University of California, San Francisco, UCSF Medical Center
Learn how age, family history, ethnicity, gender and eye anatomy are related to the risk of developing primary angle-closure glaucoma.
Primary angle-closure glaucoma describes a condition in which the drainage angle of the eye is closed, rather than open. In addition, there is elevated eye pressure and evidence of optic nerve damage.
The eye’s “angle” can be thought of as the angle between the iris and the cornea and is present 360 degrees around the circumference of the eye, although that is an oversimplification. Nevertheless, in the angle one finds the drainage system of the eye, called the trabecular meshwork.
The video below provides a very good representation of the eye's “angle.”
You may hear your eye doctor refer to your eye’s angle. This is the anatomical angle formed between the iris and the cornea. Combined with the trabecular meshwork, the structure below the iris, this forms the drainage canal for fluid inside the eye. Drainage of fluid is critical for maintaining proper pressure inside the eye. When the eye’s angle is narrow, it can limit the outflow of fluids, which causes fluid to back up, increasing pressure in the eye. High eye pressure can damage the optic nerve, causing a condition called glaucoma, which may result in vision loss. This can happen gradually or suddenly. If it occurs suddenly, the eye’s drainage channel becomes completely blocked and pressure rises rapidly. This is an acute angle closure attack and requires immediate attention from a medical professional in order to prevent permanent vision loss. Many people who have narrow angles do not have high pressure or glaucoma; however, narrow angles are a risk factor for angle closure. People with smaller eyes or who are farsighted are more likely to have narrow angles. Depending on the degree of your narrow angle, your doctor may consider you to be a “glaucoma suspect” and as such, may recommend monitoring your eye through regular exams or taking preventative measures to lower your risk of glaucoma. This may include eye drops to lower eye pressure or a procedure called laser iridotomy, which creates another pathway for fluid to drain. Talk to us today to discuss the best option for your eye care.
Let’s look at the risk factors for this eye condition:
If you have a family history of angle closure, you are at increased risk of angle closure yourself. Often, family members are unclear as to the type of glaucoma others in the family have. One clue is that if they have had a laser iridotomy, or a small hole placed in the iris using a laser, then they likely were at risk for angle closure glaucoma.
The risk for angle-closure glaucoma increases as we age. This may be related to several factors, such as the fact that as we get older, our lens thickens. As the lens thickens and forms cataract, the drainage angle further narrows.
Female gender is also a risk factor for primary angle closure glaucoma.
Finally, it is known that several ethnic groups are at increased risk, including those of Chinese, Vietnamese, Pakistani, or Inuit descent.
Additional risk factors for primary angle-closure and primary angle-closure glaucoma are related to the eye’s anatomy. For example, if you are farsighted, often the eye is shorter than average. In a shorter eye, the front of the eye is more “crowded,” and the drainage angle can be narrow. A thick lens, as described above, also narrows the angle because it takes up extra space. Sometimes it is an imbalance in the size of the eye and the lens. For example, a relatively large lens in a relatively short (or small) eye increases the risk of angle closure. Other eye features such as the steepness of corneal curvature are also risk factors. Finally, some people have an anatomical variation called “plateau iris,” which is a risk factor for angle-closure glaucoma. In plateau iris configuration, the iris is oriented in such a way that it looks like a “plateau” and also causes the angle to be more narrow.
A large amount of research continues to be devoted to understanding angle-closure glaucoma, especially to answer the question of who is at most risk for developing primary angle-closure glaucoma and who is at increased risk of having an acute angle closure glaucoma attack. A discussion with your ophthalmologist will help you to decide what is the appropriate monitoring and/or treatment regimen for your eyes.
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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