For Christine Wildsoet, a professor of vision science and optometry at the University of California–Berkeley, the coffee shop hosts some of the worst offenders. There are the new moms chatting while their babies are parked in front of iPads, and the dads reading while their toddlers play games on cellphones.

“I just don’t know what the implications of new technology [are] going to be” on kids’ eyesight, says Wildsoet, who studies myopia, or nearsightedness, a condition experts say is beginning earlier in life, worsening later in life and rising to epidemic levels worldwide.

“There’s a major lifestyle shift that’s been brewing over the last 30 years,” including kids and adults doing more close-up work and spending more time indoors, says Mark Jacquot, clinical director of vision care at LensCrafters. “This is contributing to a reduced ability to focus on things farther away, which is essentially myopia.”

In the early 1970s, about 25 percent of 12- to 54-year-old Americans were myopic. By the 2000s, more than 41 percent had the condition, research finds. Wildsoet and her team have trouble finding non-myopic controls for their studies, and clinicians like Maria Liu, head of Berkeley’s Myopia Control Clinic, see children as young as 4 with severe myopia.

Other countries, particularly those in East Asia where schooling starts earlier and lasts longer each day, have beat us to the chase. In Singapore, for one, the military realized it could no longer rule out recruits due to nearsightedness; there would be too few prospects left. It’s since offered laser eye surgery to members and dedicated impressive resources to myopia research at all levels, including exploring potential school-based interventions, Wildsoet says.

In Taiwan, the myopia prevalence among 7-year-olds increased from 5.8 percent in 1983 to 21 percent in 2000. And in South Korea, a large, representative study of 19-year-olds showed that more than 96 percent were myopic in 2010. “So you can pretty much say everybody’s myopic” there, Wildsoet says.

That’s a problem because myopia – characterized by eyeballs that are more egg-shaped than spherical – is linked with a higher risk for various eye diseases such as retinal detachment, glaucoma and cataracts.

What’s more, Wildsoet says, the epidemic poses a public health problem. “Not only the cost of correction, but the cost of actually managing these diseases associated with myopia has huge consequences as the myopia prevalence goes up,” she says.

Fortunately, myopia is not entirely genetic, and therefore, not fate, says Liu, an assistant professor of clinical optometry and vision science at Berkeley. “I have so many parents [with bad eyesight] coming to the clinic saying, ‘No matter what we do, my kids are doomed,’” she says. “This is a very wrong message.”

The right message is that “numerous genetic studies” have shown that the 20-plus genes associated with nearsightedness explain only about 15 percent of the condition’s prevalence, Liu says. That means “it matters how they use their eyes – it’s not preprogrammed,” she says.

Here’s how to use your eyes right:

Get Outside

Australia is one country that’s traditionally lagged behind in myopia progression trends. That’s likely due in part to the down-under lifestyle and landscape that promotes time outdoors, says Wildsoet, who’s Australian.

On the opposite end of the spectrum are some Asian countries, where after school work – not play – is the norm, says Liu, who was born and trained as an optometrist in China. “Not only do they start doing near work at a much earlier age, the total duration of the near work at a very early age is very, very astonishing,” she says.

Those of us stateside can take a cue: Research has linked more time outdoors with decreased risk of myopia progression, even when controlling for the amount of time indoors and reading, Liu says. “If we can encourage kids to stay outdoors as much as they can, that itself serves as a very good protective mechanism for faster progression.”

Take Breaks

Jacquot calls it the “20-20-20” rule: Every 20 minutes of close-up activity – be it reading a book, working on a laptop or texting on a cellphone – look at something about 20 feet away for about 20 seconds. “It can give your eyes a little bit of a break; it of course gives your mind a bit of a break, too,” he says.

That strategy is well-founded. Animal studies, for instance, show that “the total impact to the overall myopic development is very, very different” for long stretches of near focus compared with that same amount of time broken into smaller stints, Liu says.

Taking breaks can also help prevent against computer-aggravated discomforts, including eye strain and fatigue, blurry vision, dry eye and watery eye – “all part of something we’ve come to call ‘computer vision syndrome,’” Jacquot says.

Practice Good "Visual Hygiene"

In the past, vision experts expected vision to stop getting worse by the time patients reached adulthood. “That doesn’t happen anymore,” Jacquot says. “We all have these close-up demands that mean nearsightedness is progressing in our 20s, 30s and even 40s – which used to be the time the eyes started to come back the other direction.”

That’s one of the reasons it’s important to continue to get an annual eye exam – even if you have 20/20 vision now, Jacquot says. That’s different from a vision screening, which only flags major vision problems and can miss eye health conditions, he says.

It’s also important to practice other “visual hygiene” techniques such as making sure your computer monitor is just below eye-level and eating a diet full of leafy greens, fatty fish like salmon, yellow and orange vegetables, and even some dark chocolate and wine, Jacquot says.