The optic nerve is what transmits visual data from the eye to the brain.
When the optic nerve is damaged, our vision suffers. A group of conditions that threaten the optic nerve is glaucoma. In the United States, glaucoma is the second most common cause of vision loss and blindness, affecting three million people. Because January is National Glaucoma Awareness Month, we wanted to give our patients a basic understanding of the condition.
The Internal Pressure Of the Eye
Normally, aqueous humor (the fluid in the front chambers of the eye) is able to drain away at the same rate it is produced, keeping everything balanced. Glaucoma occurs when the drainage canals become blocked. Pressure begins to build, which eventually pushes the lens back. This, in turn, causes the vitreous humor (the fluid in the larger rear chamber of the eye) to press against the blood vessels and optic nerve, damaging them.
The Different Types Of Glaucoma
The two most common types of glaucoma are open-angle glaucoma and angle-closure glaucoma. At least 90 percent of all glaucoma cases are open-angle. Rarer types of glaucoma include congenital (from birth) and traumatic (caused by injury), and there are several others.
Open-angle glaucoma develops very gradually, as the drainage canals of the eye become clogged and the fluid isn’t able to drain effectively. What makes open-angle glaucoma so nefarious is that it rarely has noticeable symptoms. The peripheral vision gradually goes dark, but the central vision remains sharp, so it may seem like nothing is wrong until the condition has advanced. This is why regular comprehensive eye exams are essential, particularly after age 60 (or earlier if there is family history of glaucoma).
Angle-closure glaucoma occurs when the iris itself blocks those drainage canals, causing a much more sudden rise in pressure and obvious symptoms, such as headaches, eye pain, nausea, rainbows around lights at night, and very blurred vision. If you experience these symptoms, come see us immediately. We can also check if your angle is wide or narrow to determine whether you’re at risk of developing angle-closure glaucoma.
Stopping Glaucoma In Its Tracks
The lack of early symptoms in the vast majority of glaucoma cases might seem scary. The good news is that as long as you come in for your regular eye exams, we can detect glaucoma much earlier than you can, and then we can treat it. Before age 60, it’s usually enough to have one eye exam every two years, but people over 60 should schedule them once a year. Your individual risk factors may require more frequent exams.