While staring straight ahead and without moving your eyes or head, try to be aware of the objects to the left and right, above and below you. These objects lie outside your central field of vision, in what is called your peripheral vision.
Peripheral vision is the part of our vision that is outside the center of our gaze, and it is the largest portion of our visual field. A normal visual field is approximately 170 degrees around, with 100 degrees comprising the peripheral vision.
Peripheral vision is broken down into three segments of the field of view:
Far-peripheral vision: the vision at the edge of the field of view
Mid-peripheral vision: the vision in the middle of the field of view
Near-peripheral vision: the vision just adjacent to the center of gaze
Most people do not appreciate their peripheral vision until they begin to lose it. The loss of peripheral vision results in a condition known as tunnel vision. The opposite condition—the loss of your central vision while retaining your peripheral vision—is known as central scotoma.
Peripheral vision is weaker in humans than in many other species, and this disparity is even greater where it concerns our ability to distinguish color and shape. This is due to the density of the receptor cells on the retina.
The retina is a layer of tissue located in the back of the inner eye that converts light images to nerve signals and transmits them to the brain. The receptor cells on the retina are densest at the center—the area known as the macula—and more diffuse at the edges. There are two types of receptor cells: rod cells and cone cells.
Rod cells are essential for seeing in dim light, but they are unable to distinguish color. Cone cells are concentrated in the center of the retina and enable us to see bright lights and color.
So what happens when we lose our peripheral vision? Let’s go over that now.
Peripheral Vision Loss
Symptoms of peripheral vision loss—which may be very subtle, and may not even be detected by the patient—may include difficulty seeing in dim light and a decrease in ability to navigate while walking.
Many eye care professionals agree that the loss of peripheral vision (also known as peripheral field deficit) is linked to nerve damage, which can be caused by glaucoma or injury, among other things. Additional causes of peripheral vision loss may include:
- Eye strokes or occlusions
- Detached retina
- Brain damage from stroke, disease, or injury
- Optic neuritis and other conditions that cause neurological damage
- Compressed optic nerve head (papilledema)
If you feel you are losing your peripheral vision, you should see an eye doctor immediately. He or she will give you a visual field test to determine where your blind spots are located. Any sudden decrease or loss of peripheral vision is a reason to seek medical attention immediately, since it could indicate a serious problem—for example, a detached retina.
Treatment for peripheral vision loss may not be as simple as wearing eyeglasses. Occasionally a prism can be added to eyeglasses to help expand the field of view. In most cases, however, your eye doctor will want to determine the cause of the loss and treat that first, in hopes of restoring your peripheral vision or at least preventing further loss.
What to Expect When Testing Your Peripheral Vision
There are several ways to test your peripheral vision. Some tests can be done at home rather than at your doctor’s office, but only an eye doctor can give you a correct diagnosis. Three major tests are used to determine the extent of your peripheral vision loss:
- Automated Perimetry: During this exam, you sit in front of a dome or cone and stare at an object in the middle. You press a button when you see small flashes of light in your peripheral vision.
- Confrontation Visual Field Exam: During this exam, your eye doctor sits directly in front of you. While you cover one eye at a time and stare straight ahead, your doctor asks you to tell him or her when you can see their hand moving in front of you.
- Tangent Screen: This test is also known as the Goldmann Field exam. When taking this test, you sit approximately three feet away from a screen with a target in the center. You are then asked to stare at the target and tell your doctor when you can see an object moving into your peripheral view. This exam creates a map of your peripheral vision.
Most people do not need to prepare for any of these exams, which generally cause no and do not require any eyedrops. By conducting peripheral vision tests, your eye doctor should be able to detect any loss or decrease in your peripheral vision.
If your results are poor, additional tests may be performed by your eye doctor or another medical professional. For example, a Humphrey Visual Field test may be administered in order to rule out glaucoma.
Peripheral Vision Loss Treatment Options
Unfortunately, treating peripheral vision loss is not always easy. Some will benefit from adding a prism lens to their eyeglasses, but for most, treatment may depend on the underlying cause. For example, if you have glaucoma you may need to use prescription eye drops or laser treatment to prevent further loss of your visual field.
Therapy may also be beneficial to those whose peripheral vision loss has been caused by some form of brain damage. In some cases a sports therapist can help you improve your peripheral vision with special exercises.
Questions for Your Doctor
- How much of my peripheral vision has been lost?
- What is causing the decrease in my peripheral vision?
- How often should I come in to see you for eye check-ups?
- Next time I come in, which tests will be conducted?
- Will I need to find a ride to my next appointment?
- Which treatment options will benefit me most?
- What can I change in my diet to improve my peripheral vision?
- Can you refer me to a sports therapist to help improve my visual field?