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Primary open-angle glaucoma

Primary open-angle glaucoma (POAG), also known as chronic and (simply) open-angle glaucoma, is one of the four main types of glaucoma. And it is a particularly tricky form of the disease because those who have it rarely know anything is wrong until their vision has already deteriorated. 

This is because early stages of primary open-angle glaucoma show no symptoms — no pain, vision loss or other hints that something is amiss, making it a silent thief of sight.

Due to the sneaky nature of this condition and the devastating vision loss primary open-angle glaucoma can cause as it progresses, it’s essential to have regular, comprehensive eye exams. Routine exams give you a leg up on glaucoma by enabling your eye doctor to catch it during early stages before vision damage occurs.

Causes of primary open-angle glaucoma 

Broadly speaking, open-angle glaucoma occurs when fluid within the eye, called intraocular fluid or aqueous humor, gets off balance. 

This intraocular fluid is pumped into the eye from the bloodstream, where it then cleans and nourishes structures inside the eye. Once the fluid flows through it’s inner-eye cycle, it is released back into the bloodstream. 

The process that intraocular fluid performs is critical to maintaining good eye health — it’s circulation keeps everything inside your eyeballs balanced and working smoothly. 

With open-angle glaucoma, the production and drainage of fluid that fills the anterior chamber of the eye (the space between the cornea and the iris) gets off-kilter.

In some cases, too much fluid is produced by the ciliary body inside the eye, which causes an increase in pressure. However, it’s more common for the drainage channels, called trabecular meshwork, where the aqueous exits the eye to become blocked. Whichever cause, the result is that the pressure inside the eye (intraocular pressure or IOP) increases — sometimes to dangerous levels.

As pressure increases, the back of the eye begins pressing on the optic nerve, which (when functioning properly) sends visual information created by the retina to the brain. Continuous pressure on the optic nerve deprives it of oxygen and nutrients, which can cause irreversible nerve damage and vision loss.

SEE RELATED: Narrow-angle glaucoma: Causes, symptoms and treatment

Risk factors for primary open-angle glaucoma

Your risk for glaucoma can be higher based on voluntary and involuntary factors. These risks include:

  • Age — Your risk for developing open-angle glaucoma increases significantly after age 40 and continues to increase with each additional decade. This is, in part, becauses aging can cause drainage channels to shrink or narrow, which slows the outflow of fluid from the eye.

  • Race — Chronic glaucoma in African Americans is five times more common. African Americans are also more likely to develop an aggressive form of the disease at a younger age, making routine eye exams critical for the African American population.

The Glaucoma Research Foundation also lists POAG as the leading cause of blindness in Hispanic Americans and “Latinx” while only 38% of affected “Latinx” are aware that they have the disease. 

  • Certain medical problems — Diabetes raises your risk for chronic open-angle glaucoma. Also, if you have a condition that requires the use of oral or inhaled steroids, particularly if high doses are needed for prolonged periods, this can increase your risk as well.

Other medical conditions that may increase your risk of open-angle glaucoma include headaches, low blood pressure, narrowed blood vessels (vasospasm), cardiovascular disease, and low cerebrospinal fluid pressure (the fluid that bathes the brain and spinal cord).

  • Family history — Your risk of developing open-angle glaucoma may be three to four times higher if one or both of your parents or siblings have the disease.

  • Lifestyle — Research shows smoking, excessive alcohol intake and obesity are big “no-nos” when it comes to glaucoma prevention and your overall health. Keeping an active and healthy lifestyle will lower your risk of open-angle glaucoma and improve your general well-being.

Whether you fall under these high-risk categories or not, getting routine eye exams will make sure you’re not at risk for other forms of glaucoma, or any other conditions that put your eyes at risk. 

SEE RELATED: Glaucoma prevention

Primary open-angle glaucoma treatment options

The whole point of glaucoma treatment — regardless of which type you have — is to lower and stabilize pressure within the eye. This can be achieved with a variety of treatments, from eye drops and medication to glaucoma surgery.

Eye drops

Using eye drops to manage POAG works by promoting more effective eye fluid drainage, or by limiting the amount of fluid within the eye. The downside to using drops for glaucoma treatment is that you typically have to apply them pretty frequently to get the desired effect, which isn’t the most convenient approach.

Oral medication

It’s also possible to take oral medication to effectively lower eye pressure or improve optic nerve health. While this option may seem lower maintenance than using eye drops, medications typically have undesirable side effects and can ultimately cost your more money than the long-term solution of glaucoma surgery.


Glaucoma surgery normally involves using a laser to target tissue in the eye that’s responsible for draining fluid, making it possible for eye pressure to normalize. Although this procedure has proven to be extremely successful and effective, it is not a permanent fix. Results will fade over time (approximately ten years) and another procedure will likely be required.

SEE RELATED: Glaucoma treatment

Unfortunately, when dealing with any type of glaucoma, treatment cannot restore any vision that was lost or damaged along the way — all the more reason to have regular comprehensive eye exams. Your eye doctor will be able to check your eye pressure and suggest preventive measures if you appear to be a glaucoma suspect. 

Glaucoma suspects don’t necessarily have glaucoma, but their eye exam presents some “red flags” to the eye doctor. This little warning sign allows them to start preventive treatment so the condition does not worsen.

ARE YOU A GLAUCOMA SUSPECT? Schedule a comprehensive eye exam with an eye doctor near you, and find out if you’re at risk.

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