by damage to the optic nerve that leads to a progressive loss of peripheral vision that can culminate in blindness. According to WHO surveys this disabling condition accounts for approximately 2% of visual impairment cases and is the third cause of blindness worldwide (8% of cases). In 2010, OAG accounted for approximately 80% of worldwide glaucoma cases and affected to 44.7 million people of whom 4.5 million will become bilaterally blind.
The eyes receive light signals from the environment. These signals are transmitted through the optic nerve to the brain where images are created. This requires all ocular structures involved in the transmission of light are in a proper place and receive an adequate supply of oxygen and nutrients. Eye tissues achieve this through the production, accumulation and circulation of a crystalline liquid called aqueous humor. The aqueous humor fills the eye distributing nutrients and provides the necessary rigidity to maintain its size and shape.
Intraocular pressure is the pressure exerted by the aqueous humor within the eyeball. Any imbalance in production and drainage of this fluid inevitably causes abnormal intraocular pressure. For example, if there is an insufficient drainage, the intraocular pressure will increase above normal levels due to excessive accumulation of aqueous humor in the eyeball. An abnormally high pressure causes progressive death or degeneration of ocular tissues such as those of the optic nerve leading to partial or complete blindness; this is what happens in glaucoma.
Usually glaucoma is not associated to any alarming symptom such as pain that drives patients to seek early medical attention. This disease progresses silently at a slow pace. In its early stages it only affects to peripheral vision but as it advances visual acuity diminishes even to the extent to cause blindness if remains untreated. As it usually develops without symptoms or visual complaints until late in the disease course, early diagnosis is critical to prevent permanent optic nerve degeneration and therefore irreversible visual loss. Currently there is no cure for glaucoma. However, there are some available pharmacological and surgical approaches to stop its progression.