A visual field is the range of sight that we have without moving our eyes, in order to be considered legally blind you must have a visual field of 20 degrees or less. This change in the field of our vision is commonly referred to as tunnel vision. Like visual acuity, this is determined based on your best eye.
This begs the inquiry “What vision is legally blind?”
Normal vision is 20/20. That means you can clearly see an object 20 feet away. If you’re legally blind, your vision is 20/200 or less in your better eye or your field of vision is less than 20 degrees.
Also, what is the difference between normal vision and legally blind vision?
One way to think about this is if you’re legally blind, you can still see — just not that clearly. Normal vision is 20/20. That means you can clearly see an object 20 feet away. If you’re legally blind, your vision is 20/200 or less.
What is blindness?
Blindness begins with vision that is so bad that it interferes with an individual’s daily activities.
Why do people have a blind spot in vision?
Having a blind spot in each eye is a natural occurrence and is typically not cause for concern. It occurs because of the structure of the eye and a lack of photoreceptors. You’re likely not even aware of your blind spot in day-to-day living, because your brain fills in any missing information.
One of the next things we wondered was; what is the blind spot of the retina?
You see, this is the blind spot or scotoma of your retina. If you close your left eye and stare at the dot with your right eye, and repeat the test, the plus sign should vanish in the blind spot of your other eye.
The blind spot is the location on the retina known as the optic disk where the optic nerve fiber exit the back of the eye. The optic disk is approximately 1.5 millimeters or 0.06 inches in diameter. In addition to being the point where the optic nerve exits the eye, it is also where the major blood vessels enter to provide blood flow to the eye.
Even if you close one eye, the blind spot is almost impossible to detect. This is because your brain is so adept at providing the missing visual information so that you never notice that small gap in your visual field.
While your brain usually fills in the missing information so that you don’t notice it, this quick and easy test makes it possible to demonstrate the blind spot. Open this image in another browser window. Start by covering your left eye and looking at the star shape with your right eye.
What is the visual acuity of legally blind people?
However, some legally blind people have visual acuity better than 20/200 but their peripheral vision is poor. People with normal vision have a lateral field view of almost 180 degrees. This means that they can see objects located directly to their left or right at the same time.
The U. S. SSA uses the term “legally blind” in people whose vision is 20/200 with glasses or contacts, or whose visual field is 20 degrees or less than the normal eye. This makes “legally blind” people eligible for tax exemptions and disability benefits.
To be considered legally blind, you would have to meet one of these two criteria: Your visual acuity is 20/200 or worse in the eye you can see out of the best. Visual acuity refers to how close a person needs to be to an object that’s 20 feet away in order to see it in detail. Normal vision is measured as 20/20.