20/20 Vision: Visual Acuity, Testing, and More

Someone with 20/20 vision is considered to have normal visual acuity, or normal eyesight.

About 35 percent of adult Americans have 20/20 vision, which means they can see objects clearly when standing 20 feet away.

20/20 does not denote perfect vision, and there are other designations for people with better vision than 20/20. People with 20/10 vision and 20/5 vision have better eyesight.

Introduction

20/20 is a measurement that denotes clear, sharp and normal vision. The numbers mean that you see objects in focus and in detail at a distance of 20 feet.

Although eye doctors classify 20/20 as normal, it does not equate to perfect vision. Other visual skills, such as the detection of colors and peripheral vision, are equally important. 

Only 35 percent of adults have 20/20 vision without visual aid or corrective surgery. That number rises to 75 percent and includes people who benefit from the help of LASIK surgery, eyeglasses or contact lenses. 

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Visual Acuity & 20/20 Vision

Visual acuity is the most common measurement of how a person’s eyes function. If you have 20/20 vision, it means you can see the same amount of details on an object from 20 feet away, just as a person with average vision clarity. 

How Is Visual Acuity Tested? 

A visual acuity test checks how well a person sees the details of a symbol or letter from a specific distance. Visual acuity refers to a person’s ability to distinguish the details and shapes of things they see. 

However, that is simply one aspect of a person’s vision; others include peripheral vision, color vision, and depth perception. The following are professionals who can perform the test:

• Ophthalmologist
• Optometrist
• Optician
• Technician
• Nurse 

The purpose of this test is to determine whether a person is experiencing vision problems. This test is part of a comprehensive eye exam. The test uses Snellen and Random E. 

Snellen Chart

The Snellen chart is a grid of letters or symbols. It is customary to find this chart in an eye doctor’s office or a nurse’s office at school.

Letters and symbols are different sizes and arranged in columns and rows. Usually each row of letters is a different size than the one above it and below it.

A person stands 14 to 20 feet away to determine how well they can distinguish the letters and shapes, one eye at a time. You cover one eye, and an ophthalmologist will request you to read out the letters you can see clearly with the uncovered eye.

Once done, you will cover the other eye and repeat the same process. The doctor or nurse will ask you to read all the letters on the chart until they no longer can do so. 

Random E Test

You would typically take a Random E test at an eye clinic. The test involves identifying which direction the letter “E” is facing. The doctor displays the letters on a chart or projection, and a person points to whichever direction the letter faces. 

The doctor places the chart through different lenses. This test helps determine ideal contact or eyeglass lens prescription. 

What Does 20/20 Vision Measure? 

20/20 vision measures the clarity and sharpness of a person’s vision from a distance of 20 feet. The designation of 20/20 does not mean perfect eyesight, as other visual aspects contribute to a person’s overall eyesight.

Some people have sight better than 20/20. 

Is Anything Better Than 20/20 Vision? 

Some people have 20/15 vision, and a rare group of others have 20/10 vision. Both designations are considered stronger than 20/20.

20/10 vision means that a person can see clearly at 20 feet, what an average person with 20/20 sees at 10 feet.

20/5 vision is present in most birds of prey, including eagles. It is rare for humans to have such sharp eyesight.

Other Eye Tests to Determine Vision Strength

In addition to the visual acuity test, these are the other exams an eye doctor might take you through: 

• Retinoscopy is a test used to determine an eye’s refractive error. This test identifies whether a person is near or farsighted. 
• A refraction test helps determine a person’s eyeglass prescription. 
• A keratometry test measures the cornea’s shape and curve. It shows how an eye perceives and reflects light. 
• Peripheral visual field exam– take the exam to measure the strength of an eye’s peripheral vision. 
• Intraocular pressure management tests the pressure or force of the fluid in your eyes. 

How to Get 20/20 Vision

There are some ways a person can improve their eyesight to get 20/20 vision. 

• Eat a proper diet rich in vitamins and antioxidants. Vitamins like vitamin C and E, and minerals including zinc, play a role in maintaining eye health. A nutritious diet helps prevent age-related diseases like cataracts and macular degeneration.
• Get visual aids. A person can use surgery, contact lenses or eyeglasses to acquire 20/20 vision. The typical corrective procedure is LASIK surgery.
• Schedule annual eye exams. Doing this helps a person detect any eye concerns early enough. It is not a way to get 20/20 vision, but a way to protect it. Just because a person has always had good eyesight does not mean it cannot deteriorate. 

FAQs 

How far can you see with 20/20 vision?

20/20 vision means that you can see clearly at a distance of 20 feet, which is the standard for “normal” eyesight. At a distance of 20 feet from an object, a person with 20/20 vision sees the object with sharpness and clarity.  

What is the highest vision you can have?

Even though 20/20 is the perfect vision, some people can still see clearly beyond 20 feet. Many young people can see objects smaller than the standard 20/20 size. The highest vision some people can have is 20/10 vision, meaning they can see at 20 feet clearly, while others with normal vision can only see at 10 feet from an eye chart. 

Does 20/20 mean perfect vision?

No. 20/20 vision refers to the sharpness or clarity (visual acuity) measured at 20 feet. It does not consider other essential visual skills such as side or peripheral vision, depth perception, eye coordination, color vision, and focusing ability. A combination of all these visual skills contributes to perfect visual ability. 

References

1. Cataracts. (August 2019). National Eye Institute.

2. Diet and Nutrition. (Retrieved January 2022). American Optometric Association.

3. Laser Surgery Can Improve Vision Problems. (Retrieved January 2022). University Rochester Medical Center.

4. Snellen Chart. (May 2021). National Center for Biotechnology Information.

5. Visual Field Testing. (September 2020). Cleveland Clinic.

6. What is 20/20 vision. (May 2018). The University of Iowa Hospitals & Clinics.

7. More eyes with 20/10 distance visual acuity at 12 months versus 3 months in a topography-guided excimer laser trial: Possible contributing factors. (February 2019). National Library of Medicine.