Pre-School Eye Screenings: Are They Enough?

The issue of comprehensive eye exams for children hasn't received much attention until recently. This O.D. points out why it's important.

The issue of comprehensive eye exams for children hasn't received much attention until recently. This O.D. points out why it's important.
BY CARL F. GRUNING, O.D., F.C.O.V.D., F.A.A.O. Fairfield, Conn.

In this new millennium, there's a new emerging drive -- one that's close to my professional heart -- mandatory, pre-school eye and vision examinations.

Vision disorders are the leading cause of handicapping conditions in children. In fact, according to a recent Prevent Blindness America press release, sources estimate that vision problems in nearly 430,000 children can cause permanent loss of sight if left untreated.

According to the American Academy of Pediatrics, undetected vision problems are common in preschool children, with an estimated prevalence of 5% to 10%.

excessive farsightedness   


(near blur/eyestrain)



(near/far blur)



(distance blur)

binocular disorders   


(reduced efficiency/discomfort)



(poor depth, cosmesis)




focus disorders   



Prevent Blindness America recommends that parents take their children to see an eyecare practitioner for a complete eye examination shortly after birth, again at 6 months and between the ages of 3 and 5. However, only 14% of preschool children receive a comprehensive vision examination before entering the first grade.

Many to follow

Kentucky was the first state to mandate such a law and now other states (e.g., Connecticut, California, Missouri and Massachusetts) are following suit. Why is there a need for mandatory pre-school eye and vision exams? In late March of this year, the Connecticut Association of Optometrists asked me to provide documentation on the drawbacks of Snellen chart screening and explain why mandatory exams are necessary. The following is a summary of what I found in my search of the literature:

  • In a sample of about a 100 pediatric practices across the nation, vision screenings were attempted on only 38% of 3 year olds, and only 26% who failed the American Academy of Pediatrics vision screening guidelines were referred for professional exams.
  • Of children under 6 years of age, only 14% have had an eye or vision exam. This fact is largely derived from the myth that the current pediatric and school screenings are sufficient and complete.
  • Only 30% of school-age children have had an eye exam within the past year, in spite of the high prevalence of vision disorders in this population.
  • The interrelationship between vision problems and learning difficulties and the cost of undetected vision problems to society are of major concern.
  • Vision problems may not be the direct cause of learning disorders, but they can interfere with a child's ability to perform to his potential. When a child fails to progress in school, the cost to society is enormous, especially in the way of special education services.

Trends in pediatric vision disorders

A major study conducted in 1965 by the Department of Health, Education and Welfare on more than 7,000 young children found that almost 10% of them had either a muscle imbalance, an ocular disease or other abnormality in one or both of their eyes.

Other disorders in the pediatric population show a prevalence of the following magnitude:

Six million Americans have a vision deficit caused by amblyopia. Each year, 75,000 new cases of amblyopia are found each year in 3 year olds. Amblyopia is responsible for vision loss in more people under 45 years of age than all other forms of ocular disease and trauma.

N.C. task force report

Since 1987, North Carolina has required children to undergo vision screening before entering school. But in 1995, a state health department task force declared that although the "vision screening requirement is sound, it has weaknesses that significantly impair its effectiveness."

Screenings don't detect many important vision problems. They only detect visual acuity problems, and more importantly, they give parents a false sense of security. An eye vision examination between 3 and 4 years of age is, and has always been, the most effective approach to the prevention and early detection of eye and vision problems in pre-school children.

The task force was comprised of representatives from the State Academy of Ophthalmology, the Society to Prevent Blindness, the Optometric Society, the Pediatric Society, the Nurses Association and the Academy of Family Physicians.

According to task force member David Anderson, O.D., who represents the North Carolina State Optometric Society, the task force's "most significant statement" was unanimously supporting the concept that the best alternative for vision care was a comprehensive eye exam by an eyecare professional (optometrist or ophthalmologist) at age 3 with a primary focus on the detection and treatment of amblyopia.

The task force also concluded in its report that if "a comprehensive exam can't be accomplished at age 3, it should be performed as soon thereafter as possible."

Vision screening weaknesses

It's appalling to consider the frequency of extensive delays in initiating treatment for children who have known impaired vision -- a serious problem that interferes with classroom learning at a critical stage in a child's educational and social development.

When a child fails a screening, it's important that his parents are notified. The parents should then heed the advice they receive about their child's vision. Unfortunately, studies published in the Journal of School Health highlight the problems of significant non-compliance with school screening referral letters.

In evaluating 18,000 children over 4 years, some 2,887 children were found to have vision problems. But 20% who failed didn't receive professional services after the referral, and those who were seen professionally experienced a time lag of almost 2 years. The youngest children suffered the longest delay in treatment. Also, screening programs don't treat vision impairment. At best, they may identify some children with treatable problems, but they don't correct the problem.

These findings are consistent with my own clinical experience. In the Minnesota study, children ages 5 to 6 experienced a mean lag from referral to professional eye care of 3.7 years!

Further drawbacks

In a large study in New York State of 1,983 children, the Snellen chart was found to be highly specific (i.e., 100% who fail do have a problem with distance acuity; but it's insensitive, missing 75% of children who pass just acuity -- that is, high specificity and low sensitivity).

Liana Fresher, president and CEO of Prevent Blindness Connecticut, says, "Unfortunately, the majority of the more than 270,000 Connecticut children age 5 years or younger will not have a vision screening or vision test before school age. Some will suffer irreversible damage to their vision because the discovery of their vision problems will come too late."

Even President George W. Bush was quoted in the April 1st edition of The Boston Globe's editorial page as saying, "No child in America should be segregated by low expectations . . ., imprisoned by illiteracy . . . abandoned to frustration and the darkness of self-doubt."

Benefits derived

With the passage of the DPA and TPA laws, not only did scope of practice match our optometric education, but we achieved the right to do what we'd been trained to do -- serve our patients better. Similarly, when mandatory pre-school eye and vision exams are enacted, undiagnosed vision disorders ranging from simple focusing problems to learning-related vision problems may cease from contributing to a host of reading, learning and behavior problems among our children. Primary care physicians aren't conducting pediatric vision screenings on a regular basis and are therefore placing our children at risk.

The Kentucky laws found that up to 19% of children need eyeglasses. As in most other states, all children previously required a screening before entering school, but not a comprehensive eye exam by an O.D. or M.D.

Make a stand

If optometry is to best serve the visual needs of America's children, we need to encourage educators, pediatricians and legislators to abandon the current eye screenings that use techniques developed almost 150 years ago.

Comprehensive eye and vision exams performed by an optometrist or an ophthalmologist are greatly needed and more beneficial than simple screenings. If problems arise and the O.D. isn't well versed in pediatrics, then he should make a referral to an optometric colleague who does provide the services.

Dr. Gruning is board certified in vision therapy. He's a professor at SUNY Optometry and past president of the College of Optometrists in Vision Development.