The classroom blackboard is frequently the unofficial litmus test in recognizing kids' vision problems. They might move closer to the board to see, or tilt their heads slightly while seated at their desks to bring words or numbers into view.

And in today's classroom, many students are growing accustomed to white boards, which Dr. Mrunalini Parvataneni, a pediatric ophthalmologist at Northwest Eye in Maple Grove and Wayzata, said can be even tougher for some kids with vision problems.

"The glare that comes off the white board can make it hard for kids to see what's written," she said. "I have been hearing more complaints from kids about that.

"It's another story with smart boards. Those are often easier for kids to see, due to the higher resolution screen; the teacher can also make the print larger or smaller."

Asked if the prevalence in screen time for kids is leading to more eye problems in general, Parvataneni said there has been an increase in reported vision fatigue among kids and adults who spend hours in front of computers.

"We do not know enough about the long-term effects of constant screen time, but that is why I counsel my families to just be cautious," she said, adding that due to the inherent ability kids have to focus their eyes, smaller screens such as those found on smartphones don't necessarily cause further strain.

Pay attention to headaches

Parents also should pay attention to a child's complaints about headaches and/or eye fatigue -- and when they mention it.

"If it's an eye problem, it will occur across the board," Parvataneni said. "If they only mention it while they are working on a subject they don't like, that is a different situation."

A lazy eye, which she said typically becomes apparent before the child enters school, can also present as late as age 7 or 8. If a child's eye wanders toward the nose, this will be more evident to parents as they spot their child bringing books or other materials closer to their eyes to see.

"Teachers are often the ones to first notice a child with a lazy eye that turns outwards towards the ear, because that is easier to observe from a distance," she said.

If the child is having trouble with eye alignment, known as strabismus, head-tilting may become more common, although Parvataneni said many kids with strabismus become so accustomed to tilting their heads to see something at a distance that they might not even realize they are doing it.

She said she always advises parents first to visit the child's primary-care physician with any eye or vision concerns to make sure the doctor is "in the loop" regarding any potential problems.

Regular vision screening also is paramount, she added. The Minnesota Vision Screening Guidelines, recommended by the Minnesota Department of Health, recommend that all children participate in early childhood screening for visual acuity by age 6; vision screening is also recommended for children in grades one, three, five, seven and 10.

For kids in elementary school and beyond, another potential threat to healthy vision occurs during contact sports such as hockey, football and basketball. According to the American Association for Pediatric Ophthalmology and Strabismus, close to 50 percent of eye injuries happen during sports and recreational activities and occur in kids and teens more frequently than in any other age group.

Eye protection urged for all sports

"My opinion is that kids should have eye protection for every sport," Parvataneni said. "And if I have a patient with poor vision in one eye, as a parent, I would think twice about putting kids in contact sports."

For kids in contact sports who are wearing protective eye gear, the subject of contact lenses frequently comes up when they are around 9 or 10, often an age when they also may consider glasses a nuisance.

"Kids need to be responsible enough to take on contacts, and that does typically happen around this age," she said. "Most kids are pretty happy with glasses until they are about 10 or 11. After that, the image factor starts to make a difference. They want to look a different way."

Julie Pfitzinger is a West St. Paul freelance writer.