08/08/2026
What is blindness?
Blindness is the inability to see or a lack of vision. In the most severe cases, there’s an inability to see even light. It also means that you can’t correct your vision with eyeglasses, contact lenses, eye drops or other medical therapy, or surgery. Sudden vision loss is an emergency. It’s important to seek immediate medical help.
Types of blindness
🫴🏿Partial blindness: You still have some vision. People often call this "low vision."
🫴🏿Complete blindness: You can't see or detect light. This condition is very rare.
🫴🏿Congenital blindness: This refers to poor vision that you are born with. The causes include inherited eye and retinal conditions and non-inherited birth defects.
🫴🏿Legal blindness: This is when the central vision is 20/200 in your best-seeing eye even when corrected with glass or contact lenses. Having 20/200 vision means that you have to be 10x closer or an object has to be 10x larger in order to see compared to a person with 20/20 vision. In addition, you can be legally blind if your field of vision or peripheral vision is severely reduced (less than 20 degrees).
🫴🏿Nutritional blindness: This term describes vision loss from vitamin A deficiency. If the vitamin A deficiency continues, damage to the front surface of the eye (xerophthalmia) This type of blindness can also make it more difficult to see at night or in dim light due to retinal cells not functioning as well.
You might wonder about color blindness, which is not blindness in the traditional sense. Another name for this issue is color deficiency. You perceive colors in a different way. You can inherit this condition or acquire it because of disease or damage that occurs in your retina or optic nerve. If you can only see black, white or shades of gray, you have achromatopsia.You may also hear about preventable blindness or avoidable blindness. These terms refer to blindness that happens to people that have a diseases that is treatable but they never receive care. This often happens because of a lack of access to eye care or healthcare. For instance, people who never receive care for diabetes may develop diabetes-related retinopathy. People who don’t receive care for hypertension may develop hypertensive retinopathy.
How common is blindness?
Blindness is common throughout the world and in the U.S. It can happen to anyone.
In the U.S., about 1 million people are blind. Experts expect this number to double by 2050. There are many more people with low vision. Around the world, an estimated 43 million people are living with blindness.
Symptoms and Causes
What are the symptoms of blindness?
With complete blindness there is a lack of vision and the inability of the eye to detect light.
Symptoms that you may have while vision loss develops include:
Blurry vision.
Eye pain.
Floaters and flashers.
Sensitivity to light (photophobia).
Sudden loss of vision, or the sudden appearance of black spots in your vision.
What causes blindness?
There are many causes of blindness, including injuries, infections and medical conditions.
Eye injuries and blindness
Eye injuries, or ocular trauma, can happen in many ways. It usually affects only one eye. Damage can result from:Chemical burns.
Exposure to toxins
Fights.
Fireworks.
Industrial accidents, including falls.
Motor vehicle crashes.
Sports.
Infections and blindness
Many infectious diseases can lead to vision loss and sometimes blindness. These include:
Trachoma. This is the leading cause of preventable blindness in the world.
Cytomegalovirus.
Endophthalmitis.
Histoplasmosis.
Keratitis, including acanthamoeba keratitis.
Rubella.
Shingles.
Syphilis.
Toxoplasmosis.
Uveitis.
Non-infectious diseases and blindness
Many non-infectious diseases can cause blindness, but some in only the most severe stages of the disease. These include:
🫴🏿Retinitis pigmentosa. This term refers to a group of conditions that affect your retina, the part of your eye that has special cells that react to light. As the condition progresses, the retinal cells break down. This leads first to problems seeing at night and then subsequent loss of your peripheral vision.
🫴🏿Age-related macular degeneration. This condition affects the macula, the part of your retina that controls central vision. When substantial central vision loss occurs, tasks like reading or recognizing people’s faces become very difficult, but your peripheral vision often remains intact.
🫴🏿Retinopathy of prematurity. This retinal condition happens to some premature babies. Blood vessels grow into parts of their eye where they don’t belong. Scar tissue forms and can damage their retina, leading to significant vision loss and blindness.
🫴🏿Cataracts. Cataracts cause vision loss by clouding the lenses of your eyes, leading a blurring of the vision and loss of contrast. Without access to surgical care, advanced cataracts can lead to blindness.
🫴🏿Diabetes-related retinopathy. This condition may happen when you have diabetes and the blood vessels in the eye are damaged. The vision loss may be mild at first, but with progression or lack of treatment, blindness can occur.
🫴🏿Glaucoma. With this condition, you have optic nerve damage. The vision loss often starts in the periphery but can lead to blindness in advanced stages of the disease.
🫴🏿Leber hereditary optic neuropathy. This term refers to an inherited type of gradual vision loss. For unknown reasons, it affects males more than females.
🫴🏿Anophthalmia. This disease happens when you’re born without one or both eyes.
🫴🏿Microphthalmos. This disease happens when you’re born with very small eyes. Sometimes these smaller eyes don’t work as well as they should, or at all.
🫴🏿Stroke. You can lose your eyesight from a stroke that occurs in an area of the brain that is involved in seeing, like the occipital lobe or along the visual tract. The stroke reduces or blocks blood flow to your brain.
🫴🏿Cancer. Cancers, like retinoblastoma or orbital tumors, can cause eyes to become blind.
🫴🏿Nutritional deficiencies. A poor diet can cause vision loss. Vitamin A deficiency is one cause, but you also need B vitamins and other minerals and vitamins for healthy vision.
