This statement summarizes the U.S. Preventive Services Task Force (USPSTF) recommendations on screening for visual impairment in children younger than age 5 years and the supporting scientific evidence, and updates the 1996 recommendations contained in the Guide to Clinical Preventive Services, second edition.¹ In 1996, the USPSTF recommended vision screening for amblyopia and strabismus for all children once before entering school (B recommendation).¹ Since then, the USPSTF criteria to rate the strength of the evidence have changed.² Therefore, this recommendation statement has been updated and revised based on the current USPSTF methodol

In updating its recommendations for children, the USPSTF limited its review to the most common causes of visual impairment: amblyopia (including amblyogenic risk factors) and refractive error not associated with amblyopia.

• The most common causes of visual impairment in children are: (1) amblyopia and its risk factors and (2) refractive error not associated with amblyopia. Amblyopia refers to reduced visual acuity without a detectable organic lesion of the eye and is usually associated with amblyogenic risk factors that interfere with normal binocular vision, such as strabismus (ocular misalignment), anisometropia (a large difference in refractive power between the 2 eyes), cataract (lens opacity), and ptosis (eyelid drooping). Refractive error not associated with amblyopia principally includes myopia (nearsightedness) and hyperopia (farsightedness); both remain correctable regardless of the age at detection.
• Various tests are used widely in the United States to identify visual defects in children, and the choice of tests is influenced by the child's age. During the first year of life, strabismus can be assessed by the cover test and the Hirschberg light reflex test. Screening children younger than age 3 years for visual acuity is more challenging than screening older children and typically requires testing by specially trained personnel. Newer automated techniques can be used to test these children. Photoscreening can detect amblyogenic risk factors such as strabismus, significant refractive error, and media opacities; however, photoscreening cannot detect amblyopia.
• Traditional vision testing requires a cooperative, verbal child and cannot be performed reliably until ages 3 to 4 years. In children older than age 3 years, stereopsis (the ability of both eyes to function together) can be assessed with the Random Dot E test or Titmus Fly Stereotest; visual acuity can be assessed by tests such as the HOTV chart, Lea symbols, or the tumbling E. Some of these tests have better test characteristics than others.
• Based on their review of current evidence, the USPSTF was unable to determine the optimal screening tests, periodicity of screening, or technical proficiency required of the screening clinician. Based on expert opinion, the American Academy of Pediatrics (AAP) recommends the following vision screening be performed at all well-child visits for children starting in the newborn period to 3 years: ocular history, vision assessment, external inspection of the eyes and lids, ocular motility assessment, pupil examination, and red reflex examination. For children aged 3 to 5 years, the AAP recommends the aforementioned screening in addition to age-appropriate visual acuity measurement (using HOTV or tumbling E tests) and ophthalmoscopy.³
• The USPSTF found that early detection and treatment of amblyopia and amblyogenic risk factors can improve visual acuity. These treatments include surgery for strabismus and cataracts; use of glasses, contact lenses, or refractive surgery treatments to correct refractive error; and visual training, patching, or atropine therapy of the nonamblyopic eye to treat amblyopia.
• These recommendations do not address screening for other anatomic or pathologic entities, such as macro cornea, cataracts, retinal abnormalities, or neonatal neuroblastoma, nor do they address newer screening technologies currently under investigation.

Visual impairment caused by refractive error, amblyopia, strabismus, and astigmatism is a common condition among young children, affecting 5 percent to 10 percent of all preschoolers. Amblyopia is present in 1 percent to 4 percent of preschool children; an estimated 5 percent to 7 percent of preschool children have refractive errors.² Uncorrected amblyopia may harm school performance, ability to learn, and later, adult self-image.⁴ Furthermore, uncorrected amblyopia may be a risk factor for future total blindness. Because visual impairment in children is common and believed to have an early sensitive period when interventions lead to better outcomes, much interest has focused on primary care vision-screening tools for early detection, referral, and treatment.

The USPSTF found no direct evidence that screening for visual impairment, compared with no screening, leads to improved visual acuity. However, the USPSTF found 1 fair quality study showing that intense screening by eye professionals (compared with usual screening) decreases the prevalence of amblyopia.⁵ This recent randomized controlled trial in the United Kingdom, the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC) trial,⁵ has reported that intensive screening performed 6 times between ages 8 and 37 months (using the cover test, Cardiff Cards, Kay Picture test, and HOTV letters by an eye professional) led to decreased prevalence of amblyopia and improved visual acuity compared with a 1-time visual screening at age 37 months (using Kays Picture test and HOTV letters). Any child failing a screening test was referred to the hospital eye service for further testing and treatment. Compared with the group screened once at age 37 months, the intensively-screened group had a significantly lower prevalence of severe amblyopia at age 7.5 years (amblyopia B prevalence = 0.6 percent vs 1.8 percent) and a lower prevalence of residual amblyopia after treatment (7.5 percent vs 25 percent).

The USPSTF reviewed the evidence for the accuracy of vision screening tests in children younger than age 5 years. The USPSTF found no evidence evaluating the role of screening for family history or parental concern, or evaluating the accuracy of the clinical examination to detect visual impairments such as cataracts or strabismus. One fair quality study of children aged 3 to 5 years screened by public health nurses with annual tests, including Cambridge Crowding Cards, the Hirschberg test, and the Titmus Fly Stereotest, reported an overall sensitivity of 60 percent to 71 percent and a specificity of 70 percent to 80 percent.⁶ A good quality systematic review, evaluating the accuracy of the Snellen E test or Stycar graded balls and the Titmus Fly Stereotest in children aged 3 to 5 years, reported an estimated sensitivity of 9 percent to 12.5 percent and a specificity of 99 percent.⁷ Three poor quality studies examined the accuracy of the Medical Technology Incorporated (MTI) photoscreener™ in a population of children younger than age 3 years with a high prevalence of visual impairment. Sensitivity ranged from 37 percent to 88 percent, and specificity ranged from 40 percent to 88 percent.^8-10 For the Visiscreen™ in children younger than age 3 years, overall sensitivity and specificity were 85 percent and 94 percent, respectively.¹¹

The USPSTF found fair quality evidence that early treatment of amblyogenic risk factors, including strabismus, refractive error, and cataracts, prevents amblyopia.^12-15 Indirect evidence for the effectiveness of amblyopia treatment comes from cross-sectional studies that show lower prevalence of visual impairment in screened populations compared with unscreened populations.^16,17 Cohort studies show that among children who have been diagnosed with visual impairment, amblyopia is unlikely to improve without therapy.¹⁸ Both prospective and retrospective studies report that between approximately 40 percent and 95 percent of persons with amblyopia have improved visual acuity after treatment.^19-31 Two fair quality studies of treatment for amblyopia have found that successful outcomes depend on earlier treatment.^22,29 In these studies, treatment efficacy steadily decreased after age 3 years; by age 12 years, treatment was ineffective. However, there is fair evidence to suggest that a modest delay in treatment does not harm outcomes.³² Since the USPSTF found no studies that followed patients into adulthood, the long-term effectiveness of the interventions for amblyopia is unclear.

The USPSTF found no studies detailing permanent harms resulting from screening or data regarding the harms of false-positive screening. However, potential harms of screening may include "labeling" and the costs associated with the further evaluation of children with false-positive screening results. Potential harms of interventions include disruption of normal eye development and temporary loss of visual acuity of the nonamblyopic eye, which resolves weeks after completion of therapy.³³

There is limited research regarding the performance of vision screening tests in the primary care setting, although there are studies currently underway comparing various screening methods.^34-36 Current studies reviewed by the USPSTF, including the ALSPAC study,⁵ support the effectiveness of intensive screening; however, it is not clear whether the magnitude of benefit observed in the United Kingdom study is generalizable to the United States population, to children younger than age 3 years, or to services provided by primary care clinicians. It would be helpful if similar studies comparing early, intensive screening to usual visual screening were performed in children younger than age 5 years using screening tests commonly performed in the United States by primary care clinicians.

The recommendation of the American Academy of Family Physicians can be accessed at www.aafp.org/x7661.xml.

The joint recommendation of the American Academy of Pediatrics, American Association for Pediatric Ophthalmology and Strabismus, and the American Academy of Ophthalmology, can be accessed at aappolicy.aappublications.org.

The clinical practice guideline of the American Optometric Association can be accessed at www.aoa.org/documents/CPG-2.pdf.

The recommendation of the Canadian Task Force on the Periodic Health Examination can be accessed at www.ctfphc.org/Full_Text/Ch27full.htm.

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Members of the U.S. Preventive Services Task Force* are Alfred O. Berg, M.D., M.P.H., Chair, USPSTF (Professor and Chair, Department of Family Medicine, University of Washington, Seattle, WA); Janet D. Allan, Ph.D., R.N., C.S., Vice-chair, USPSTF (Dean, School of Nursing, University of Maryland Baltimore, Baltimore, MD); Ned Calonge, M.D., M.P.H. (Acting Chief Medical Officer, Colorado Department of Public Health and Environment, Denver, CO); Paul Frame, M.D. (Tri-County Family Medicine, Cohocton, NY, and Clinical Professor of Family Medicine, University of Rochester, Rochester, NY); Joxel Garcia, M.D., M.B.A. (Deputy Director, Pan American Health Organization, Washington, DC); Russell Harris, M.D., M.P.H. (Associate Professor of Medicine, Sheps Center for Health Services Research, University of North Carolina School of Medicine, Chapel Hill, NC); Mark S. Johnson, M.D., M.P.H. (Professor of Family Medicine, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, NJ); Jonathan D. Klein, M.D., M.P.H. (Associate Professor, Department of Pediatrics, University of Rochester School of Medicine, Rochester, NY); Carol Loveland-Cherry, Ph.D., R.N. (Executive Associate Dean, School of Nursing, University of Michigan, Ann Arbor, MI); Virginia A. Moyer, M.D., M.P.H. (Professor, Department of Pediatrics, University of Texas at Houston, Houston, TX); C. Tracy Orleans, Ph.D. (Senior Scientist, The Robert Wood Johnson Foundation, Princeton, NJ); Albert L. Siu, M.D., M.S.P.H. (Professor and Chairman, Brookdale Department of Geriatrics and Adult Development, Mount Sinai Medical Center, New York, NY); Steven M. Teutsch, M.D., M.P.H. (Executive Director, Outcomes Research and Management, Merck & Company, Inc., West Point, PA); Carolyn Westhoff, M.D., M.Sc. (Professor of Obstetrics and Gynecology and Professor of Public Health, Columbia University, New York, NY); and Steven H. Woolf, M.D., M.P.H. (Professor, Department of Family Practice and Department of Preventive and Community Medicine and Director of Research, Department of Family Practice, Virginia Commonwealth University, Fairfax, VA).

* Member of the USPSTF at the time this recommendation was finalized. For a list of current Task Force members, go to https://www.uspreventiveservicestaskforce.org/Page/Name/about-us.

Source: This recommendation first appeared in Ann Fam Med 2004;2:263-6.

This document is in the public domain within the United States. Requests for linking or to incorporate content in electronic resources should be sent via the USPSTF contact form.