Blindness refers to partial or complete loss of vision. It has many potential causes, such as eye injuries, genetic diseases, and age-related changes.
Many people associate blindness with a complete inability to see, but this only occurs in a small number of people with vision loss. Most people with blindness still maintain at least some degree of light detection.
Blindness has many potential causes that may occur from birth or develop throughout your life. The
Read on to learn more about types of blindness, potential causes, and treatment options.
Healthcare professionals divide blindness into various levels of severity.
Total blindness
Total blindness means you can’t perceive any light. Total blindness only occurs in about
Low vision
- glasses
- contacts
- medications
- surgery
People with low vision might have trouble:
- reading
- driving
- recognizing faces
- differentiating colors
- seeing a TV or computer screen
Low vision might occur in your central vision or peripheral vision.
Legal blindness
“Legal blindness” is a term used by the United States government to determine aid eligibility. To qualify, you need a visual acuity of less than 20/200. This means you need to stand 20 feet away from something to see it with the same sharpness as a person with normal vision standing 200 feet away.
Visual impairment
“Visual impairment” is a general term that describes vision loss that interferes with daily activities. The
| Visual impairment level | Near normal |
|---|---|
| Normal | 20/10 to 20/25 |
| Near normal | 20/30 to 20/60 |
| Moderate | 20/70 to 20/160 |
| Severe | 20/200 to 20/400 |
| Profound | 20/500 to 20/1,000 or 6 to 10 degrees of visual field |
| Near total | • less than 5 degrees • passing at least one of the following tests: counting fingers, hand motion, or light perception |
| Total | no light perception |
Age-related blindness refers to eye disorders that become more common with age. Types of age-related conditions that can cause vision loss include:
- Cataracts: Cataracts are cloudy areas in your lens that may make your vision blurry, reduce night vision, or wash out colors. They affect more than
90% of people over 80 years old. - Age-related macular degeneration (AMD): AMD is the breakdown of the central part of your retina in the back of your eye due to age-related changes. It may cause blurry vision or loss of central vision. Close to
20 million adults in the United States over 40 years are thought to have AMD. - Glaucoma: Glaucoma is a group of eye conditions that involve optic nerve damage. Blurry vision or seeing halos around lights can be early warning signs. glaucoma is thought to affect about
3 million people in the United States. What makes it dangerous is that it often doesn’t cause symptoms until it is advanced. - Diabetic retinopathy: Diabetic retinopathy occurs due to damage to the retina from chronically high blood sugar levels. It might cause gradual worsening or sudden loss of vision. It’s estimated to affect close to
10 million people in the United States.
Traumatic eye injuries can lead to minor or total loss of vision. They can occur due to:
- falls or car collisions
- accidents involving explosives, fireworks, or projectiles
- toxins
- chemical burns
- physical violence
- sport injuries
Many infectious diseases can lead to vision loss.
Trachoma is the
Some noninfectious conditions that can lead to reduced vision include:
- Stroke: As many as
65% of people who have a stroke have vision problems, such as blurry vision. Close to800,000 people in the United States have a stroke each year. - Cancer: Eye cancer is rare, but there are about
3,320 new cancers of the eye each year in the United States. It can cause many different symptoms like eye pain or loss of vision. - Amblyopia: Amblyopia is also called a lazy eye. It affects up to
2% of people globally and can cause vision loss if not treated promptly. It occurs in children. - Retinopathy of prematurity: Retinopathy of prematurity is a condition that causes swelling in the blood vessels at the back of the eye of some premature babies. About
20,000 babies born prematurely each year globally become severely visually impaired.
Nutritional blindness is most common in developing countries with limited access to nutritious food. It refers to a deficiency in vitamin A. Up to
Vitamin A deficiency can lead to extreme eye dryness and permanent vision loss.
Night blindness is when you have trouble seeing in low light. It can occur due to conditions like:
- nearsightedness
- cataracts
- retinitis pigmentosa
Many different genetic and congenital conditions can cause blindness. They include:
- leber congenital amaurosis
- retinitis pigmentosa (RP)
- achromatopsia
- Stargardt disease
- Best disease
- X-linked retinoschisis
- choroideremia
- congenital stationary blindness
Color blindness is an inability to see certain colors. Contrary to popular belief, most people with color blindness still see colors, but they often can’t differentiate between certain colors. The
Having a complete inability to see color is known as monochromacy and is very rare.
Snow blindness occurs when your eyes are exposed to too much UV light. The name comes from it commonly occurring due to the reflection of sunlight off of snow. It’s similar to receiving a sunburn on the surface of your eye. It may occur due to exposure to:
- the sun
- welding arcs
- tanning lamps
- therapeutic UV equipment
It usually resolves within a day or 2 without any treatment.
Some of the treatment options for blindness include:
| Cause | Treatment |
|---|---|
| Glaucoma | • medications • surgery • laser treatment |
| Age-related macular degeneration | • anti-VEGF injections for wet macular degeneration |
| Cataracts | • surgery |
| Diabetic retinopathy | • anti-VEGF injections • laser treatment • eye surgery • blood sugar management |
| Traumatic injury | • emergency treatment • surgery for serious injuries |
| Infectious disease | • antibiotic or antiviral medications • medications to reduce inflammation |
| Nutritional blindness | • nutritional support |
| Stroke | • medications to reduce the risk of blood clots • surgery |
| Color blindness | • special glasses or contacts to help improve color detection |
Blindness has many causes including genetic conditions, age-related changes, or traumatic injuries. Most people with blindness maintain some degree of vision.
Some types of blindness, such as blindness caused by some genetic diseases, aren’t preventable. You can minimize your chances of developing blindness caused by traumatic eye injuries by following proper eye care safety during activities with a high risk of eye injury, like discharging firearms or playing contact sports.