Untreated glaucoma can lead to the faster development of permanent vision loss or blindness. Unfortunately, the reality is that glaucoma is a leading cause of irreversible blindness in the world.

Any vision lost as a result of glaucoma is permanent. For this reason, early detection, diagnosis and treatment is essential to preserve your long-term eyesight. However, since many forms of glaucoma have little to no warning signs, regular comprehensive eye exams are absolutely crucial. The vast majority of cases of glaucoma are picked up at these appointments, enabling patients to get the rapid professional support that they need to prevent permanent damage to their vision.

There are several types of glaucoma, including:

• Open-angle glaucoma. This type is the most common, affecting up to 90% of patients who have glaucoma. It occurs when resistance builds up in your eye’s drainage canals. Your drainage canals appear to be open and functioning normally. Over months or years, the fluid in your eye can build up and put pressure on your optic nerve. The disease may go unnoticed for years because most people don’t have symptoms.
• Closed-angle glaucoma. Also called angle-closure or narrow-angle glaucoma, this rare type often comes on suddenly (acute). It occurs when the angle between your iris and cornea is too narrow. It may happen when your pupil changes and becomes too big (dilated) too quickly. This blocks your drainage canals and prevents aqueous fluid from leaving your eye, causing eye pressure to rise. Symptoms, including eye pain and headaches, can be severe and require immediate medical attention.
• Normal-tension glaucoma. As many as 1 in 3 people have optic nerve damage even when eye pressure is normal or not very high. Experts are uncertain about what causes normal-tension glaucoma. Another name for this type is normal-pressure or low-tension glaucoma. This type is more common among people of Asian descent or Asian Americans.
• Congenital glaucoma. Some babies are born with drainage canals that don’t form properly in the womb. Your healthcare provider might notice your baby’s glaucoma symptoms at birth or signs may become noticeable during childhood. Other names for this type are childhood, infantile or pediatric glaucoma.

Glaucoma can occur without any cause, but many factors can affect it. The most important of these factors is intra-ocular eye pressure. Your eyes produce a fluid called aqueous humor that nourishes them. This liquid flows through your pupil to the front of your eye. In a healthy eye, the fluid leaves through the drainage canals located between your iris and cornea.

With glaucoma, the resistance increases in your drainage canals. The fluid has nowhere to go, so it builds up in your eye. This excess fluid puts pressure on your eye. Eventually, this elevated eye pressure can damage your optic nerve and lead to glaucoma.

What are risk factors for glaucoma?

Glaucoma can affect anyone, but the risk increases with age. People who are Black and Hispanic are much more likely to get glaucoma than other ethnic groups, and they tend to develop the disease earlier in life. Asian and Inuit populations are also more susceptible to a specific form of glaucoma known as angle-closure glaucoma or closed-angle glaucoma.

People with diabetes are twice as likely to get glaucoma. Other risk factors include:

• Family history of glaucoma.
• Farsightedness or hyperopia (for closed-angle glaucoma).
• High blood pressure (hypertension and very low blood pressure (hypotension)
• Long-term use of corticosteroids.
• Nearsightedness or myopia (for open-angle glaucoma).
• Previous eye injury or surgery.

People want to know what the early warning symptoms of glaucoma are. The problem is that for some types of glaucoma, there aren’t any early warning symptoms, and changes to vision can happen gradually, so the symptoms are easy to miss. Because many people with open-angle glaucoma don’t have any noticeable symptoms, it’s very important to have routine eye exams to detect this disease in its earlier stages. Glaucoma damage is irreversible, so you need early detection and treatment to prevent blindness.

Closed-angle glaucoma has more severe symptoms that tend to come on suddenly.

With any type, you may experience:

• Eye pain or pressure.
• Headaches.
• Rainbow-colored halos around lights.
• Low vision, blurred vision, narrowed vision (tunnel vision) or blind spots.
• Nausea and vomiting.
• Red eyes.

It’s possible to have glaucoma and not know it. Regular eye exams are important to catch glaucoma or other eye problems. Eye exams can assess optic health and vision loss.

To check for glaucoma, an eye doctor may do one or more of these painless tests:

• Dilated eye exam to widen pupils and view your optic nerve at the back of your eyes.
• Gonioscopy to examine the angle where your iris and cornea meet.
• Optical coherence tomography (OCT) to look for changes in your optic nerve that may indicate glaucoma.
• Ocular pressure test (tonometry) to measure eye pressure.
• Pachymetry to measure corneal thickness.
• Slit-lamp exam to examine the inside of your eye with a special microscope called a slit lamp.
• Visual acuity test (eye charts) to check for vision loss.
• Visual field test (perimetry) to check for changes in peripheral vision (your ability to see things off to the side).