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Glaucoma Causes: Can You Prevent This Eye Disease?

Medically reviewed by Victor Paulino, MD, DPBO · Ophthalmology · Makati Medical Center

Written by Hazel Caingcoy · Updated May 21, 2021

Glaucoma Causes: Can You Prevent This Eye Disease?

The exact cause of glaucoma is not yet known. We know glaucoma causes damage to the optic nerve: the nerve responsible for sending signals to the brain for vision. What are some glaucoma causes and the risks? 

Glaucoma Causes

Glaucoma causes vary depending on the type of glaucoma a person has.

Common forms of glaucoma are caused by an increase in the pressure inside the eyeball (intraocular pressure) due to a clog in the eyes’ drainage. In one form of glaucoma, the pressure inside the eye is normal but there is still damage in the optic nerve. 

What Does Glaucoma Vision Look Like?: Understanding Your Condition

What Happens Inside the Eye?

The eyeball is filled with a liquid known as the aqueous humour. This nourishes the eye and also keeps its shape. This liquid is being constantly produced by the ciliary body. As the ciliary body produces aqueous humour, the eye also drains it through a spongy tissue known as the trabecular meshwork. 

Think of your eye as a pipe where water flows in and flows out constantly. In a healthy eye, the rate at which the aqueous humour is being secreted is balanced out by the rate at which it is drained. When a person has a common form of glaucoma, less or no aqueous humour is drained because there is a blockage or disruption in the eyes’ drainage system. This is very similar to when your sink is clogged and water does not have anywhere to go. 

When there is a blockage or disruption in the eye’s drainage system, the fluid inside the eye starts to build up and fill the chambers of the eye that are not normally filled with liquid. When the eye has an abnormal amount of liquid, pressure in the eye increases. 

As the pressure in the eye increases, there will be a decrease in blood flow in the layers of the eye responsible for sending signals to the brain for vision. When the layers of the eye are not getting enough blood flow, they deteriorate, which often results in blurry and dark spots in the visual field.  

Glaucoma and Blindness

Glaucoma has a slow progression. During its early stages, there are hardly any symptoms. When a person notices any changes in their vision, more often than not glaucoma has already reached its advanced stages. 

A very common symptom of glaucoma is blurring or darkening of the side vision or periphery. In more advanced stages, a person starts to see things as if he is going through a tunnel (tunnel vision). Other known complications of glaucoma include light sensitivity, pain in the eye, and blindness. 

Vision impairment and blindness due to glaucoma are irreversible. Depending on the type of glaucoma, early detection and treatment can slow down its progression and prevent complete blindness. People whose glaucoma causes were detected and treated early can carry on living normal lives so long as they follow through with treatment and get regular eye check-ups.

Who is at Risk of Developing Glaucoma?

Everyone is at risk of developing glaucoma but some people have a higher risk of developing the disease.

Family members with glaucoma

Glaucoma is hereditary. If a person has immediate family members who have a history of glaucoma, they have a high chance of also developing the disease. Having a family history of glaucoma increases a person’s risk by four to nine times.

Ethnic background

If a person is African, Hispanic, or Asian, they are likely to develop glaucoma. Asians appear to be at risk of developing angle-closure glaucoma, a rare type of glaucoma that accounts for less than 10% of all glaucoma cases. Japanese people are also at risk of developing another form of rare glaucoma called normal-tension glaucoma.


The older a person gets, the chances of developing glaucoma also increases. Glaucoma is very common in people over the age of 50

Physical injuries in the eye

Getting hit in the eye can result in an immediate increase in eye pressure. Internal damage caused by any trauma in the eye can also increase the progression of developing glaucoma.

Eye conditions

When certain eye conditions alter the anatomy of the eye such as eye tumors or inflammation, this disrupts the drainage system of the eye increasing a person’s risk of developing glaucoma.

Medical conditions

Studies have shown that people with heart disease, high blood pressure, and diabetes are at risk of developing glaucoma. 

Prolonged corticosteroid use

People who have been using medications containing steroids are at risk of developing glaucoma. Examples include pills, creams, and eye drops containing steroids. Asthmatic individuals who use inhalers containing steroids to control their asthma are also more likely to develop glaucoma as they grow older.

Refractive errors

Studies suggest that people with farsightedness or a high level of nearsightedness are likely to develop glaucoma.

Corneal thickness

The cornea is the clear outer layer of the eye covering the pupil and iris, If this layer is too thin, there is a chance that glaucoma will develop. 

How to Prevent Glaucoma: Lifestyle Changes and Tips

Key Takeaways

The true cause of glaucoma is still unknown however we do know that common forms of glaucoma are caused by an increase in the pressure inside the eye.

If glaucoma is not detected and treated immediately, it can result in blindness. The early stages of glaucoma are usually manageable. Treatment can mitigate the effects of glaucoma. Risk factors for glaucoma include age, genetics, and health conditions. 

Learn more about Glaucoma here. 


Hello Health Group does not provide medical advice, diagnosis or treatment.

Medically reviewed by

Victor Paulino, MD, DPBO

Ophthalmology · Makati Medical Center

Written by Hazel Caingcoy · Updated May 21, 2021

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