When the zombies come, Marissa DeJesus fears she won’t be able to see well enough to escape the marauding horde. “I have terrible vision. If something happens in the middle of the night, God forbid, I probably couldn’t find anything. It would be a significant hardship if we have a zombie apocalypse.”

An even more pressing fear: that eventually her 3 daughters, who also are nearsighted, will have vision as bad as her own.

But a new study offers hope that a type of contact lenses usually worn by older people could slow or even stop the progression of nearsightedness – also known as myopia -- when prescribed for adolescents.

The study, published in the Journal of the American Medical Association , found that treatment with high add power multifocal contact lenses significantly reduced the rate of myopia progression.

Like Bifocals in a Contact Lens

Add power lenses are contact lenses that provide stronger power for up-close activities, like reading. They also help the wearer see far away, explained optometrist Jeffrey Walline, OD, PhD, Associate Dean for Research at The Ohio State University College of Optometry, and the study’s lead author. “They’re like bifocals in contact lens form,” Dr. Walline said in an interview with Medical Daily. The lenses come in 3 levels of added power.

Where regular glasses and contact lenses for nearsightedness focus light directly on the retina, lenses that help people see up close focus light in front of the retina. The power added lenses do both, Dr. Walline explained. “We believe what slows the progression of nearsightedness is the light focusing in front of the retina. We believe that slows eye growth,” he said.

The double-blind study followed 294 children aged 7 to 11 – including two of Ms. DeJesus’ daughters – for 3 years. The researchers documented changes in eyesight and compared the effect of regular lenses, medium add power and high add power lenses.

One of Most Common Vision Impairments Under Age 40

Myopia is one of the most common causes of vision impairment in people under age 40. In one study, nearly 42% of children between ages 5 and 19 were nearsighted. Myopia occurs when the eyeball grows too long, Dr. Walline said. And that growth typically occurs in childhood or adolescence, which is when nearsightedness often first appears. When the condition develops in childhood, it is likely to worsen over time.

Ms. DeJesus said her youngest and oldest daughters were in glasses by kindergarten; the middle daughter made it to second grade before her vision needed correcting.

“My husband’s eyesight is bad too. I feel like we cursed the poor kids,” she said.

As common as it already is, research indicates myopia is becoming even more widespread. A 2016 study published in the journal Ophthalmology predicted that, based on current trends, almost half the world’s population – some 4,758 million people – will be nearsighted by 2050.

The most widely accepted hypothesis to explain the increase is that kids are spending less time outside in natural light, said Walline. The Ophthalmology study presented the same theory.

Contact Lenses Increasingly Popular Among Children

A decade ago, it was unusual for kids as young as those in the study to wear contact lenses, Dr. Walline said. But the advent of daily disposable lenses, which are more comfortable and easier to care for, has propelled a shift toward more middle-school and even grade-school-age kids wearing contacts.

Ms. DeJesus said her main concerns about having her young daughters trade their glasses for contact lenses was the hygiene aspect, and whether they would be able to put the lenses in and take them out. “If they couldn’t handle that on their own, that would be a deal-breaker.”

In preventing nearsightedness from getting worse, there is more at stake than merely avoiding the cost of continually buying new, stronger glasses or contact lenses, Dr. Walline said. Those with extreme myopia face greater risk for detached retinas, cataracts, and glaucoma, he explained.

Not to mention a greater disadvantage during a zombie apocalypse. Ms. DeJesus said her myopia is so severe that she sees 3 eye doctors each year – including a retinal specialist. “My retina is so thinned out that there is significant risk for detachment,” she said.

Retinal detachment separates the retinal cells from blood vessels that provide oxygen and nourishment. If untreated, it can result in permanent vision loss in the affected eye. “Hopefully, my kids can be spared all that,” she said.

That’s one reason Ms. DeJesus said she was thrilled to have 2 daughters participate in the study – the third was older than the study parameters permitted. And both are now participating in a second phase of the study, which is looking at whether the slowed progression of myopia can be sustained.