Glaucoma is an eye condition that tends to affect mostly the elderly. It’s caused by fluid build-up in the eye which ends up damaging the optic nerve. This leads to progressive loss of vision.

While there is no treatment for glaucoma, you can slow it down and prevent more damage. The good news is that regular check-ups can help catch it early.

Here’s all you need to know about the main types of glaucoma, its causes and early warning signs, as well as treatment options.

What Is Glaucoma

Glaucoma is a progressive disease in which the optic nerve is damaged by increased eye pressure. The eye’s drainage system starts to malfunction, and the accumulated fluid puts pressure on the optic nerve, which becomes irreversibly damaged little by little.

The condition usually affects both eyes, but it might be that one of them is more damaged than the other.

You won’t notice any changes at first, and by the time enough portions of the optic nerve have died, the damage will be quite extensive. Glaucoma is the main cause of blindness for white people over the age of 60.

Black and Hispanic people over the age of 40 are also more at risk of developing glaucoma.

What Causes Glaucoma

To understand what causes glaucoma, we have to look at how the eyes work. The front part of the eye is filled with a liquid called the aqueous humor, whose role is to nourish the tissue and keep the eye inflated, giving it its round shape.

The eye constantly produces this fluid, so it needs to be drained at some point. Glaucoma appears when something goes wrong with the drainage mechanism. Doctors call it the drainage angle, and just like a pipe, it can get clogged.

Any problem with this drainage angle leads to the accumulation of fluid in the eye and causes intraocular pressure (IOP), which affects the optic nerve. The optic nerve serves an essential function as it transmits the images your eyes register to the brain, which decodes them, essentially telling you what it is you’re seeing.

If the nerve is affected, the brain doesn’t get enough information, and you don’t see so well anymore.

The optic nerve is made of over 1 million nerve fibers, and it’s basically these tiny fibers that get damaged by IOP.

Types of Glaucoma

Glaucoma is not just one disease but a group of similar conditions that cause damage to the optic nerve. Let’s have a look at the main types of glaucoma.

Primary Open-Angle Glaucoma

Primary open-angle glaucoma, also known as chronic glaucoma, is the most common form of glaucoma. It’s also the most dangerous as it develops slowly over many years.

It’s caused by partial clogging in the drainage angle, formed by the cornea and the iris of the eye. The changes in vision occur so slowly most people won’t notice the damage. There is no pain or other clear symptom indicating you have a problem.

Closed-Angle Glaucoma

Doctors also refer to this condition as angle-closure glaucoma. It’s caused by the iris bulging and closing the drainage angle, leading to fluid buildup in the eye. Some people have the iris too close to the drainage angle, and this puts them at risk for closed-angle glaucoma.

Closed-angle glaucoma can be acute or chronic. Acute closed-angle glaucoma starts suddenly and is a medical emergency that should send you to the doctor right away. The chronic type of closed-angle glaucoma develops slowly, but the consequences are equally serious.

senior man looking out at the sea with book in hand

Normal-Tension Glaucoma

This is a subtle type of glaucoma, but fortunately not that common. In this case, it’s not the intraocular pressure that causes damage to the optic nerve. If you go to the doctor, your IOP will appear normal.

Experts aren’t very sure what causes normal-tension glaucoma. The assumption is that the optic nerve of people with this condition is more sensitive, so it’s easily damaged even under normal pressure conditions.

The damage might also be caused by decreased blood flow to the optic nerve. One of the main causes of decreased blood supply is atherosclerosis, the buildup of fatty deposits on the walls of the arteries.

Pigmentary Glaucoma

The iris is filled with pigment, which determines the color of your eyes. When the pigment cells start rubbing off the back of the iris, this is called pigmentary dispersion syndrome. These loose pigment cells end up clogging the drainage angle, which causes pigmentary glaucoma.

Congenital Glaucoma

Infants and small children can also develop glaucoma, and in this case, the problem is an anomaly of their eyes that blocks the drainage angle.

Glaucoma Symptoms

In most cases, glaucoma is discovered during a routine eye check-up. There are few signs letting you know you have a problem, but that doesn’t mean there are no symptoms. Symptoms differ depending on the type of glaucoma.

Open-Angle Glaucoma Symptoms

This is the trickiest type of glaucoma because the symptoms are so subtle they are easy to miss. Yet, if you experience loss of peripheral vision, or the ability to see out of the corner of your eyes without having to turn your head, you may want to schedule a visit to the ophthalmologist.

Closed-Angle Glaucoma Symptoms

Chronic closed-angle glaucoma gives you little warning, but you will surely notice an acute episode. Here are the main symptoms:

  • Sharp eye pain, which may also affect the forehead
  • Headache
  • Blurry vision/decreased vision
  • Eye redness
  • Seeing halos or rainbows, especially around lights
  • Nausea and vomiting

Normal-Tension Glaucoma Symptoms

As this is a type of glaucoma that progresses slowly, the symptoms are easy to miss. If you notice blind spots or dark spots in your field of vision, you should go for an eye test. Also, watch out for peripheral vision loss.

Congenital Glaucoma Symptoms

Small infants cannot tell you anything about their vision. Still, a doctor can pick up when something is wrong because in most cases children born with this condition have abnormally large eyes. They might also present excessive tearing or cloudiness of the cornea.

Glaucoma Tests

Experts say that if you’re over the age of 55, you should have an eye test every year. This refers to a dilated eye examination, when the optometrist puts some drops in your eye before running the test.

  • Intraocular pressure tests (tonometry) can tell if you have high IOP, which is one of the main signs of glaucoma.
  • Perimetry tests measure your peripheral vision. The doctor will shine a light at various points of your visual field to detect any loss of peripheral vision.
  • Gonioscopy is one of the most important tests used to diagnose glaucoma. Doctors often use eye drops to numb the eye and then use a special device to examine the drainage angle and see if it’s closed or obstructed.

eye tests performed on elderly person

Good to know: Age-proofing your vision may help you reduce the risk of developing glaucoma. 

Glaucoma Treatment

If the tests show you have glaucoma, you need to act fast to prevent further damage to your eyesight. Here are the most common treatment options.


In most cases, the doctor will give you eye drops to lower the eye pressure. You will have to apply these daily to help eliminate excess fluids from your eyes and keep the pressure in check.

You will also have to go to regular check-ups so the doctor can monitor if the eye drops are enough to prevent further destruction of the optic nerve.

There are various types of eye drops used to treat glaucoma, such as prostaglandins, carbonic anhydrase inhibitors, cholinergic agents, or beta blockers. Some of these eye drops may contain preservatives and other additives, so it’s important not to overuse them.

Glaucoma Surgery

If the medication is not enough to prevent optic nerve damage or if you cannot tolerate the eye drops, your doctor will probably recommend surgery. There are two main types of surgery used to treat glaucoma eyes.

Laser Surgery

This can be done in the doctor’s office and has a short recovery time.

  • Trabeculoplasty is a type of surgery used to treat open-angle glaucoma. A laser is used to clear the clogging in the trabecular mesh of the drainage angle. Once the clogging is eliminated, this will improve fluid drainage and reduce IOP.
  • Iridotomy is usually performed when you experience an acute episode of closed-angle glaucoma. During the procedure, a laser is used to make a tiny hole in the iris, which allows fluids to move through to the drainage angle.

eye check laser surgery

Operating Room Surgery

Traditional surgery is required when the doctor needs to open up the drainage angle. Your doctor might recommend a trabeculotomy. This is necessary when the trabecular mesh is compromised and no amount of unclogging will restore normal fluid drainage.

The surgery will effectively create a new drainage system. Trabeculotomy is often used to treat congenital glaucoma.

In some cases, you might be fitted with a draining device. This is a tiny tube inserted in the eye to direct excess fluids to a reservoir under the conjunctiva. The fluids in the reservoir will be absorbed in the blood vessels.

Living with Glaucoma

Glaucoma is often called the sneaky thief of sight as it doesn’t give you any warning. But seeing an eye doctor regularly and getting tested makes it easier to catch it early.

If you already have glaucoma, lifestyle changes and good nutrition can help you manage the condition better. While these don’t replace medical treatments, they may reduce your eye pressure and slow the progression of the condition.

  • Eat fruits and vegetables high in carotenoids and vitamin A and vitamin C as recent studies indicate these to be helpful.
  • Eat berries and other fruits high in antioxidants as these may help preserve the optic nerve.
  • Exercise regularly to improve blood flow to the eyes and maintain your IOP within healthy levels.
  • Maintain a normal BMI.
  • Avoid stress or engage in activities like yoga that enable you to manage stress better. Stress is a risk factor for higher IOP.
  • Maintain good dental hygiene as certain gum diseases may increase the risk for certain types of glaucoma.

Take the Dry Eyes Test

Dry eyes and glaucoma often go together. As many as 60% of glaucoma patients also have dry eyes.

According to the Glaucoma Foundation, one of the reasons for this is the long-term use of pressure-lowering eye drops. These contain benzalkonium chloride, a preservative that can damage the surface of the eyes, causing dry eyes.

Unlike glaucoma, dry eye syndrome is often easier to treat—provided you become aware of it and don’t neglect the early symptoms. We've written a post on the difference between dry eye and glaucoma.

Are you experiencing any symptoms of dry eyes? A quick 3-minute test can tell you whether you may have dry eye syndrome.

Take the Dry Eye Test.

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