Eye Health Report: Kids' vision check

Do you know how to spot a lazy eye? The signs aren’t always obvious. Learn about this condition and the ways to treat it. (Hint: It involves video games!)

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Health Health Report in partnership with Doctors of Optometry Canada

Rochelle Hannon will never forget the shock she felt when she was told by a vision specialist that her then-four-year-old daughter, Jocelyn, was legally blind in her left eye. The Abbotsford, BC, mom of four immediately panicked about whether Jocelyn would be able to play sports, or drive when she got older. “I started bawling. I was so upset. How could we not know? But we had no indication anything was wrong—her eyes weren’t crooked, she didn’t sit close to the TV and she was learning to read before she hit kindergarten. If I’d known you can get kids’ eyes tested as young as six months, I would have taken her a lot earlier.”

“Research suggests that one in four school-aged kids has a vision problem,” says Gurpreet Leekha, a doctor of optometry in Victoria, and the referral rate from school screening programs is only about one in eight, which means at least 50 percent of kids who need help are being missed. Good vision is key for educational success; in fact, 60 percent of learning disabilities are thought to stem from undiagnosed eye problems. What’s more, unlike an exam by a doctor of optometry, who’s trained to diagnose and treat vision problems, vision screenings don’t include tests to assess eye health.

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Jocelyn was lucky, though; her poor eyesight hadn’t interfered with learning yet. Being legally blind meant that she had less than 20/200 vision in her “weaker” eye—she would have to be less than 20 feet away to see what someone with normal vision could see at 200 feet­­—but could still see close up. Due to a problem called amblyopia, which affects up to five percent of kids, she was essentially seeing with only one eye, leaving her without three-dimensional vision. Commonly known as “lazy eye,” the condition actually has as much to do with the brain as the eye: Because the brain can’t merge both of the images it receives from the eyes into a single clear 3-D picture, it starts ignoring input from the weaker eye. “In the early years of life, the brain learns how to use the eyes,” says Joe Chan, a doctor of optometry in Mississauga, Ont. So unless the problem is detected and dealt with by around age seven, it often becomes permanent. And generally, the earlier amblyopia is detected, the more quickly it responds to treatment.

Jocelyn developed amblyopia because her eyes were extremely mismatched: Think of it as having two very different lens prescriptions. But in other kids, like Brenda Kovitz’s seven-and-a-half-year-old twins, Sasha and Ben, part of the problem stems from an imbalance in the muscles that help focus the eyes. While this sometimes causes one eye to wander noticeably, often it isn’t visible, as Kovitz can attest. The Victoria mom, who runs a drop-in play centre, had no inkling her kids, then three and a half years old, had the serious vision problem before a chance encounter with another mom prompted her to take them for an eye exam. “There was a girl at the daycare one day with a patch on her eye, so I asked the parent about it,” she says. After the mom explained that her daughter had a lazy eye, Kovitz­—worried that her kids had never had their eyes checked—immediately began looking for a doctor of optometry.

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Not long afterward, Sasha and Ben were sporting eye patches, too. Amblyopia is treated by strengthening the connection between the brain and the “bad” eye. In mild cases, this can sometimes be done by correcting the poor eye’s focusing ability with glasses. Otherwise, we have to teach the brain to accept equal input from both eyes, Leekha explains. This is done by patching the good eye (anywhere from one to 12 waking hours a day, depending on the severity of the problem), which forces the weaker one to take over. With time, the brain learns how to use the eyes properly. While Jocelyn had to be patched on and off from ages four to nine, for some kids, like Sasha, it only takes a few months to notice signs of improvement. “We bought three or four different styles to see which ones the kids felt the most comfortable in,” says Kovitz. (Adhesive bandage-like stickers are the most common type.) “They come in different patterns, so kids can help pick them out. I think the younger the child is, the easier it is to get her to keep it on.” Age-appropriate explanations of why wearing the patch is important, and distractions like favourite activities, can help kids resist the urge to remove it.

Some kids, like Ben, need extra help to retrain their brains and strengthen and train their eye muscles to work together, either by doing vision exercises or playing video games with the better eye patched. Not only are video games a great motivator (kids don’t mind the patch if they get to play while they wear it!), “there is growing evidence that they reduce the time required to restore vision in the weak eye by 20 to 30 percent,” says Leekha, who estimates that roughly a third of doctors of optometry now prescribe video games as part of amblyopia therapy. High-speed 3-D graphics seem to help the brain and eyes learn to work together more quickly. The best options are games with an element of depth perception (where objects increase and decrease in size as they get closer and further away) that also incorporate lots of movement, colour and visual stimulation. Kid-approved examples include car-racing games like “Mario Kart” and coordinative exercise apps like “Captain Lazy Eye,” which train the eyes to work as a team.

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Although Hannon wishes she’d known about her daughter’s eyes sooner, Jocelyn, now 10, has 20/20 vision with her glasses, and she’s not only an A student, but a crackerjack lacrosse player whose team made it to the BC provincial championships. Sasha and Ben, now seven, are both doing well in school, too. While Ben still has ongoing eye issues, “they’re probably not nearly as severe as they would have been if we’d waited until one of his teachers noticed something was wrong,” says Kovitz. “I have a friend whose son is going into grade three, and he can’t read—she’s worried about him. I said, ‘You need to get his eyes checked.’ It turns out that, like Sasha, he has a lazy eye that doesn’t wander.”

Eye of exam fact — Kids don’t need to know the alphabet, or to have spoken their first words, to have their eyes examined: “We suggest an initial visit between six and nine months,” explains Joe Chan, a doctor of optometry from Mississauga, Ont. “Obviously, at that age, we don’t get much feedback from the baby, but we do get a lot of important information.” For instance, by looking into the baby’s eyes with a light instrument called an ophthalmoscope, the doctor can assess the health of structures like the retina and lens. “We can also measure things like eye coordination and function,” Chan says. “We check the pupils to make sure they’re working properly. We even have instruments that can estimate what the prescription of the eye is, so we can determine whether the child is at risk for far-sightedness or nearsightedness or astigmatism.” All of this can be done in three or four minutes, while the baby is sitting comfortably in her parent’s lap. For preschoolers, “we can get a pretty good sense of what the child’s vision is like using symbol charts,” Chan adds. (Once kids get to school, exams resemble the ones adults undergo.) Usually, drops to dilate the pupils are used when vision problems like amblyopia or far-sightedness are suspected.

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A version of this story appeared in our October 2014 issue with the headline Eye Health Report: Kids’ vision check.

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