20/20 Vision for 2020

Created by Dominika Śmiałek, MD, PhD candidate
Reviewed by Bogna Szyk and Jack Bowater
Based on research by
Bénédicte M. J. Merle, Gwendoline Moreau, Anna Ozguler, Bernard Srour, Audrey Cougnard-Grégoire, Marcel Goldberg, Marie Zins & Cécile Delcourt Unhealthy behaviours and risk of visual impairment: The CONSTANCES population-based cohort Scientific Reports - Nature (April 2018)
Last updated: Jun 05, 2023

Imagine a day without scrolling through your phone, watching Netflix, or having to read road signs while driving somewhere. Sounds tough (and even a little dangerous), right?

Around 2.2 billion people worldwide have some form of vision impairment. What's even more frightening is that almost 50% of cases could have been prevented. In the USA, the number of visually impaired people is said to double by 2050. This enormous increase is due in part to us spending more and more time in front of screens, both at work and at home.

As WHO stated in their resolution on February 6, 2020, early detection and prevention are essential if we want to reduce blindness and visual impairment. Their recommendations highlighted that lifestyle choices are a preventable factor. The American people's lack of knowledge about eye health may be putting their vision at risk, according to a survey released by the American Academy of Ophthalmology. With our calculator, you can see how your lifestyle affects your eyesight. We won't leave you with meaningless figures either - you'll find some advice on what you can do to make your eyes healthier. For more details on how the calculator works, take a look at the article below.

We try our best to make our Omni Calculators as precise and reliable as possible. However, this tool can never replace a professional doctor's assessment. If any health condition bothers you, consult a physician.

20/20 vision? What does that even mean?

20/20 vision means that you can see perfectly from a distance, without the need for glasses. This original notation comes from the Snellen board, used to test your visual acuity.

Snellen chart

Remember at the ophthalmologist, you'd be told to read from those boards where the letters on them gradually get smaller and smaller? A 20/20 score means that you can read the optotype 20 from 20 feet away (around 6 meters). In our calculator, we refer to vision impairment as 20/40 vision acuity. This means that for a person who can read something perfectly from 40 feet away, this level of visual impairments means you would have to be 20 feet away.

What about the diopter conversion? You'll find the solution in the table below:


Snellen score













Can I see any better than 20/20?

Some people see much better than what we consider normal vision. In that case, their result maybe 20/10. That means they can see from 20 feet what the average healthy person sees from only 10 feet away.

People this eagle eyed tend to end up as pilots or athletes (Olympic medalists!), and comprise about 1% of the total population. Interestingly, the difficulty in estimating this number of people comes from the fact they rarely visit the ophthalmologist - after all, they don't need to. The structure of our eye limits the maximum visual acuity to 20/5. In a large number of children, a result of 20/15 is typical.

Why does my vision get worse every year?

Generally speaking, physiological sight deterioration is related to age. However, young people often develop myopia, particularly if they have genetic predispositions (e.g., their parents have a major visual impairment) or if they grow too fast. In the second scenario, the eyeball does not keep up with the growth of the rest of the body and becomes too short. This tends to be temporary though; the eyeball catches up once the kid stops growing.

For adults, however, there are two independent phenomena that can occur:

  1. After the age of 40, lenses lose their capacity for accommodating various shapes and become less flexible. The effect? Your close-up vision gets worse. It doesn't matter if you have had myopia or hyperopia before, the effect is still the same.
  2. After 70, due to changes in light refraction within the eyeball, vision deteriorates by +1.5 dioptres, and by +2.5 dioptres by the time you reach 80. Fortunately, if you are shortsighted, your defect 'retreats' by the same magnitude.

Other conditions that are more likely to affect the elderly, such as diabetes and hypertension, do not contribute to good visual acuity either.

A scheme of an eye with presbyopia

Use of the calculator - a short guide

This Omni calculator is based on the findings of CONSTANCES cohort, a prospective cohort study of almost forty thousand members from the general adult population in France.

Let's go through step by step what is required for a result:

  1. Screen time - use of digital screens, such as computers, tablets, telephones, leads to eye and vision-related problems. Prolonged exposure, with no breaks, is particularly harmful. Choose how many hours a day you spend in front of a screen.

  2. Activity - 1 to 3 points are given for each answer.

Look at the first field - the question concerns the level of activity that goes with your job. If you are retired, select the option that most closely corresponds to your last job.
* Cycling, hiking, walking - this question refers to regular, longer hikes, cycling trips or walks.
* Household activities - such as house cleaning, gardening. Again, how much time you spend during the week doing this.
* Gym, team sports - this is all about being active in your free time - team games, running, cardio exercises all count. Choose how many hours a week you spend dloing such things.

  1. Diet - studies show that a Mediterranean diet (MedDiet) is linked to healthy eyes, so the calculator evaluates your diet against one; between 1 and 5 points are given in each category
    • On top there are fruit, vegetables, and legumes, which have a positive effect on your eyes. Below them are some more eye-protecting products, fish and cereals.
    • White and red meat, as well as dairy products, have an unfavorable effect on your body, and according to the MedDiet ideology, their consumption should be limited.
    • Olive oil - daily use is highly recommended.
    • Alcohol - Some is recommended, but in moderation - none is as unhealthy as over 7 cups a week.
  2. Smoking - first, choose if you have ever smoked. Unfortunately, any history of smoking increases the risk of vision impairment.
    • If you smoke, think about quitting (as soon as possible, smoking damages not only your vision but also your lungs, heart, and increases the risk of cancer!). Please check out our lung cancer risk calculator. Whether you still smoke or already quit smoking, choose how many cigarettes you smoke (or smoked) a day for how many years.

And so in practice, what can I do to keep my sight going?

It might sound trivial, but start moving. You probably won't change your job (81% of office workers spend between four and nine hours a day sitting at their desks). As the job makes up about 30% of your time, the next 30% is sleep - it is worth making sure that you spend your free time actively. Doctors advise regular trips or cardio activity, preferably longer than 2 hours a week. The same goes for daily chores that we don't notice. Housework, gardening - all of this benefits your eyesight and cardiovascular system. Please use our CVD risk calculator.

As for the time you spend in front of screens, we know how hard it is to limit it with today's lifestyle. That's why it's useful to bear in mind a simple trick: 20-20-20. That is, every 20 minutes look at an object that is 20 feet away from you for 20 seconds.

How a person with myopia sees without glasses.
How a person with myopia sees (By gerlos, CC BY-ND 2.0

As we have already mentioned several times, you have to quit smoking. There is no "but." There are better ways to deal with stress or socialize with friends. Tobacco harms practically every single one of your organs. If it's not your first time making this resolution, consider nicotine replacement therapy, or go to a physician.

When it comes to diet, try to eat more cereals, legumes, and, of course fruit and vegetables. Cut down on meat, reducing the consumption of red meat in particular will help our planet. Please check our our meat footprint calculator. And on top of all of that, olive oil. Lots and lots of olive oil! Not only does it contain antioxidants, but also good fats, called monounsaturated fatty acids. In Mediterranean countries, raw olive oil makes up the basis of all of their meals (including breakfast!).

As for alcohol, you can have a small glass of wine with dinner. Just remember to be modest; it is best to not to exceed around three glasses of wine per week.

Dominika Śmiałek, MD, PhD candidate
I want to
improve my eye health
Screen time 💻
Extended use of digital screens in up to 90% of users causes eye and vision-related problems.
I spend in front of a screen
3-6 hours per day
Activity 🏃
Regular and diversified exercises reduce the risk of vision impairment.
💼 How active are you at work?
Moderately active
🏡 Household activities
Less than two hours/week
🚲 Cycling, hiking, walking
Less than two hours/week
⚽ Gym, team sports
Less than two hours/week
Diet 🍲
A Mediterranean diet is associated with a lower risk of vision impairment.
🍅 Vegetables, fruits and legumes
🐄 Red and white meat
🌾 Cereals
🐟 Fish
🍼 Dairy
🔸 Olive oil
🍷 Alcohol
Smoking 🚬
Smoking directly accelerates major causes of severe visual impairment.
Do you smoke?
No, I have never smoked
Based on your score, you lead a healthy lifestyle, which does not increase the risk of vision impairment.
Example: We define vision impairment in terms of visual acuity , e.g. 20/40. An eyesight of 20/40 means that you need to be 2 meters from a road sign to see it, instead of the usual 4 meters.
Health tips 👀
A balanced diet, regular exercise and not smoking are the keys to health, part of which is good vision.
✔️ Screen time - it's good that you don't spend too much time in front of digital screens. Take care of your eyes with this simple trick:
➡️ Follow the 20-20-20 rule; every 20 minutes, take 20 seconds to look at something that is 20 feet away.
✔️ Activity - you're doing well, but there are some things you could improve:
➡️ Nice, you regularly go hiking, cycling, or even for a long stroll🚲. It doesn't have to be the Tour de France, but try to make them a bit longer than your current 2 hours per week.
➡️ Cardio and team sports every week must feel sooo good 😄 It'd be even better if it was more than 2 hours in a week.
➡️ Given the result of your household activities , we'd all like to learn your quick clean-up secrets 😍. Still, how about extending it to more than 2 hours a week?
Do you want some more information on the risks?
Check out 11 similar general health calculators ⚕️
BASDAI scoreBeighton scoreBerg balance test… 8 more
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