Is too much screen time damaging your vision?

Susan Coats, optometrist, checks the vision of patient Eileen Bruner at The Optical Shop in Brookings Wednesday afternoon. Coats regularly sees and treats symptoms in her patients that are related to Computer Vision Syndrome. Photo by Charis Prunty/Register

• Lots of work in front of the computer is creating a whole new set of eye problems

BROOKINGS – As more and more patients are learning, when an optometrist or ophthalmologist uses the term CVS, she’s probably not referring to a pharmacy.

The acronym stands for Computer Vision Syndrome, an umbrella classification for multiple symptoms that computer users frequently experience.

Susan Coats, optometrist at The Optical Shop in Brookings, said computers do a lot for us but, because we use them so often, we’ve encountered a whole new set of eye problems. And those problems extend to kids, who often spend great amounts of time staring at one screen or another.

The main symptoms of CVS, Coats said, are eye fatigue, eye strain, trouble focusing on a computer, double vision and a lot of neck and back issues.

"What happens is, our eyes need to generate a different power to focus at different distances,” she said. “To see far away they need one power, and to see up close they need a different power. Well, to see at a computer distance, that's a different power yet.

"A lot of people have maybe no (vision) correction or they have correction that just focuses them for far away or just for up close. Well, the problem with that is the computer is in between – it's what we call intermediate vision.”

A lack of contrast on the screen also throws off your eyes.

“Viewing a computer screen is different than reading a printed page,” says the American Optometric Association. “Often the letters on the computer screen are not as precise or sharply defined, the level of contrast of the letters to the background is reduced, and the presence of glare and reflections on the screen may make viewing difficult.”

Contributing factors to CVS include glare on the computer screen, poor lighting, improper viewing distances, poor seating posture and uncorrected vision problems, the AOA states.

Add to that the fact that, when we’re staring at a screen, we often forget to blink.

"You need a good tear film to focus well,” Coats said. “So, if your tear film isn't healthy or isn't adequate, then we can actually have even more trouble focusing. Again, it all falls under this Computer Vision Syndrome.”

CVS generally sets in when someone spends more than two hours per day on a computer. Discomfort appears to increase with the amount of computer use, the AOA says.

"What a lot of people experience with CVS is they'll say, 'I'm at my computer for this many hours and I look away and then everything is blurry,’” Coats added.

“Well, what's happening is your focusing system, it needs to generate more plus power to see up-close. So, when you're looking up close for long periods of time your eyes kind of get locked into this narrow focusing position. And then when you go to look away they have to relax. Well, some people take a lot longer to relax than others. And the older we get, the harder that is.”

Usually the symptoms will disappear when the person stops computer work. But sometimes, reduced visual abilities such as blurred distance vision are permanent, AOA states.



Head to an eye doctor

To address the vision side of CVS, seeing an eye doctor may be the first step. Even if you already wear glasses, they are usually created for general vision or reading and often don’t help with computer viewing. Even bifocals won’t necessarily work, Coats said, because the top portion is meant for far-away viewing and the bottom for reading. Progressive bifocals do dedicate a portion of their lenses to intermediate distance, so they can be helpful for computer work.

Coats will often recommend a special pair of computer glasses for the intermediate distance. “Office bifocals” may help: The top half is set to see 10-15 feet away while the bottom is set for the intermediate computer distance. People usually sit 20-28 inches away from their computer screens, she said.

Eliminating glare is important, too. Cover up windows, buy light bulbs with lower wattage and station the screen so overhead lights don’t create glare.

Then, look down at your screen. Eyes converge best when they are looking 10-15 degrees downward, rather than straight ahead. And blink – Coats tells her patients to put a little sticky note on the corner of their computer screen reminding them to do just that.

But sometimes the eyes just need a break.

"We call it the 20-20 rule: For every 20 minutes you spend on the computer, you should take a 20-second break looking off into the distance. That's going to help your eyes relax and refocus at that distance target again,” Coats said. "If you're working on the computer for two hours straight, you want to take about a 15-minute break.”

Think about your posture, Coats adds. The AOA says feet should rest flat on the floor when you’re at your desk, and if your chair has arms, they should be adjusted to provide support while you’re typing.



CVS in kids

Kids sometimes put in as much “screen time” as adults these days. Schools regularly use computers – some have even handed out laptops for their students to take to each class. Then there’s Facebook, web browsing and computer games. Not to mention time spent staring at the smaller screen of a phone, where kids are connected to texting, games and even the Internet.

A website called allaboutvision.com reports that the National Eye Institute has found the prevalence of nearsightedness among Americans has increased from 25 percent to 41.6 percent of the population over the past 30 years – an increase of more than 66 percent (among people with 12 or more years of formal education, the prevalence of myopia is now as high as 59.8 percent).

It notes that the amount of time children ages 8 to 18 devote to entertainment media (including computer and video games) each day increased from 6.19 hours in 1999 to 7.38 hours in 2009. In 2009, 29 percent of American children ages 8 to 18 had their own laptop computer, and kids in grades 7 through 12 reported spending an average of more than 90 minutes a day sending or receiving texts on their cell phones.



Screen time glasses

Coats said a nature vs. nurture debate has always surrounded the topic of vision problems in kids. But eyestrain related to “near tasks” such as phone and computer screen viewing can make people more nearsighted than they otherwise would be, she said. She prescribes glasses specifically for screen time for some kids, sometimes even bifocals. And she tells young patients to hold their devices further away from their faces, where the eyes don’t need to work as hard to view them.

We learn through our eyes, Coats said. That’s why, when a patient young or old complains of CVS symptoms, optometrists check the tracking, alignment, posture and positioning of their eyes.

"If any one of those things or several of those things are off balance, it can really cause a lot of problems for reading, Coats said. “Eighty percent of what we learn comes in through our eyes, so we want to make sure they have the best correction available and make sure their eyes are working as well as they can in order to help with the learning process.”

Learn more about CVS by visiting www.aoa.org.



Contact Charis Prunty at cprunty@-brookingsregister.com.