What is 20/20 Vision?

Eye Chart over woman's face

Have you ever heard someone say they have 20/20 vision? What does that mean exactly? In this post, we’ll discuss what 20/20 vision is, the reasons for blurry vision, and ways to improve your vision.

What is 20/20 vision?

20/20 vision is a term used to describe normal visual acuity, which means that a person can see a standard-sized letter or object from a distance of 20 feet away. This is based on the Snellen eye chart, which is used to test a person’s visual acuity. If someone has 20/20 vision, it means they can see what a person with normal eyesight can see from 20 feet away.

What is 20/200 vision?

A person with 20/200 vision can see at 20 feet away what a person with normal eyesight can see at 200 feet away. In other words, someone with 20/200 vision would need to be 20 feet away from an object to see it as clearly as someone with normal vision can see it from 200 feet away.

What does “Legally blind” mean?

The term “legally blind” is used to describe a level of visual impairment that meets specific legal criteria for benefits and services. In the United States, a person is considered legally blind only if they have a visual acuity of 20/200 or worse in the better eye with the best possible correction or a visual field of 20 degrees or less in the better eye. 

It’s worth noting that some individuals may claim to be legally blind without considering the use of corrective lenses. However, if that person can achieve better than 20/200 vision in one eye with glasses or contact lenses, they are not considered legally blind.

Being legally blind means having very impaired vision, making it challenging to complete everyday tasks that require sight, such as reading, driving, cooking, or recognizing faces. Nevertheless, it’s important to recognize that visual impairment is a spectrum and many individuals who are legally blind still have some functional vision. With the help of visual aids, mobility training, and other accommodations, people with visual impairments can still lead independent and fulfilling lives.

Reasons for blurry vision

There are several reasons why a person may experience blurry vision. Some of these include:

Refractive errors: These are the most common cause of blurry vision. Refractive errors occur when the shape of the eye does not allow light to focus properly on the retina. The most common refractive errors are myopia (nearsightedness), hyperopia (farsightedness), and astigmatism.

Age-related changes: As we age, our eyes undergo changes that can affect our vision. For example, presbyopia is a condition that occurs when the lens of the eye becomes less flexible, making it harder to focus on close-up objects.

Eye diseases: Certain eye diseases, such as dry eye, keratoconus, cataracts, glaucoma, and macular degeneration, can cause blurry vision.

Environmental factors: Exposure to too much sunlight, dry air, and certain chemicals can cause blurry vision.

Ways to improve vision

There are several ways to improve your vision, including:

Corrective lenses: Glasses or contact lenses can correct refractive errors and improve your vision.

Surgery: Refractive surgery, such as LASIK, can correct refractive errors and eliminate the need for glasses or contact lenses.

Healthy lifestyle habits: Eating a balanced diet, exercising regularly, and avoiding smoking can also improve your overall eye health.

In conclusion, 20/20 vision refers to normal visual acuity, meaning a person can see a standard-sized letter or object 20 feet away. Blurry vision can be caused by several factors, including refractive errors, age-related changes, eye diseases, and environmental factors. There are several ways to improve your vision, including corrective lenses, surgery, eye exercises, and healthy lifestyle habits. If you’re experiencing blurry vision, it’s important to see an eye doctor for a comprehensive eye exam to determine the cause and get the appropriate treatment. 

If you’re experiencing blurry vision caused by refractive error or a corneal disease such as keratoconus, the Cornea and Laser Eye Institute is here to help. Our clinic is the leader in the field, and our team of expert doctors has written numerous book chapters, journal articles, and publications. We’ve also taught and mentored numerous doctors and given thousands of hours of lectures on the latest techniques and technologies in the field of ophthalmology.

Our clinic specializes in the treatment of various eye conditions that can cause blurry vision. Our team of Harvard-trained refractive surgeons performs all forms of refractive surgery, and our world-renowned contact lens specialists are here to help you find the best solution for your needs. If refractive error is the cause of your blurry vision, our experts can perform LASIK, PRK, Evo ICL, and RLE surgery or nonsurgical options such as contact lenses and orthokeratology. If keratoconus is the cause of your blurry vision, our experts are here to provide you with the latest treatments, including corneal cross-linking, TGPRK, CTAK, scleral lenses, and more. We are dedicated to helping you manage this condition and preserve your vision. If cataracts are the culprit behind your blurry vision, our team is well-versed in cataract surgery. Our state-of-the-art equipment and techniques ensure that your surgery is safe, effective, and tailored to your individual needs. If your blurry vision is caused by corneal disease, dry eye, or ocular surface disease, our doctors are experts in the latest treatments and technologies. We can help you manage these conditions and improve your vision. At the Cornea and Laser Eye Institute, we’re committed to helping you see the world clearly again. Visit our clinic today and experience the expertise and dedication of our team firsthand.

20/20 vision a term used to describe normal visual acuity — the sharpness of a person’s vision — measured at a distance of 20 feet. If a person has 20/20 vision it means that they can see clearly at 20 feet what should normally be seen at a distance. If someone has 20/100 vision it means that they must be as close to 20 feet as possible to see what a person with normal vision could see at 100 feet.

The Snellen Eye Chart is a test that is used to measure a person’s distance visual acuity. The chart contains rows of letters, numbers or symbols printed in standardized graded sizes.

20/20 doesn’t necessarily mean that you have perfect vision, it only indicates that the sharpness or clarity of your vision at a distance. There are other important visual skills such as peripheral awareness, depth perception, eye coordination, color vision, and focusing ability that contribute to your overall visual ability as well. Some people can see very well at a distance, but are unable to focus on objects that are close to them. This condition can be caused by presbyopia (loss of focusing ability) or hyperopia (farsightedness). Other people can see items that are close, but not those that are far away. This is known as myopia (nearsightedness). A comprehensive eye exam can help to determine if there is anything that is affecting your ability to see well.

Fun facts regarding visual acuity:

  • The Snellen Eye Chart was created in the 1860s by Dutch eye doctor, Herman Snellen. There have been other charts that have been created that might also be used during an eye exam such as the Tumbling E Chart. The Tumbling E Chart features capital letter E’s facing in different directions. This chart comes in handy when examining children who don’t yet know the alphabet or for people who aren’t familiar with the English language and alphabet. Rather than say a letter, they can pick the smallest line of E’s that they can see, and say or point to which way the “arms” of the E in that line are facing. Numerous studies have shown that this chart and the Snellen chart come up with nearly the same results.
  • Around 1 million aged 40 and older in the United States are considered to be legally blind.
  • To obtain a driver’s license in the US, you need to have at least 20/40 vision or better.
request a free consultation
request appointment
contact us