January is National Glaucoma Awareness Month!
Dr. James Crandall
January is National Glaucoma Awareness Month, which makes this a good time to discuss the second leading cause of blindness worldwide.
Glaucoma is an eye disorder defined by damage to the optic nerve that causes loss of peripheral (side) and sometimes central vision. The optic nerve is the structure that sends information from your eye to your brain for processing.
Untreated glaucoma may lead to irreversible blindness. The underlying cause of glaucoma is not known. Anyone at any age can develop glaucoma, but the risk for this disease increases as people grow older. Other risk factors include a family history of glaucoma, African American or Latino heritage, a history of eye trauma, and increased intraocular pressure (the pressure comes from the production of a fluid called aqueous humor inside the eye).
There are two broad categories of glaucoma. They are referred to as either “open angle” or “narrow/closed angle.” In the United States, the open angle category is far more prevalent. In this type of glaucoma, there are no symptoms during disease onset or early progression. People with undiagnosed open angle glaucoma may not become aware of the problem until vision loss is severe. In narrow/closed angle glaucoma, the eye pressure rises suddenly, which is typically accompanied by symptoms including eye pain, headache, nausea, and blurred vision.
In order to determine your risk for glaucoma, you should have a complete (dilated) eye exam. While the optic nerve can usually be examined without dilating the pupils, dilation is preferable to better examine for subtle changes which may be early signs of glaucoma.
During the eye exam, the eye pressure will be measured. If the optic nerve appearance is suspicious for glaucoma and/or the intraocular pressure is elevated, other testing should follow. Typically a visual field will be obtained to look for loss of peripheral vision.
Additionally, a variety of imaging techniques may be employed to assess the structure of the optic nerve in greater detail. Lastly, an examination of the way aqueous humor leaves the eye should be performed to assess your risk for narrow/closed angle glaucoma.
Normal intraocular pressure is between 12 and 21 millimeters of mercury (mmHg). The pressure is generated due to the production of a fluid called aqueous humor inside the eye. Currently, treatment of glaucoma involves either increasing the outflow of aqueous humor or decreasing its production.
The first-line treatment for most cases of newly diagnosed glaucoma is daily eye drops. In select cases, laser surgery may be a reasonable initial treatment. In cases where eye drops and laser surgery are not effective, or if the vision is worsening despite maximum medical treatment, incisional surgery may be performed to lower the intraocular pressure.
It should be noted that approximately 30% of patients with glaucoma never have a documented pressure over 21 mmHg; however, these individuals also benefit from pressure lowering treatment.
Glaucoma is a very treatable condition after the diagnosis is made. Even with aggressive and appropriate treatment, a small percentage of patients will become blind from glaucoma. In my experience, people with the greatest risk for blindness either were told in the past that they had glaucoma but failed to follow up with treatment recommendations, or were people who were examined after they had already lost a significant degree of vision.
If you have not had an eye exam in a number of years, or if you were told in the past that you were at risk for or had glaucoma, I encourage you to use Glaucoma Awareness Month as an incentive to schedule an eye exam.
Dr. James Crandall is a board certified ophthalmologist who completed a post-residency fellowship in the medical and surgical care of patients with glaucoma. Dr. Crandall practices comprehensive ophthalmology and specialized glaucoma care with Asheville Eye Associates. He is a member of the American Academy of Ophthalmology, the American Glaucoma Society, and the Western Carolina Medical Society.