Glaucoma has been a leading cause of blindness among people who are 60 years or above. Although it can occur at any age, it has been observed to be more common among older adults. Comprising of a group of several eye conditions, glaucoma causes damage to the optic nerve. The damage is a result of the eye being subjected to abnormally excess pressure. The optic nerve is quite important for a good vision.

Most forms of glaucoma are progressive and begin with no early warning signs or symptoms. A person with glaucoma does not experience any change in vision until an advanced stage is reached. There is an extremely gradual change in the vision. Moreover, it is not possible to recover from vision loss caused by glaucoma. This is why it is important to undergo regular eye examinations.

The eye examinations for glaucoma should include measurements of eye pressure. This will help in early diagnosis and appropriate treatment to slow down the progress of glaucoma. Treatments are usually given for the rest of the patient’s life since there is no permanent cure for this disorder.

Read on to know more about the various types of glaucoma, its symptoms, and risk factors.

Types of glaucoma

• Open-angle glaucoma : This is the most common form of glaucoma. In this, the drainage angle that is formed between the cornea and iris remains open. However, there is a partial blockage in the trabecular meshwork. This exerts pressure in the eye, which gradually increases over time. This damages the optic nerve.
• Angle-closure glaucoma : Also known as closed-angle glaucoma, this happens when the iris bulges out, causing a blockage in the drainage angle that is formed by the iris and the cornea. Due to this, the fluid in the eye is unable to circulate, which increases the pressure exerted on the eye. This may happen over time or suddenly as well. It can be a medical emergency if it is acute angle-closure glaucoma.
• Normal-tension glaucoma : In this condition, the eye pressure is in the normal range, and yet, there is damage in the optic nerve. This may happen if the optic nerve is sensitive or if there is less blood flowing to the optic nerve.
• Pigmentary glaucoma : There is a build up in the drainage channels due to the flow of pigment granules from the iris. This slows down or blocks the fluid exiting from the eye. Certain activities such as jogging may sometime move the pigment granules and cause them to accumulate on the trabecular meshwork. This may exert pressure on the eye, leading to pigmentary glaucoma.

Symptoms
Based on the type and stage of glaucoma, the symptoms and signs of the disease will be different. The common symptoms of open-angle glaucoma include patchy blind spots in the peripheral or central vision. This may happen frequently in both the eyes. Another common symptom is tunnel vision. This usually occurs during the advanced stage of glaucoma.

Acute angle-closure glaucoma symptoms include a severe headache, eye pain, nausea, vomiting, blurred vision, redness in the eyes, and seeing halos around lights.

Risk factors
Some people are at high risk of glaucoma. Some of the known risk factors include a family history of glaucoma, nearsightedness, farsightedness, eye injury, eye surgery, intake of corticosteroids in the form of eyedrops, thin corneas, and intraocular pressure.