An eye condition that cannot be corrected with glasses or surgery is called low vision. Usually, this condition interferes with daily activities. A vision specialist can test your vision and make a personalized treatment plan.
In other words, low vision is a permanent condition that does not improve with contact lenses, glasses, or surgery. Mostly, doctors define this eye disorder as moderate to severe visual impairment that negatively affects your ability to perform daily tasks (including driving and reading). The medical terms like “partially sighted” and “legally blind” belong to a large group of disorders known as low vision. However, these terms can have more specific meanings. For instance, in the U.S., doctors use these terms to describe a person who qualifies for special education or disability services for visual impairment.
This condition also involves different types of visual impairment, not only farsightedness or nearsightedness. However, it also includes peripheral vision loss, a blind spot or blurred vision, and other vision problems. You should also know that low vision is not complete blindness, and there are some vision rehabilitation services that help people perform their daily activities.
What Qualifies as Low Vision on a Visual Acuity Test?
Generally, the standard visual acuity test in the U.S. is the Snellen eye chart. It is used to measure the vision clarity at a distance of 20 feet from an object. People who have 20/20 vision (the average score) can see objects clearly at this distance. When the score is 20/70, it means that your vision at 20 feet is similar to normal vision at 70 feet. According to the World Health Organization (WHO), moderate to severe visual impairment has a score of 20/200 or above.
However, this is not the only test visual specialists consider. For example, they also perform a visual field test to measure the range of vision from side to side. Usually, your vision is qualified as low vision if you have a visual field of 20 degrees or less. Additionally, some people who have low scores on the previous tests can correct their vision with glasses, contact lenses, or surgery. When these treatments help correct your vision, it means you do not have low vision.
What Are The Symptoms of Low Vision?
Commonly, low vision manifests in different ways among people. For instance, you may have a loss of:
- Depth perception (the ability to judge the distance between objects)
- Peripheral vision (the ability to see out of the sides of your eyes)
- Central vision (the ability to see what is in front of you)
- Contrast sensitivity (the ability to distinguish objects)
- Night vision (the ability to see in low light or at night)
- Glare resistance (the ability to function in bright light)
Usually, people with low vision difficulty perform the following activities. These include driving, cooking, reading, classroom learning, watching TV or videos, using a computer, and recognizing the faces of other people. Check below also some symptoms that you can notice in your child if it has low vision:
- Eyes that flutter or dance or that do not point the same way
- Gray or white pupils
- Different sizes of pupils
- Frequently squinting, blinking, or shutting or covering one eye
- Holding objects very close to their face
- Frequently bumping into things
Those who develop low vision may also experience decreased physical and social activity, hallucinations (also known as Charles Bonnet syndrome), anxiety, depression, and a loss of independence. Do not hesitate to visit a doctor if you or your child has any of the previous symptoms.
Causes
Typically, there is a long list of things and health conditions that may lead to low vision. Check the most common of them below:
- Macular degeneration – This disorder causes a gradual loss of central vision. Those who are affected by this condition may also experience a blurry or blind spot in the central visual field. Mostly, it affects people over 50 years old.
- Cataracts – This condition also occurs more frequently in older adults, and it causes a cloud on the eye lens. While cataract surgery can remove it, this surgery is not an option for everyone.
- Glaucoma – It is a progressive eye disorder that can cause damage to the optic nerve without immediate treatment. Most of the time, glaucoma affects the peripheral and night vision.
- Diabetes-related retinopathy – People who develop this condition may notice that blood vessels in one eye leak fluid. As a result, it causes pressure against the retina, which damages it over time.
- Retinopathy of prematurity – Sometimes, babies born pre-term and treated with incubation may develop abnormal blood vessels in their retinas. In rare cases, this condition can cause chronic complications.
- Lazy eye (also known as amblyopia) – This is a congenital (present at birth) condition that makes the vision blurred in one eye. In people with this condition, the brain mostly relies on the good eye and ignores the bad one, which may lead to eye drifting.
However, there are other conditions that may also contribute to low vision. Examples include:
- Refractive errors – These errors negatively affect the shape of your eye, which may lead to farsightedness and nearsightedness. Leaving these errors untreated may cause serious complications over time.
- Trachoma – This is a bacterial infection that may cause irritation and damage to the eyes. Furthermore, it is one of the most common causes of blindness worldwide (especially in less developed countries).
- Strabismus (misaligned eyes) – This eye condition is caused by a problem with the muscles that control eye movements. Usually, it appears in infancy or early childhood.
- Nystagmus – This health condition causes sudden, uncontrollable eye movements, which affect the ability to focus your vision. While it can be present at birth, some people develop it later in life.
- Retinitis pigmentosa – This medical term is used to describe multiple inherited eye disorders that prevent the retina from working properly. It happens due to different genetic mutations.
- Hypersensitive retinopathy – This is a serious eye disease in which chronic (long-term) hypertension (high blood pressure) disrupts blood flow to the organs (including the retina). As a result, people with hypersensitive retinopathy may experience vision loss.
- Retinal detachment – This condition is often painless but serious because it causes the retina to detach from the tissues that support it. As a result, the blood flow to the retina is interrupted, which may cause a sudden and permanent loss of vision.
- Optic atrophy – In people with this condition, the optic nerve gradually deteriorates. It may happen due to multiple reasons, including injuries, infections, and blood flow problems.
- Eye injuries – Any injury to the eye can cause long-lasting damage (especially if it is not diagnosed and treated immediately).
- Brain injuries – Anything that causes brain damage may lead to vision problems. Commonly, the first symptoms are headaches and dizziness.
- Vitamin A deficiency – This vitamin is essential to your vision. When the body does not absorb enough vitamin A, or you do not get enough from your diet, it may lead to vision problems (including night blindness).
- Eye cancer – You should know that all types of eye cancer occur quite rarely, but they can cause blindness. Furthermore, cancer treatments may also affect your vision by causing damage to certain eye parts.
Is There a Way to Prevent Low Vision?
One of the best ways to prevent permanent vision loss is to have regular checkups with your healthcare professional. Generally, most causes of low vision are preventable, especially if they are found and treated in the early stages.
Diagnosis
Most of the time, this condition is diagnosed by ophthalmologists. They often begin the diagnosis with a physical examination and questions about your symptoms and medical history. However, to confirm or rule out this disorder, doctors may perform some vision tests. These include visual acuity tests, visual field testing, contrast sensitivity tests, and low vision examination.
Treatment
Mostly, doctors recommend different treatments for people with low vision because they depend on several factors. These include the type, cause, and severity of low vision, overall health, age, sex, and preferences. Check some common options used to manage low vision below:
Vision Rehabilitation
The goal of this treatment is to maximize your vision as much as possible and prevent serious complications (such as a complete loss of vision). Doctors often recommend:
- Glasses or contact lenses
- Electronic magnifiers and screen readers
- Optical magnifiers or telescopes
- Large print or high contrast products
- Audible home devices
- Voice-to-text and audio reading technology
Your ophthalmologist may also recommend the following options to relieve the symptoms and improve your vision. Examples include:
- Occupational therapy
- Special education or vocational services
- Participating in support groups in which other people with low vision share their experiences
- Counseling or psychotherapy
Frequently Asked Questions
How do you treat low vision?
Most of the time, this condition is permanent, which means it cannot be treated with glasses, contact lenses, or surgery. However, doctors may recommend some options to reduce the progression of the disease and help you perform daily activities more easily.
What are the most common causes of low vision?
The leading causes of this condition in the U.S. are age-related eye diseases, including diabetic retinopathy, macular degeneration, cataracts, and glaucoma. In any case, this condition can be caused by other eye conditions that are left untreated.
What foods may help improve eyesight?
Once you are diagnosed with low vision, doctors may recommend a diet rich in vitamins, antioxidants, and omega-3 fatty acids, along with the main treatment. This diet helps protect your eyes from further damage, supports retinal health, and reduces the risk of developing certain eye diseases (including macular degeneration and cataracts).
Can low vision get worse over time?
Yes. Whether low vision worsens depends on its underlying cause. Progressive eye diseases such as glaucoma, age-related macular degeneration, and retinitis pigmentosa may lead to further vision loss over time, especially if they are not properly managed. Regular eye examinations and following your treatment plan can help slow disease progression in many cases.
What is the difference between low vision and blindness?
Low vision refers to permanent visual impairment that cannot be fully corrected with glasses, contact lenses, medication, or surgery but still allows some usable vision. Blindness usually refers to severe vision loss with little or no functional sight. Many people with low vision retain enough vision to perform daily tasks with the help of rehabilitation services and assistive devices.
Can children develop low vision?
Yes. Low vision can occur at any age, including infancy and childhood. It may result from congenital eye disorders, genetic conditions, premature birth, eye injuries, or diseases affecting the eyes or brain. Early diagnosis and intervention can improve a child’s learning, development, and quality of life.
What assistive devices are available for people with low vision?
Many assistive devices can help people remain independent. These include handheld and electronic magnifiers, closed-circuit television (CCTV) magnification systems, screen-reading software, text-to-speech devices, large-print books, talking watches and clocks, smartphone accessibility features, and enhanced lighting systems. An eye care specialist can recommend the most appropriate devices based on your needs.
Can people with low vision still drive?
It depends on the severity of vision loss and the vision requirements in your state or country. Some people with mild visual impairment may still qualify to drive if they meet legal vision standards, while others may need to stop driving for safety reasons. Your ophthalmologist or optometrist can determine whether your vision meets the legal requirements for driving.
Does low vision increase the risk of falls and injuries?
Yes. Reduced vision can make it more difficult to recognize obstacles, judge distances, and navigate unfamiliar environments. As a result, people with low vision have a higher risk of falls, fractures, and other accidents. Improving home lighting, removing tripping hazards, using mobility aids when necessary, and participating in vision rehabilitation programs can help reduce these risks.
When should I see a doctor about changes in my vision?
You should seek medical attention promptly if you notice sudden vision loss, flashes of light, a sudden increase in floaters, severe eye pain, double vision, or a curtain-like shadow over your field of vision. These symptoms may indicate serious eye conditions, such as retinal detachment or acute glaucoma, which require immediate treatment to help preserve vision. Ask your healthcare provider if you have any other questions.
