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What Is 20/30 Vision? (And is It Bad?)

Dr. Jordan Marr

Written By:

Dr. Jordan Marr

Updated: 03 October 2022 •  

Having 20/30 vision simply means that from 20 feet away, you can see what the average person sees from 30 feet away. This means that you need to move 10 feet closer to an object than someone with 20/20 vision.
 
This is called your distance visual acuity and is measured using a visual acuity chart (such as a Snellen chart) during an eye examination. Typically, you will be asked to read lines on the chart from 20 feet (6m) away. Each line of letters has a visual acuity measurement written next to it, and the lowest line that you can read will be your visual acuity (in this case it would be 20/30).
 

Is 20/30 Vision ‘Bad’?

While 20/20 vision is below average, it does not necessarily mean that you have “bad” vision. The World Health Organisation (WHO) considers 20/30 vision to be “near-normal vision”, however most people’s vision can be corrected to 20/20 using glasses.
 
To put things into perspective, the USA considers those with 20/200 vision or worse to be legally blind. This means that from 20 feet away, your vision of an object is as clear as it is for someone with “normal” vision standing 200 feet away.
 

How Does 20/30 Vision Compare to 20/20 or “Normal” Vision?

20/20 vision is considered “normal” or average vision. If you have 20/30 vision, it means that you need to move 10 feet closer to an object to see the object as clearly as someone with 20/20 vision.
 
20/30 vision is a measure of your distance visual acuity (VA). This means that you can still have great reading vision while having 20/30 vision.
 

Do You Need Glasses for 20/30 Vision?

Many distance tasks are affected by having 20/30 vision. This is because your ability to distinguish details from a distance is impacted. Some tasks that can be made more difficult with 20/30 vision include:
 

  • Driving
  • Telling colors apart
  • Working some jobs – such as the police force, or pilots
  • Watching television

 
While a slight glasses prescription will often be able to correct your vision from 20/30 to 20/20, it is not always necessary. Household tasks can be completed easily with 20/30 vision, and reading is typically unaffected.
 
If you have 20/30 vision it is recommended to get distance glasses.
 
It is important to consider that while most cases of reduced vision can be corrected with glasses, sometimes 20/30 vision cannot be corrected. This is the case if you have an eye condition, such as:
 

  • CataractsThis occurs when the lens in your eye becomes cloudy, causing blurred vision and reduced contrast sensitivity. Usually cataracts are age-related, however they can also be caused by trauma or medications. You can also have a congenital cataract, which is something you are born with.
  •  

  • GlaucomaThis eye disease can cause damage to your optic nerve (supplies your brain with visual information). Glaucoma leads to progressive vision loss and even blindness..
  •  

  • Age-related macular degeneration (AMD)This eye disease occurs in the elderly population and causes blurred central vision. AMD causes damage to the macula, which is the part of your retina (light-sensitive layer in the back of the eye) that focuses light to provide clear vision.
  •  

  • Amblyopia (lazy eye)This is when one eye has poor vision caused by poor communication between the eyes and the brain. This is a condition that starts in childhood and over time the “good” eye becomes stronger, and the “bad” eye becomes weaker.
  •  

  • Retinitis pigmentosaThis condition causes retinal cells to break down over time, resulting in vision loss.

 

How Common is 20/30 Vision in Adults?

It is quite common to have a visual acuity of 20/30 or worse, with approximately 1/3 of adults 40 years or older requiring distance glasses in the USA.
 
Some studies suggest that only 35% of the adult population in the USA have 20/20 vision without glasses, contact lenses, or corrective surgeries. With correction, roughly 75% of adults can achieve 20/20 vision.
 

What About 20/30 Vision in Children?

Vision in children is a bit more complicated, as vision is not fully developed at birth. As children get older their vision gradually improves as their eyes develop and grow (this process is called emmetropization).
 
It is expected that that by 5 years of age, children should have 20/30 vision, and at the age of 7 or 8 years old they will reach 20/20 vision.
 
It is important to consider that even with 20/20 vision, your child may experience vision-related problems. Other important vision skills for reading and learning include:
 

  • Eye focusingBeing able to maintain clear vision when the distance of objects changes. This includes looking up at the board and back down at their work.
  •  

  • Eye trackingThis is being able to follow a target, such as following a moving ball or reading words in a line.
  •  

  • Eyes working togetherThe ability of both eyes to work together to see clearly and perceive depth.
  •  

  • Hand-eye coordinationUsing visual information and motor skills together, such as when drawing a picture or hitting a ball.
  •  

  • Visual perception Being able to understand and copy letters, words, and numbers.

 

Understand Your Visual Needs

It is important to have comprehensive eye examinations every 1-2 years or as recommended by your eye doctor. After each examination, your optometrist will explain your prescription, visual acuity, and whether you need glasses to improve your vision. You can also request a copy of your prescription so you can purchase glasses from wherever you would like.
 
For more information on reading and understanding your prescription, be sure to check our article on how to read your eyeglass prescription.
 

References

  • “Low Vision and Vision Rehabilitation”, American Optometric Association
  •  

  • “Cataracts”, Mayo Clinic
  •  

  • “Glaucoma”, Healthline
  •  

  • “Age-Related Macular Degeneration (AMD)”, National Eye Institute
  •  

  • “Amblyopia”, National Eye Institute
  •  

  • “Retinitis Pigmentosa”, National Eye Institute
  •  

  • “The prevalence of refractive errors among adults in the United States, Western Europe, and Australia”, Archives of Ophthalmology
  •  

  • “What is 20/20 vision?”, University of Iowa
  •  

  • “Vision Development: Childhood”, American Optometric Association
  •  

  • “School-Aged Vision: 6 to 18 Years of Age”, American Optometric Association
Dr. Jordan Marr

Written by:

Dr. Jordan Marr

Dr Jordan Marr has over 5 years of clinical and academic optometry experience and is a visual science editor for the Clinical and Refractive Optometry journal. He is licensed under the Optometry Board of Australia.
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