It’s not exactly like your 2-year-old is going to tell you that the page of the chapter book he’s reading looks blurry. So if you think his vision is less than stellar, you’re going to have to rely on some visual cues instead.

One of the main signs that toddlers or preschoolers exhibit when they’re having trouble with their vision is sitting too close to the television. If your kid keeps running up to the television to watch his favorite show, he may have a vision issue.

Another telltale sign, says Dr. Mel Friedman, optometrist and eye specialist in Memphis, Tenn., is if your toddler or preschooler is abnormally close to the paper he's coloring (or scribbling) on.

child very close to tvOf course, squinting is another symptom that there may be a problem. “Chances are though, if you’re noticing squinting, then there may be a refractive issue,” Friedman tells MNN. If your child is squinting, he may be farsighted, nearsighted, or have astigmatism (when the cornea is shaped liked a football instead of a basketball), thus causing blurred vision. Squinting helps rectify that by limiting the rays of light that come in through the top and the bottom on the lens, allowing the light to come closer to the center of the lens, thereby creating a more focused image. If your child is squinting, become suspicious and investigate the issue.

Friedman also suggests playing vision games with your child often. When you’re in the car, ask if he sees things that you see; to find the fire truck or tree outside and then let him tell you what color those objects are. You can also play “I Spy” with (“I spy something red”) to see if he can spot different colors. As kids get older, ask them to identify letters or numbers on signs or license plates. “By making your child astutely aware of his or her environment,” explains Friedman, “you are giving them the advantage of knowing when something doesn’t look right.” You can also have them cover one eye at a time and see if things are clearer out of one eye as opposed to the other eye. (This tactic works better with 3- or 4-year-olds better than 1- or 2-year-olds.)

Kids can start getting yearly eye exams by the time they’re 3 or 4 years old. A lot of parents bring kids in for an eye exam just before school starts, but this is a mistake, says Friedman. It’s better to do the eye exam two weeks after school has started, when the visual demands have begun and visual problems are more apparent.

Some pediatricians will do a preliminary vision screening at your child’s yearly physical. My pediatrician started using PediaVision’s Spot Vision machine, which essentially takes a picture of your child’s eyes. Usually a good gauge of whether your child needs further screening (and not necessarily a diagnosis unto itself), this type of screening is helping to diagnose and treat vision problems even in very young children.

Yearly vision exams will help diagnose a problem known as amblyopia. One type of amblyopia occurs when a child is born with an undeveloped retina, leading to permanent visual loss. Another kind is refractive amblopia, when a child has a significant refractive error in one eye and does not in the other. The child will begin to rely on the better eye, causing the other eye to “drift off.” An experienced eye doctor can often spot the issue in children as young as 6 months. Early treatment of amblyopia can prevent problems down the road. As a parent, if you begin to see symptoms of these issues, such as one eye wandering inward or outward, take your child to see a pediatric optometrist or ophthalmologist.

If your child does end up needing glasses, it may seem daunting to keep them on him. But if they’re improving his vision, it’ll probably be easier than you think, since keeping them on means a clearer, more vivid world for him to see.

— Chanie

You can submit a question to Mother Nature, and one of our many experts will track down the answer. Plus: Visit our advice archives to see if your question has already been tackled.

Related children's health stories on MNN: