Eye Doctor: Computers Don't Worsen Vision

May 6, 2014
Originally published on May 6, 2014 3:48 pm

A study out of Australia finds that adults spend more time in front of a screen than they do sleeping. The 1,500 people surveyed spent an average of nine hours per day in front of a television or computer.

What effect does that much screen time have on the eyes? Here & Now’s Jeremy Hobson asks Dr. James Sheedy, who says long hours spent staring at a screen with poor lighting around the screen can cause eye strain, but computers themselves do not worsen vision.


  • James Sheedy, optometrist and professor at Pacific University in Oregon.
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It's HERE AND NOW, from NPR and WBUR Boston. I'm Jeremy Hobson.

And a new survey from Australia finds that adults spend more time in front of a screen than they do sleeping. So what does that do to your eyes?

James Sheedy is professor of optometry at Pacific University in Forest Grove, Oregon, and head of the Vision Performance Institute. Professor Sheedy, welcome.

JAMES SHEEDY: It is my joy to be here.

HOBSON: Well, how much of a problem is it for us to be looking at screens all day, something we were not doing to this extent many years ago?

SHEEDY: Yes, you know, it is not natural to be viewing these screens all day long. And many people have eyestrain problems related to it. We have actually divided eyestrain into two types. There's a dry, irritated feeling that you get on the front surface of the eye. And then there's also an ache or a pain that is felt inside of the eye.

HOBSON: And what causes that, exactly?

SHEEDY: The external one, or the irritation on the front of the eye, is actually due to a decreased blink rate and a subsequent drying of the eye. The other one, the ache or a pain felt inside of the eye, is due to improper functioning of the eye functions, such as convergence and accommodation - that is the focusing of the eye.

HOBSON: Is there a difference between looking at a computer monitor or TV screen and looking at your phone?

SHEEDY: There are other problems that occur when viewing your computer. And one, for example, is a dry eye problem. And that is caused by a decreased blink rate, which also happens when you read a book. But the problem with a computer is that you've got a decreased blink rate, but you are also looking fairly high in the environment, with a fairly wide open eye, thereby exacerbating the amount of tear evaporation that goes on.

HOBSON: You mean instead of lying down and reading your book or sitting in a chair and looking down and reading it, you're looking straight ahead.

SHEEDY: Yes. There's really nothing about the computer, per se. You know, many people are concerned that there's something emanating from their computer that's causing problems for their eyes. And that's not really the case. It is the use of the computer. When we read, we don't blink as much. And when we read from a computer we tend to be looking straight ahead, rather than down.

HOBSON: OK. Well, let me ask you for some practical tips here, because, as you say, eyestrain is a problem for people who are spending a lot of time looking at screens. What are some things that we can do to avoid that?

SHEEDY: Well, first of all, a common problem is a person who's wearing bifocals or progressive addition lenses. Those lenses are designed for downward viewing and a viewing distance of about 16 inches. The computer display tends to be farther away and higher in the field of view. So if you are wearing bifocals lenses or progressive addition lenses, and you're getting neck ache or back ache or you're noticing that the text is blurred, then you should see your eye doctor in order to obtain better glasses for that task.

HOBSON: OK, that's one thing. I know you also talk about the 20/20/20 rule. What is that?

SHEEDY: 20/20/20: every 20 minutes look away at least 20 feet for 20 seconds. Give your eyes a break. We all know that, you know, continuous work deserves a break.

HOBSON: All right, and evaluate the lighting. That's on your list.

SHEEDY: Lighting is probably the second most common culprit. The problem is bright lights in your peripheral vision. And I encourage people to look at their computer display and then use their hand, as if it were a baseball cap visor, to block the lights from their eyes. And if you notice a small, immediate sense of improvement, then those lights are contributing to the discomfort that you are receiving.

HOBSON: That's James Sheedy, professor of optometry at Pacific University in Forest Grove, Oregon.

Professor, thanks so much.

SHEEDY: It has been my pleasure, Jeremy.

HOBSON: And this is HERE AND NOW. Transcript provided by NPR, Copyright NPR.