What does it mean to have 20/20 vision?

The year is 2020, so try this one on for size: Only 35% of people naturally have 20/20 vision without glasses, contacts or eye surgery.

That's according to National Health and Nutrition Examination Survey.

20/20 vision means a person can see at 20 feet what someone with normal vision is supposed to see at 20 feet. As the second number in 20/20 increases, visual acuity decreases

For example, said Dr. Joseph Calderone of Better Vision New Jersey in Cranford, if someone has 20/50 vision, which is the minimum allowable vision for driving in New Jersey, that person would see at 20 feet what a person with normal vision could see clearly at 50.

If someone does not have 20/20 vision, an eye doctor needs to figure out if it's a problem with the cornea lens, retina, optic nerve or the brain. If the problem is that the light is simply out of focus, all that is needed is optical assistance such as glasses or contact lenses to improve vision.

Calderone said hundreds of years ago in the western world, people would use pieces of glass to read The Bible better. Then centuries later, inventor Benjamin Franklin put two lenses together in the same frame so people could see both near and far.

Fast forward to 2020, and there are now glasses made with thinner and lighter lenses so that even stronger prescriptions are not heavy. There are progressive lenses or bifocals without lines that eliminate most of the shortcomings of Franklin's original invention. For glasses outdoors, there are polarized glasses and transitional glasses that darken automatically in sunlight, eliminating the need for an extra pair of prescription sunglasses.

Calderone said contact lenses were first hypothesized by inventor Leonardo da Vinci. In the 1880s, the first glass contact lenses were developed. Two Czech chemists developed the first soft plastic contact lenses in 1959, which the company Bausch and Lomb introduced as the first FDA approved soft contact lenses in 1971.

Now, in 2020, contact lenses can be manufactured in such a way that allows them to be disposable on a daily basis. That means a person can wear a fresh pair of sterile lenses every day.

"We've got multi-focal contact lenses enabling some people to see distance and near without reading glasses and we even have transition contact lenses which get darker when you go out in the sun, reducing your need for sunglasses," Calderone said.

Lasik and cateract surgeries have also helped improve peoples' vision over the years. Calderone said the FDA has eye doctors tell patients they have a 90% chance of seeing 20/40 or better, but Calderone said eye doctors can do much better than that in Lasik.

In cateract surgery, there are so implants that can be used to help people with astigmatism avoid wearing glasses or reading glasses.

But Calderone wants people to understand that 20/20 does not mean perfect vision. While many people with 20/20 vision see very well, it is still possible to have issues like poor color vision, close-up vision or peripheral vision.

He said there are lots of choices to help one see better in the year 2020.

"As long as you visit with your eye care professional for regular visits, you can keep your vision healthy and clear," Calderone said.

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