Images that are seen travel from the eye to the brain via the optic nerve. When this nerve suffers damage, vision can become impaired and glaucoma can appear. According to the Mayo Clinic, this is the second-leading cause of blindness, sometimes called the "silent thief of sight" because it happens gradually.
Open Angle
Primary open-angle glaucoma takes place when the drainage canals in the eye get clogged and the intraocular pressure (eye pressure) increases. Over the course of time, vision becomes impaired but the loss of sight can take many years to be noticed. According to the Glaucoma Research Foundation, this is the most common form of glaucoma and affects nearly three million Americans.
Angle Closure
Angle-closure glaucoma is a more rare and serious type than open-angle, and the effects are very different. Eye pressure rises quickly with this type, and the drainage canals get blocked by the iris bunching up over the top of them. (The iris is the colored part of the eye.) This can lead to pain, visual disturbances in low light, blurred vision and the eyes can become red.
Risks
African-Americans and people older than 60 are the most susceptible for glaucoma. If glaucoma runs in your family, you're at risk of developing it as well. Glaucoma can also result as a secondary condition from high blood pressure, diabetes, eye tumors, nearsightedness and the prolonged use of corticosteroids.
Progression
If glaucoma is left untreated, it can cause a progressive loss of vision in a series of phases. Blind spots can develop in your peripheral vision, the vision that allows you to see to your sides. Tunnel vision is the next phase; that's a complete loss of peripheral vision. The final phase is complete blindness.
Treatments
There is no concrete cure for glaucoma. Treatments aim to reduce pressure in the eyes, promoting aqueous fluid and preventing the loss of vision from worsening. Medicated eye drops are commonly a first line of defense. Examples of these are beta blockers, alpha agonists, prostaglandin-like compounds and epinephrine compounds. Oral medications such as carbonic anhydrase inhibitors and neuroprotective drugs can be used if the eyedrops are not working. In the most severe cases, surgery can be performed to open clogged drainage canals and increase aqueous fluid output.
