What causes tunnel vision?
Tunnel vision is the term for loss of peripheral eyesight. This leaves you with a clear field close to the center of your vision but with blurred or totally absent vision around the edges. This can cause real issues for you if you're trying to drive, work, or just get by in the world.
Understanding tunnel vision
Definition and characteristics
Tunnel vision is defined by a loss of vision around the edges of your visual field. The area around your central field of view can be blurry or dark, which creates a tunnel effect where you can only see clearly straight ahead. People with tunnel vision may be able to see clearly, but the only way to build up a picture of the world around them is to continuously scan around with your eyes to compensate for the loss of side vision.
Impact on daily life
This causes some serious problems for people with tunnel vision. If you can't see side to side, you might not be able to see hazards to the left and right, which is a problem for more than just catching stray foul balls. If you don't have good peripheral vision, it might not be safe for you to drive or operate heavy machinery. You can also get eye strain and migraines from having to continuously scan your surroundings just to get a clear picture of the world around you.
Medical causes of tunnel vision
Tunnel vision can have lots of causes, some affecting the light-sensitive cells of the eye and others affecting the optic nerve itself. You could also get tunnel vision from certain brain injuries or neurological disorders.
Glaucoma
Glaucoma is a condition where pressure builds up inside your eye until the optic nerve suffers damage. This gradually shuts down your vision, usually from the edges inward. During most of the disease's progress, you'll experience this as a darkening of your field of vision. Glaucoma is partly hereditary, but you're more likely to get it if you have diabetes, high blood pressure, or sickle-cell anemia.
Retinitis pigmentosa
Retinitis pigmentosa is what science nerds call it when you have a congenital disease of the retina. This is where the light-sensitive cells are situated in your eye, and RP (as the kids call it) gradually degenerates this region until the cells have mostly died and you've lost most or all your vision.
Optic nerve disorders
The optic nerve is the pipe that carries visual information to the back of your brain, where it plugs into your visual cortex. Any damage or disruption along its length can affect how we see, and even a minor loss is likely to produce tunnel vision.
This is because we have way, way, way more light-sensitive cells in the center of our visual field than on the edges. Thus, if you lose even 10% of the input from your optic nerve, you'll probably still have more or less okay vision in the center, where the vast majority of photoreceptors are, but you may entirely lose input from the smaller number of cells on the edges.
Migraines and aura
You can get temporary tunnel vision from migraines. Auras are a really common side effect of migraines, which is usually felt as wavy or dimmed vision throughout your field of view. Just as with optic nerve loss, you have more cells in the middle of your eye than at the edges, so a disturbance that affects your vision generally is more likely to be perceived as a loss of side vision, producing that tunnel effect for as long as you have the migraine.
Brain tumors and lesions
"Brain tumor" is paradoxically the first thing you're likely to diagnose yourself with on WebMD and the last thing you're actually likely to have. Some people do get them, however, and they can cause tunnel vision sometimes. A tumor in the occipital lobe of the brain (the bulgy bit in the back where vision is processed) might interfere with blood flow or directly press on the visual cortex. This is not one of those things you can diagnose yourself, so you really should ask your health care provider about this if you suspect it after getting an eye exam.
Stress and anxiety
Some people react to stress in odd ways. You might experience what used to be called hysterical blindness, which, all joking aside, is as real as wearing a blindfold and can have the same impact on your life. This might be a purely psychological phenomenon in some cases, or it might be because your stress caused a spike in blood pressure and pressed your optic nerve the wrong way.
Identifying and managing tunnel vision
Tunnel vision is the loss of peripheral visual acuity, and it has a lot of causes, from brain tumors to "meh, just one of those things." Always get it checked out, though, because it could be serious. We can help you find an eye care professional near you if you'd like to set up an appointment today.
FAQ
Can tunnel vision be permanent, or is it always reversible?
Tunnel vision can be a permanent thing, or it might go away with time and treatment. Discuss treatment options with your doctor.
Are there lifestyle changes or therapies to manage tunnel vision caused by stress?
Lifestyle changes for tunnel vision focus on reducing the likelihood you'll get it. Eat right and rest a lot, keep your blood pressure down, and get regular eye exams to reduce your risk.
Can tunnel vision be a symptom of a medical emergency?
Tunnel vision can be a symptom of uncontrolled diabetes, a brain tumor, or rapidly progressing glaucoma. It's always a good idea to get it checked because it could be serious.