Risk Factors of Primary Open-Angle Glaucoma

Yvonne Ou, MD

University of California, San Francisco, UCSF Medical Center

  • Expert Advice
Published on:
A senior African American couple talking with their doctor.

Much of the information about the risk factors for primary open-angle glaucoma are based on population-based studies in which large groups of patients have been examined and followed over time. Learn about these well-described risk factors.


  • Age
  • Intraocular pressure (IOP)
  • Race/ethnicity
  • Family history
  • Myopia (nearsightedness)
  • Thin central cornea thickness

Open-angle glaucoma is a group of glaucomas in which the drainage angle of the eye is in a “wide” or “open-angle” configuration. Primary open-angle glaucoma is a type of open-angle glaucoma where a secondary cause of increased eye pressure, such as chronic steroid use or eye trauma, is not present. This article will focus on the risk factors of primary open-angle glaucoma.


The major risk factor of primary open-angle glaucoma is age. As we get older, the drainage system no longer functions as well, and the eye pressure can gradually increase.

Eye Pressure (Intraocular Pressure)

A second major risk factor, and the only modifiable risk factor, is increased eye pressure. Current treatments for all glaucomas are focused on reducing eye pressure through medications, laser, or surgery. While eye pressure is a major risk factor for primary open-angle glaucoma, there is also a subtype of glaucoma in which eye pressure is not elevated, which some call “normal-tension glaucoma” or “low-tension glaucoma.” However, even in patients who have normal or low pressures, reducing eye pressure also prevents glaucoma from worsening.

Race and Ethnicity

Race and ethnicity are also risk factors for primary open-angle glaucoma. African and Hispanic people have an increased risk of glaucoma. The reasons for this increased risk are not yet definitively known.

Family History

Family history is also a risk factor, especially if first degree relatives such as parents or siblings have glaucoma. Anyone who is diagnosed with glaucoma should advise their first-degree relatives of their diagnosis and encourage family members to have a comprehensive eye exam.

Corneal Thickness

The eye’s anatomy may also influence risk factors for glaucoma. For example, the thickness of the cornea, which is the clear window to the eye, will be measured during a comprehensive eye exam. Patients with thinner corneas may have an increased risk of glaucoma.

Nearsightedness (Myopia)

Patients who have myopia, or nearsightedness, also have increased risk of primary-open angle glaucoma. This may have to do with the fact that the optic disc has a different shape and/or the nerve has increased vulnerability to eye pressure, even when it is in the “normal” range. Patients with an increased “cupping” of their optic nerves are also at increased risk of primary open-angle glaucoma.

Diabetes and Blood Pressure

Diabetic patients or patients with high blood pressure may also have increased risk of primary open-angle glaucoma, although this relationship is not as well-established as the risk factors discussed above. Regardless, good blood sugar and blood pressure control should be a goal of general health and cardiovascular health. On the other hand, overtreated blood pressure or low blood pressure may be considered a risk factor for glaucoma. The health of the eye requires good blood flow to the optic nerve, thus if the blood pressure dips too low, that can also increase the risk of glaucoma.


In summary, there are several risk factors for primary open-angle glaucoma that have been well described. However, ultimately, the diagnosis of glaucoma can only be made through a comprehensive eye exam performed by an ophthalmologist.

About the author

Yvonne Ou, MD

Yvonne Ou, MD

University of California, San Francisco, UCSF Medical Center

Yvonne Ou, MD, is a board certified ophthalmologist who specializes in glaucoma, including medical, laser and surgical therapies; cataract evaluation and treatment including combined cataract and glaucoma surgery; glaucoma filtering and implant surgery; and newer procedures.

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