Peripheral vision loss can be sudden, or come on gradually and subtly, and can make everyday life difficult. Having peripheral vision loss might cause someone to trip, for example, or struggle with walking in the dark or have trouble driving. This type of vision loss is typically the result of a medical condition.
Peripheral vision is what you see to your left and right as you look straight ahead. In other words, peripheral vision is what you see “out of the corner of your eye.” Peripheral vision is different from central vision, which is what you see in the center of your visual field as you stare straight ahead.
Problems with peripheral vision mean you do not have a wide field of vision, even though your central vision is fine. It can cause “tunnel vision,” which is the sensation of looking through a narrow tube.
Peripheral vision loss can cause other effects, such as seeing a “spider web” or “curtain” off to the side of the visual field. Sometimes people may see shimmers of light followed by tunnel vision in episodes that last ten to twenty minutes. In some cases, the individual may not experience any symptoms at all.
Some people begin to notice peripheral vision loss once they can no longer see 40 degrees or more from your side vision. Government agencies often classify someone who cannot see beyond 20 degrees of their visual field as legally blind.
About the Eye and Peripheral Vision
Light carries visual information about the world around you. Light enters the eye through the pupil and strikes a light sensitive layer of tissue, known as the retina, lining the back of the eye. Special photoreceptor cells, known as rods and cones, absorb the light. Rods are responsible for absorbing light in low-light environments, while cones are responsible for colour and sharp vision.
After rods and cones absorb light, the retina converts the visual information into electrical impulses. The retina then sends these signals through the optic nerve to the brain, which translates the impulses into the images you perceive.
Most of the rods and cones are at the center of the retina, in an area known as the macula. Having a high concentration of rods and cones in the macula provides sharp central vision that you use for reading, driving, and seeing faces.
Loss of peripheral vision happens as the result of damage to the retina, macula or optic nerve, or as the result of a brain injury, like that caused by a stroke.
Causes of Peripheral Vision Loss
A number of conditions can cause peripheral vision loss, also known as a peripheral field defect. Eye problems account for most causes, but catastrophic brain events can also lead to problems with peripheral vision.
When it comes to glaucoma, peripheral vision loss is common. Optic nerve damage from glaucoma prevents the electrical impulses made by the retina from reaching the brain. Unlike many conditions that affect both eyes, glaucoma can cause the loss of peripheral vision in one eye.
Glaucoma is a group of eye conditions that cause abnormally high pressure within the eye, which damages the optic nerve. Pressure and optic nerve damage directly affects peripheral vision. Left untreated, the high intraocular pressure can cause permanent damage to the optic nerve and lead to irreversible blindness.
Retinitis pigmentosa is an inherited condition characterized by the breakdown and loss of cells in the retina. While this condition usually affects both eyes, it can cause loss of peripheral vision in one eye.
Diabetic retinopathy is a serious complication of diabetes, a condition characterized by high blood sugar that causes blood vessels to leak blood and fluids into the retina. The more advanced stage of diabetic eye disease, known as proliferative diabetic retinopathy (PDR), can cause both central and peripheral vision loss.
Damage to the retina may cause a blind spot in vision, known as a scotoma. The blind spot may be the result of glaucoma, inflammation, macular degeneration, or another eye condition.
A stroke damages one side of the brain. In some cases, a stroke can damage areas of the brain responsible for processing visual images, leading to blind spots in peripheral vision and in other areas of the visual field. While your eyes are still in working order after a stroke, your brain cannot process what your eyes see. Peripheral vision loss after stroke is common, and a stroke can cause permanent vision loss on one side of each eye.
In fact, the most common type of peripheral vision loss after stroke is homonymous hemianopia, a condition in which the person can only see the right half or the left half when looking out of each eye.
This is because the right side of the brain is responsible for the left side of vision in both eyes, while the brain’s left side is responsible for the right side of vision in both eyes.
The pathway between the eyes and the part of the brain that interprets visual impulses from the retina is lengthy; because it is so long, the pathway is vulnerable to damage during a stroke. Stokes in some locations along the pathway affects the entire right side or the entire left side of one or both eyes. At other times, these strokes affect only peripheral vision.
A migraine is a type of headache that can cause vision changes, which may include temporary peripheral vision loss.
Occlusions, also known as “eye strokes,” occur when a blood clot or narrowed blood vessels block the flow of blood to the retina. Occlusions are especially dangerous to vision when they block blood flow to the optic nerve.
Permanent vs Temporary Loss of Peripheral Vision
Peripheral vision loss may be temporary or permanent, depending on the condition that caused it. Conditions that can cause permanent peripheral vision loss include:
- Retinitis pigmentosa
- Diabetic retinopathy
Conditions that can cause temporary loss of peripheral vision include:
Symptoms of Peripheral Vision Loss
Symptoms of peripheral vision loss may develop slowly or suddenly, depending on its cause. Symptoms of peripheral vision loss include:
- Bumping into objects
- Difficulty navigating crowded spaces, such as in shopping centers or at events
- Being unable to see well in the dark, a condition known as “night blindness”
- Difficulty driving, particularly at night
These symptoms can develop in just one eye or in both eyes. They can be the result of sudden loss of peripheral vision or gradual loss.
Anyone experiencing a gradual onset of these symptoms should make an appointment with an eye doctor. Anyone experiencing sudden loss of peripheral vision should seek emergency medical care, as this may be a sign of a detached retina that needs prompt treatment to avoid permanent vision loss.
Treatments for Peripheral Vision Loss
Treatment depends largely on the cause. To determine the underlying cause, eye doctors will perform a battery of tests, including visual field tests to determine losses in peripheral vision. They then can recommend possible treatments.
In many cases, prevention is the next best thing to treatment. Taking glaucoma medications as directed can keep high eye pressure under control, for example, to prevent optic nerve damage and the development of permanent loss of peripheral vision. Therapy for blind spots can help alleviate peripheral vision loss caused by brain damage.
Available Assistive Technology
Electronic eyewear can help with many of the conditions that cause peripheral vision loss. While they cannot restore peripheral vision, they help many improve their overall vision.
eSight glasses is a low vision eyewear device that stimulates synaptic activity from the remaining photoreceptor function of its users’ eyes. Many successful eSight users live with peripheral vision loss caused by glaucoma, retinitis pigmentosa, diabetic retinopathy and more.
Fortunately, eSight can stimulate synaptic activity from the remaining photoreceptor function of the user’s eyes. As a result, eSight makes clearer vision possible, resulting in enhanced vision of up to seven lines on a doctor’s eye chart. It uses a cutting edge camera, smart algorithms and high resolution screens, and provides the flexibility to read books up close with the same ease as seeing a crosswalk sign from a distance.
Users have been able to see their family’s faces for the first time in decades, resume their hobbies and jobs, and regain confidence in their daily lives. Legally blind eSight user Larry Kupner who lives with retinitis pigmentosa, describes that his life has become more productive and independent with his enhanced vision, and he is able to clearly see his family, friends, and the great outdoors again. With eSight, Larry is able to read at an astounding 20/40 visual acuity.