Glaucoma Open Angle

5 min read

Glaucoma that has an open angle, more commonly referred to as Open Angle Glaucoma, is the most common type of glaucoma. Primary Open Angle Glaucoma, abbreviated POAG, affects around 68 million people in the world! The following people are at greater risk for this type of glaucoma: Older individuals, Blacks, African-American, Hispanics, and people who have a history of sleep apnea (1-3). The first step in treating Open Angle Glaucoma is either eye drops or SLT laser by an ophthalmologist.

What Is Glaucoma?

Glaucoma is a disease of the optic nerve. The optic nerve is a cranial nerve that connects your brain to your eye, and allows you to see. While glaucoma is affected by high pressure in the eye, there are also types of glaucoma in which the eye pressure is normal. It is important to note that eye pressure is not necessarily related to blood pressure. Patients often think that if they have high blood pressure, they will have high eye pressure. This is not true. 

Glaucoma Open Angle Vs. Closed Angle

There are many different types of glaucoma but two of the broad categories of glaucoma include open angle glaucoma and closed angle, or narrow angle, glaucoma. These two terms refer to the shape and configuration of the drainage system of the eye. The drainage system of the eye is found in the anatomic angle of the eye, hence the names “open angle” and “narrow angle.” When a patient has open angle glaucoma, their eye pressure is high despite the drainage system being anatomically “open.” When someone has narrow angle glaucoma, it is the shape and configuration of the drainage system, or angle, that is contributing to the patient having high pressure in the eye.

The eye is a dynamic structure that is filled with fluid called aqueous. This fluid is constantly being cycled in and out of the eye through the angle of the eye. In open angle glaucoma, the “back-up” of fluid typically happens in the small microscopic structures that are beyond the angle. In narrow angle, the shape of the drainage system itself is contributing to high pressures. There is also an entity called normotensive glaucoma in which the eye pressure is not particularly high, but damage to the optic nerve is still happening. 

Glaucoma Open Angle Testing

In order to figure out what type of glaucoma you have, your doctor will do a series of tests and exams. Some of these exams will be at a microscope called a slit lamp. A gonioscopy lens is used by your ophthalmologist to view the angle of your eye to see if it is narrow or open. Your doctor may also use certain machines to take images of your optic nerve. 

No matter which type of glaucoma you have, you will have to take a visual field test. This test measures your peripheral vision. Glaucoma typically causes loss of a person’s side vision or peripheral vision. It is important to pay attention closely and take this test to the best of your ability for accurate results. Both patients with diagnosed glaucoma and suspected glaucoma have to take visual field tests. If you already have a diagnosis of glaucoma you will typically take a visual field test more often than someone who is just a glaucoma suspect. 

Open Angle Glaucoma Treatment

There are several treatment options for open angle glaucoma. Typically, the patient is offered eye drops or laser by their ophthalmologist. In some states, an optometrist may be able to prescribe eye drops, but laser surgery for glaucoma is best handled by an ophthalmologist who has gone to medical school, and has had surgical training in residency to perform eye lasers. If you or your family member has glaucoma, consider also seeing a fellowship trained glaucoma specialist once a year. Depending on the severity of your glaucoma, you may or may not need a glaucoma specialist. Most general ophthalmologists are capable of managing early to moderate glaucoma, but if it becomes more severe, usually a glaucoma specialist is consulted for their opinion. 

Glaucoma Open Angle Eye Doctor Visit Frequency

If your doctor has told you that you are a glaucoma suspect, you will likely have to see the eye doctor once every six months. If your pressure is high, or your corneas are thin, or if you have other risk factors like a strong family history, the ophthalmologist may ask to see you at 4 month intervals. If you have already been started on treatment for glaucoma, you will usually see the doctor every 4 months or every 6 months. Some glaucoma suspects who are very low risk can be followed on a yearly basis. Glaucoma is not a straightforward disease and there are many factors that play into how often a patient should be followed and tested. 

Sources:

  1. Zhang, N., Wang, J., Li, Y. et al. Prevalence of primary open angle glaucoma in the last 20 years: a meta-analysis and systematic review. Sci Rep 11, 13762 (2021). https://doi.org/10.1038/s41598-021-92971-w
  2. https://jamanetwork.com/journals/jamanetworkopen/article-abstract/2779939
  3. Steven J. Gedde, Kateki Vinod, Martha M. Wright, Kelly W. Muir, John T. Lind, Philip P. Chen, Tianjing Li, Steven L. Mansberger, Primary Open-Angle Glaucoma Preferred Practice Pattern®, Ophthalmology, Volume 128, Issue 1, 2021, Pages P71-P150, ISSN 0161-6420

https://doi.org/10.1016/j.ophtha.2020.10.022

https://www.aaojournal.org/article/S0161-6420(20)31024-1/fulltext

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