What is 20/20 Vision? How to Convert Diopters to a 20/20 Measure

Copyright © Rebecca Turner

We all hear the term 20/20 vision thrown about to mean anyone who has healthy eyesight. But what does it mean? And how does it convert to the lens prescription your optometrist gives you, measured in diopters? By the end of this article you'll be an expert on the definition and understanding of 20/20 eyesight.

What is 20/20 Vision?

The average human being with healthy eyesight has 20/20 focus. This is a benchmark measure of what you should be able to see at a distance of 20 feet.

This measure only really becomes important when people stray from the norm. For instance, if you have 20/100 vision, it means that other people can see clearly from 100 feet away, what you can only see at 20 feet. It's a big disadvantage.

Can You Have Better Than 20/20 Eyesight?

Yes, it is possible for some people. Having 20/20 focus is merely the average visual acuity for a healthy human being. But there is nothing stopping some people from being above average and gaining better than 20/20 vision.

Some fighter pilots claim to use eye exercises to attain 20/10 vision, while the World Record belongs to a man naturally achieved 20/8 focus by training his eyes for better vision. Incidentally, eagles have natural vision of 20/2 - hence the expression eagle eye, which means an exceptional eye for detail.

What are Diopters?

If you have poor eyesight (anything worse than about 20/40 vision), your optometrist will write you a prescription. This describes, in a measure called diopters, the refractive power of your new glasses or contact lenses.

You will get a separate diopter value for each eye, because often one eye is slightly weaker than the other. If the measurement has a minus (-) before it, you are nearsighted and have trouble seeing things in the distance. If there is a plus (+) before it, you are farsighted and have trouble seeing things up close.

However, scientific studies have found that wearing prescription lenses weaken the eyes by forcing them to adapt to the lens. You have probably noticed this yourself when you get a stronger pair of glasses. The world appears ultra-clear and you have to get used to the strong lenses. Then, within days or weeks, they feel normal and eventually are too weak altogether.

Therefore, people with poor vision should attempt to reduce their dependancy on corrective lenses if they want to help prevent further deterioration. If left untreated, bad vision can lead to more serious complications later in life. So if at all possible, it's especially important that you take action to save your vision now. I was able to significantly reduce my prescription and dependancy on glasses with eye exercises by Rebuild Your Vision - click here to read my full review.

How to Convert Diopters to 20/20 Vision

While the 20/20 vision system measures how well you can see compared to a the healthy benchmark, diopters measure the focusing power of your glasses. There is a relationship between the two, shown in the table below. This gives you a very rough conversion between diopters and the 20/20 measurement - but bear in mind there is a lot of variation between individuals.

*Higher diopter values are harder to calculate because it depends on the person - some sources cite a whole range between -4.00 and -6.00 to reflect 20/400 vision. So, these figures are an approximation. Note how the 20/20 measure doesn't increase consistently, and may actually increase exponentially beyond -6.00 (severe myopia).

How Eye Exercises May Help Improve Vision Naturally

I suffered from myopia and astigmatism for 15 years when I discovered eye exercises and my ability to retrain my eyes naturally. I began the Rebuild Your Vision course and began noticing clearer vision within three days. When I next visited my optometrist I was delighted to see that my -3.25 / -3.00 prescription (about 20/150) had been cut to -2.25 / -2.00 (about 20/80 vision) in six weeks. And that was just the beginning.

Eye exercises are the best kept secret in optometry. It's such a tragedy that we are brainwashed into wearing lenses (which may make your eyes weaker) or having eye surgery (which may permanently damage the cornea). Instead we should be encouraged to try this cheaper, safer and more natural method of vision improvement to create better, sharper vision.

Read My Full Rebuild Your Vision Review Here