Summary of Recommendations and Evidence

The U.S. Preventive Services Task Force (USPSTF) recommends vision screening for all children at least once between the ages of three and five years to detect the presence of amblyopia or its risk factors (Table 1). B recommendation.

The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of vision screening for children younger than three years. I statement.

Rationale

Importance. Approximately 2 to 4 percent of preschool-aged children have amblyopia, an alteration in the visual neural pathway in the developing brain that can lead to permanent vision loss in the affected eye. Amblyopia usually occurs unilaterally, but can occur bilaterally. Identification of vision impairment before school entry could help identify children who may benefit from early interventions to correct or improve vision.

Detection. The USPSTF found adequate evidence that vision screening tools have reasonable accuracy in detecting visual impairment, including refractive errors, strabismus, and amblyopia.

Benefits of detection and early intervention. The USPSTF found adequate evidence that early treatment for amblyopia, including the use of cycloplegic agents, patching, and eyeglasses, for children three to five years of age leads to improved vision outcomes. The USPSTF found inadequate evidence that early treatment of amblyopia for children younger than three years leads to improved vision outcomes.

Harms of detection and early intervention. The USPSTF found limited evidence regarding harms of screening, including psychosocial adverse effects, for children three years and older. False-positive screening results may lead to the overprescribing of corrective lenses. Adequate evidence suggests that the harms of treatment of amblyopia for children three years and older are limited to reversible loss of visual acuity resulting from patching of the nonaffected eye. The USPSTF found inadequate evidence of the harms of screening and treatment for children younger than three years.

USPSTF assessment. The USPST-F concludes with moderate certainty that vision screening for children three to five years of age has a moderate net benefit. The USPSTF concludes that the benefits of vision screening for children younger than three years are uncertain and that the balance of benefits and harms cannot be determined for this age group.

Clinical Considerations

Patient population. This recommendation applies to all children one to five years of age.

Screening tests. Various screening tests that are feasible in primary care are used to identify visual impairment among children. These tests include visual acuity tests, stereo-acuity tests, the cover-uncover test, and the Hirschberg light reflex test (for ocular alignment/strabismus), as well as the use of autorefractors (automated optical instruments that detect refractive errors) and photoscreeners (instruments that detect amblyogenic risk factors and refractive errors).

Treatment. Primary treatment for amblyopia includes the use of corrective lenses, patching, or atropine treatment of the nonaffected eye. Treatment may consist of a combination of interventions.

Suggestions for practice regarding

I statement. In deciding whether to refer children younger than three years for screening, clinicians should consider the following:

• Potential preventable burden. Most studies show that screening and treatment later in the preschool years seem to be as effective at preventing amblyopia as screening and treatment earlier in life.

• Costs. Potential disadvantages of using photoscreeners and autorefractors are the initial high costs associated with the instruments and the need for external interpretation of screening results with some photoscreeners.

• Current practice. Typical components of vision screening include assessments of visual acuity, strabismus, and stereoacuity. Younger children often are unable to cooperate with some of the screening tests performed in clinical practice, such as visual acuity testing. Stereoacuity testing often is omitted and may be performed incorrectly when attempted. Screening of younger children may be difficult and often yields false-positive results because of the child's inability to cooperate with testing. Children with positive findings should be referred for a full ophthalmologic examination to confirm the presence of vision problems and to receive further treatment.

Screening intervals. The USPSTF did not find adequate evidence to determine the optimal screening interval.