Aug. 3 (HealthDay News) -- More than 20 percent of kids aged 12 to 17 have trouble seeing the classroom chalkboard, a new national survey shows.

Of the nearly 1,500 children in the survey, more than 25 percent of the teen age group complained of headaches, even though 45 percent of them wore some type of prescription eyewear.

About 25 percent of children aged 6 to 11 wear prescription glasses, according to the survey, conducted by Prevent Blindness America and VSP Vision Care. Eye problems among children increase with age.

The most common vision problem in older children was nearsightedness (myopia), a condition in which close objects are seen clearly but objects that are far away, such as chalkboards, are blurry.

All children should have their vision checked regularly, according to Prevent Blindness America. Unfortunately, more than 66 percent of those under the age of 6 have never had their eyes examined by an eye doctor, the survey found.

"The good news is that most common eye problems in older children, including myopia, can be effectively treated if diagnosed early. We urge all parents and caregivers to have their child's vision checked regularly to promote a lifetime of healthy vision," Hugh R. Parry, president and CEO of Prevent Blindness America, said in a news release from the organization.

SOURCE: Prevent Blindness America/VSP Vision Care, news release, Aug. 3, 2009