Glaucoma is an eye disease that can damage the optic nerve. The optic nerve supplies visual information to the brain from the eyes. This condition is usually, but not always, the result of abnormally high pressure inside the eye. With time, the increased pressure can erode the tissues of the optic nerve, which may lead to vision loss or even blindness. If it is diagnosed in the early stages, one may be able to prevent additional vision loss. The most common type of glaucoma is primary open-angle glaucoma, and it shows no signs or symptoms except gradual vision loss. The second type of glaucoma is acute-angle closure glaucoma, also known as narrow-angle glaucoma. It is caused due to a medical emergency.

Causes
A clear fluid called aqueous humor is continuously made in the back of the eye. As this fluid is made, it fills the front of the eye. Then, it leaves the eye through the channels in the cornea and iris. In case these channels are blocked or partially obstructed, the natural pressure in the eye, which is called the intraocular pressure (IOP), may increase. The optic nerve may become damaged as the IOP increases. As damage to the nerve progresses, one may begin to lose their vision. One or more factors may play a role in the development of this condition:

• Dilating eye drops
• Blocked or restricted drainage in the eye
• Medications, such as corticosteroids
• Poor flow of blood to the optic nerve
• High or elevated blood pressure

Risk factors

• Age: Age puts a person at an increased risk of developing glaucoma, particularly if they are 60 years or older. The early signs and symptoms of the disease can be identified after one crosses the age of 40.
• Family history: A family history of glaucoma puts a person at a higher risk of developing the disease.
• Elevated eye pressure: As glaucoma is directly related to internal eye pressure, it is essential to keep a check on the eye pressure. It is essential to undergo regular eye checkups to test the pressure.
• Medical conditions: People with diabetes, heart disease, and blood pressure may have an increased risk of developing glaucoma. Both high and low blood pressure increases the risk of this condition.
• Physical injuries to the eyes: Intense and unfortunate injuries may occur if a person is hit in the eye. Critical trauma can lead to the development of high pressure in the eye and may cause internal damage to the optic nerve. A chance of dislocation of lens, increasing pressure, and closing of drainage due to some wounds may also cause this condition.
• Ethnicity: African-Americans or people of African descent are more likely to develop glaucoma than Caucasians. A higher risk of angle-closure glaucoma is present in people of Asian descent, and people of Japanese descent have a relatively higher risk of developing low-tension glaucoma.