While vision loss may be a normal part of getting older, complete blindness is not. Blindness—a near or total lack of vision—affects around 43.3 million people around the world. Around half a million children go blind each year, whether they are born blind or become blind due to an accident or illness.
Blindness is a common disability, but many people don’t know much about it. What is life like for someone who is blind? And how do you approach the world when your sight needs change?
In this article, Ability Central answers seven important questions about blindness, including:
What is blindness?
What are the different types of blindness?
How common is blindness in adults?
What conditions cause blindness?
Is blindness preventable?
Can a person lose both their hearing and their vision?
Where can I get more information about blindness?
What is blindness?
In the simplest terms, blindness is the inability to see. However, the condition can be much more complex.
Someone who is blind cannot correct their vision with glasses, surgery, or medication. Someone who is completely blind cannot see shapes, colors, or light.
What are the different types of blindness?
There are five main types of blindness:
Partial blindness
Legal blindness
Complete blindness
Nutritional blindness
Congenital blindness
Partial blindness
People with partial blindness, also called low vision, still have some vision.
For someone with low vision, their sight might be:
Blurry
Cloudy
Dim
Color impaired
Blocked by dark spots or “floaters”
Legal blindness
Legal blindness refers to vision measured below 20/200 in their best-seeing eye. Compared to someone with standard vision, measured at 20/20, someone with 20/200 vision would need to stand ten times closer to an object to see it clearly.
Someone may also be considered legally blind if their peripheral vision—what they see at the edges of their vision—is gone or severely limited.
Complete blindness
Someone who is completely blind can’t see at all. In these very rare cases, complete blindness means someone cannot see color, shapes, or even light.
Nutritional blindness
Nutritional blindness comes from a severe vitamin A deficiency. Over time, a lack of vitamin A can cause damage to the surface of the eye, leading to poor night vision, color blindness, and more. Left untreated, nutritional blindness can lead to complete blindness.
Congenital blindness
Congenital blindness is blindness someone is born with. Birth defects or inherited conditions like Usher syndrome can lead to complete blindness in infants, and is usually a permanent condition.
How common is blindness in adults?
According to the World Health Organization (WHO) and the National Library of Medicine:
At least 2.2 billion people around the world have some kind of vision impairment.
Of these, 36 million people are blind, with 3.4 million in the United States alone.
Women make up 55% of visual impairment cases.
As many as 1.1 billion people with vision impairments cannot see well simply because they don’t have glasses or access to eye doctors.
What conditions cause blindness?
The most common health conditions that cause blindness include:
Cataracts, cloudy or hazy spots that form on the eye’s lens.
Glaucoma, a group of progressive eye diseases that damage the eye’s optic nerve.
Macular degeneration, an age-related eye condition that affects vision when the macula, the center of the retina, starts to break down.
Diabetic retinopathy, or diabetic eye disease, which occurs when uncontrolled high blood sugar damages blood vessels in the eyes.
Retinitis pigmentosa, a genetic eye disease that causes slow vision loss.
Blindness can also result from injuries, accidents, or infections. In some cases, strokes that affect the parts of the brain that control vision can cause vision loss or blindness.
Is blindness preventable?
Some forms of blindness, like those we’re born with, are not preventable. However, most issues that cause blindness can be prevented.
The best ways to protect your vision and avoid injuries include:
Keeping up with regular eye exams.
Maintaining stable blood sugar and blood pressure levels.
Eating a nutritious, heart-healthy diet.
Wearing protective equipment or face gear when playing sports or working with machinery.
Getting enough exercise.
Educating yourself on your family’s medical history to watch out for possible genetic eye conditions.
Quitting smoking.
Keeping your eyes clean and avoiding infections.
Can a person lose both their hearing and their vision?
Yes. When someone loses both their vision and their hearing, they have deafblindness. Deafblindness affects someone’s ability to communicate, find information, and move around.
It’s rare for someone to lose both their sight and their hearing. In most cases of deafblindness, someone starts with a hearing or vision impairment, then develops the other. In the rarest cases, like a severe stroke or accident, someone can lose their hearing and vision simultaneously.
Where can I get more information about blindness?
To learn more about blindness, see:
Blindness Warning Signs: What Causes Blindness in Children and Adults?
What Do You Do After a Blindness Diagnosis? How to Navigate Your First Steps
To find organizations that support people who are blind, check out Ability Central’s Service Locator tool. This searchable national database of nonprofits can help connect you with a local organization offering medical services, social programs, or other support for people with vision disabilities.
Additional Information
The content provided in this article is for informational purposes only and is not intended as a substitute for legal, medical, or other professional advice. While we strive to provide accurate and up-to-date resources, some information may become outdated or incomplete. Always consult with your provider about personal medical concerns.
