YES! The standard for how a “normal” eye sees is called 20/20 vision. If you can only see 20/70, you will be diagnosed as having low vision. That’s where our IALVS eye doctors can help. We specialize in maximizing remaining eyesight for people with low vision.
20/70, 20/20, 20/40, 20/10… Where do these numbers come from?
Let’s go back a few steps to explain how your eye doctor obtains these numbers.
Visual acuity (VA), is a measurement of your eye’s ability to see shapes and the details of an object at a given distance. It is the typical clinical measurement of visual function and describes the acuteness or clearness of your vision. VA must always be measured using consistent methods of testing in order to detect any visual changes. When your eye doctor performs visual acuity testing, one eye is tested at a time.
To test visual acuity, your eye doctor will position you (either sitting or standing), at a distance of 20 feet (6 meters) from an eye chart. The multi-letter Snellen eye chart is commonly used. You will need to remove your eyeglasses and your eyes will be tested separately.
You will be given a card or stick to cover your eye that is not being tested, and then you’ll need to read the lines of the letter chart. Based on how many of the lines you can read correctly, your eye doctor will record your VA.
What’s the exact meaning of visual acuity numbers?
According to the American Optometric Association, if you can clearly identify a row of 9mm letters while standing at the prescribed 20 feet away, you have 20/20 vision. This is regarded as perfect vision!
- If you have 20/40 vision, it means that when you stand at 20 feet from the chart, you can only see as well as a person normally sees when standing 40 feet away. This is diagnosed as nearsightedness, and prescription eyeglasses can sharpen your vision.
- If you have 20/10 vision, it means your sight is better than the average person! When standing at 20 feet away from the chart, you are able to see what a normal person can see at 10 feet away.
- What about someone who can only see 20/200? That’s the number necessary to be considered as legally blind in the United States. A person with 20/200 has to stand 20 feet away from an object to see it clearly, whereas someone with normal vision could see the same object just as clearly from 200 feet away.
- If you can see 20/2, you are likely not human. This is the VA that some birds, such as hawks, are believed to have. That’s how these natural predators can precisely spot a scurrying mouse from high in the sky.
- To be diagnosed as having low vision, visual acuity is 20/70 or poorer – and cannot be corrected or improved with regular prescription eyeglasses. That means if you stand at 20 feet from the eye chart, you can only see what a person with normal vision can see from 70 feet away.
20/70 or worse? Contact an IALVS eye doctor near you for assistance
If you can only see 20/70, you are officially diagnosed with low vision. We’re here to reassure you that this diagnosis is not a reason to accept that you’ll never do the things you love or enjoy the beautiful world around you again! Our IALVS eye doctors are knowledgeable about a wide range of low vision aids to optimize your visual acuity.
By sharpening your sight, your IALVS doctor can help restore your visual independence and enhance your quality of life. We will assess your remaining vision thoroughly and take the time to understand your lifestyle needs and preferences, all in order to match you with the most appropriate devices for your unique needs. Regain your independence and start doing the things you want to do again.