January is National Glaucoma Awareness Month. It is important to note that people are often unaware of glaucoma until they have lost some or all of their vision, making glaucoma one of the leading causes of irreversible blindness in the United States. So the questions I will answer in this article are: What is glaucoma? How do I know if I have the condition or not? And if I do have it, how is it treated?
Glaucoma is a group of conditions that involve damage to the optic nerve, usually due to elevated intraocular pressure (sometimes normal intraocular pressure), which eventually leads to loss of some or all of the peripheral vision. Intraocular pressure, or the pressure inside the eye, is measured during a routine eye exam. It is measured using a special instrument known as a tonometer — an instrument that may directly touch the eye, or indirectly touch the eye via an air puff. The normal pressure in the eye is usually between 10 and 21 mm of mercury (mmHg); however, some people may have normal pressures with glaucoma and some people may have higher pressures and not have glaucoma.
In addition to the pressure in the eye, the “drainage structure” of the eye is also examined to make sure that the drainage system in the eye is open, narrowed or closed, and that the fluid in the eye can drain from the eye. This is done by first anesthetizing the eye with an eye drop and then examining it with a contact lens that rests on the eye, known as a gonioscopic lens. The lens can help visualize if the drainage system is open, narrowed or closed. This is the difference between open angle glaucoma and narrow angle glaucoma. If the drainage system is narrowed or closed, a laser procedure can be performed in the office to prevent angle closure glaucoma. Angle closure glaucoma is a painful glaucoma attack that can lead to blindness, so prevention is key. Fortunately, angle closure glaucoma is not as common as open angle glaucoma.
Next, the optic nerve in the eye is evaluated to see if the central part of the nerve is normal or enlarged. If this central part of the nerve, known as the cup, is enlarged, then further testing is done such as: visual field testing to check the peripheral vision, photos of the optic nerve are taken, and the nerve fiber layer is checked with a special device called an optical coherence tomography machine (OCT for short).
If you are diagnosed with glaucoma, early intervention is beneficial to slow progression of the disease, although it doesn’t eliminate it. Treatments include: eye drops, laser or surgery. Your eye doctor will determine with you what the best options would be for your type of glaucoma.
I hope I have been able to educate you on glaucoma. Both Dr. John Coco and I welcome you to have your eyes evaluated for glaucoma at Marble Valley Eye care, a part of Rutland Regional Medical Center.
This week’s Health Talk article is written by Dr. Ryan Rogers, ophthalmologist at Marble Valley Eye Care.