A common test for visual acuity is Snellen`s eye chart. Someone who is legally blind could simply read the top row of the chart, a capital E, while wearing corrective lenses. The line under the capital E is the line for 20/100. There are also tests that can measure between 20/200 and 20/100. Someone who can`t see the line for 20/100 but sees somewhere between 20/100 and 20/200 would still meet the government`s standard of legal blindness, which is why they are listed as “20/200 or less.” Few people today are completely blind. In fact, 85% of all people with eye diseases have some kind of vision; About 15% are completely blind. A legally blind person with 20/200 vision (with the best corrective lenses) would have to be 20 feet away from an object to see it, and someone with 20/20 vision could see it from 200 feet away. Blind people are “legally blind,” but some people who can see with strong eyeglasses say they are legally blind without their glasses. This means that without glasses, they might not see well enough to see certain things, drive, etc.
Visual acuity below 20/200 is considered blind under the law, but to truly fit the definition, the person must not be able to achieve 20/200 vision, even with prescription glasses. Many people who would be legally blind without glasses can function well in everyday life with proper glasses or contact lenses. Most government agencies and health care institutions agree that legal blindness is defined as visual acuity (central vision) of 20/200 or worse in the best sighted eye or a field of vision (peripheral vision) limited to only 20 degrees. Visual acuity of 20/200 means that what the legally blind person can see at 20 feet, the average person can see clearly at 200 feet. When it comes to the field of vision, the average person can see 140 degrees without turning their head. Another way of looking at it: if someone with 20/20 vision is standing next to a legally blind person, the legally blind person should approach up to 20 feet to see an object from 200 feet away, as well as the person with normal vision. What are the main causes of blindness? According to the National Eye Institute, there are four main causes of blindness in the United States. Striem-Amit E, Gen M, Amedi A.
“Visual acuity of congenital blind persons by visual sensory substitution for auditory. PLoS One. 2012;7(3):e33136. doi:10.1371/journal.pone.0033136 According to the American Foundation for the Blind, blind within the meaning of the law is not the same as completely blind, which is used to describe the inability to see anything with both eyes. Most people who are legally blind have some eyesight. If you have a Snellen rating above 20/70, with and without contact lenses or glasses, you have relatively good vision and are not legally blind or even legally visually impaired. Total blindness describes a complete lack of light and perception of form. In other words, completely blind people cannot see the light and cannot see the shape of anything in front of them. Total blindness is rare – 85% of people with eye diseases have some vision, meaning that only about 15% of people with eye disease go completely blind. An optometrist can diagnose whether a person is legally blind through a standard eye exam using the Snellen diagram — the standard for measuring visual acuity in the United States. Measuring visual acuity and/or visual field can help determine whether a person is legally blind. We have all heard the term “legally blind,” but what does that really mean? How is it different from complete blindness and who is considered legally blind? Against the background of legal blindness, these are the consequences of defects or damage in various ocular tissues.
The eye is a complex organ, and even the smallest tissue damage can significantly affect vision. An estimated 1.1 million Americans are legally blind. Certain conditions, such as glaucoma, cataracts, diabetes, and macular degeneration, can affect your vision to the point where you can be diagnosed with the disease. First, what does it mean to be “legally blind”? In most states, if you have less than 20/200 visual acuity that cannot be corrected with glasses/contact lenses, you are legally considered “severely visually impaired” (which was called “legally blind”). But the trick here is not what you see “naturally” (with the naked eye), but how well you see with your glasses or contact lenses. Despite such a high correction of myopic lens, if one or both of your eyes can see 20/40 or better, you are not “legally blind”. However, it`s easy to see how someone might feel this way when you`ve lost glasses somewhere! To be legally blind, you must meet one of two criteria: visual acuity (visual acuity) and field of vision (the full range of what you can see without moving your eyes). Some government agencies also consider field of view to determine legal blindness.
The field of view is the entire area that a person can see, including their peripheral vision when looking straight ahead. Ophthalmologists express the field of view in degrees, with the normal field of view of each eye covering more than 120 degrees horizontally and 90 degrees vertically. Anyone who has a field of vision of 20 degrees or less, even using glasses or contact lenses, is considered legally blind in some countries. This is also known as “tunnel vision”, which means that the individual has difficulty seeing objects on the left and right sides of their body when looking straight ahead. People often ask about the difference between being blind and being “legally blind.” Because “blindness” can mean many different things, blindness under the law is the threshold at which a person is considered visually impaired for legal purposes, such as insurance purposes, to receive certain benefits, or to be accepted into various programs. Since legal blindness is a legal rather than a medical term, its definition may vary by location. For example, the United States, Canada, and the United Kingdom define legal blindness as 20/200 corrected vision in the individual`s best eye using contact lenses or glasses. With 20/200 vision, the person cannot be more than 20 feet (six meters) away to see what a person with normal vision can see at 200 feet (60 meters). A visual acuity exam is an eye exam that tests a person`s ability to identify the shapes and details of objects presented. Visual acuity is expressed as a fraction. A person with normal vision will have a visual acuity of 20/20.
A person is considered legally blind if a visual impairment limits vision to 20/200 or one-tenth of normal vision. Most of our funding comes from people like you. During 2020, we studied the impact of COVID-19 on people who are blind or partially sighted and advocated for meaningful responses to the pandemic. This work is only possible thanks to donations from people like you. If you appreciate the information you found on our website, make a gift today! For people with legal blindness, different treatment options are available depending on the cause of their visual impairment. However, in some cases, such as retinal degeneration disorders, the symptoms can be treated, but there is no cure. If you are completely blind, you cannot see any light or shape. Among people with eye diseases, only about 15% can see nothing at all. If you are legally blind, you can still see, but not so clearly. Visual impairment, on the other hand, is defined as 20/70 vision in the best eye with glasses or contact lenses.
Although poor vision can interfere with daily activities, vision loss is not as profound as legal blindness. Total blindness is the complete absence of light perception and shape perception and is recorded as “NLP”, an abbreviation for “no light perception”. Like the term “legal blindness,” “visual impairment” is not a functional definition that tells us a lot about what a person can and cannot see. It is more of a classification system than a definition. There are many causes of legal blindness, including accidents, injuries, and eye diseases. The four main causes of legal blindness are eye diseases, namely age-related macular degeneration, cataracts, diabetic retinopathy and glaucoma. While the terms “poor eyesight,” “legal blindness,” and “total blindness” may sound similar, they describe different things. Opticians and government agencies generally define legal blindness as a person who has 20/200 vision in the best eye, even with glasses or contact lenses, indicating a significant vision deficit. You measure your eyesight by wearing glasses or contact lenses. Their vision could fall below 20/200 without them. If it improves when you put on your glasses or contact lenses, you are not considered blind under the law.
If a visual impairment reduces visual acuity to 20/200 or one-tenth of normal vision — which is 20/20 even with glasses or contact lenses — a person in North America is considered legally blind. Note that the blind person within the meaning of the law is not completely blind. While legally blind people can still technically see, completely blind people will not be able to perceive light or see anything.