Grade: B The USPSTF recommends the service. There is high certainty that the net benefit is moderate or there is moderate certainty that the net benefit is moderate to substantial.
The USPSTF recommends vision screening at least once in all children aged 3 to 5 years to detect amblyopia or its risk factors.
Frequency of Service
Recommends vision screening at least once in all children aged 3 to 5 years to detect amblyopia or its risk factor.
Risk Factor Information
Risk factors for amblyopia include strabismus; high, uncorrected refractive errors (eg, myopia, hyperopia, and astigmatism); anisometropia; and media opacity.1-3 Additional risk factors associated with amblyopia, strabismus, or refractive errors include family history in a first-degree relative, prematurity, low birth weight, maternal substance abuse, maternal smoking during pregnancy, and low levels of parental education.1, 8-13
Patient Population Under Consideration
This recommendation applies to children aged 6 months to 5 years.
Risk Factors Associated With Amblyopia
Although all children aged 3 to 5 years are at risk of vision abnormalities and should be screened, there are certain risk factors that increase risk. Risk factors for amblyopia include strabismus; high, uncorrected refractive errors (eg, myopia, hyperopia, and astigmatism); anisometropia; and media opacity.1-3 Additional risk factors associated with amblyopia, strabismus, or refractive errors include family history in a first-degree relative, prematurity, low birth weight, maternal substance abuse, maternal smoking during pregnancy, and low levels of parental education.1,8-13
A variety of screening tests are used to identify vision abnormalities in children in primary care settings (Table 2). Visual acuity tests screen for visual deficits associated with amblyopia and refractive error. Ocular alignment tests screen for strabismus. Steroacuity tests assess depth perception.1,14 For children younger than 3 years, screening may include the fixation and follow test (for visual acuity), the red reflex test (for media opacity), and the corneal light reflex test (for strabismus).1,14 Instrument-based vision screening (ie, with autorefractors and photoscreeners) may be used in very young children, including infants. Autorefractors are computerized instruments that detect refractive errors; photoscreeners detect amblyopia risk factors (ocular alignment and media opacity) and refractive errors.1,15 Vision screening in children older than 3 years may include the red reflex test, the cover-uncover test (for strabismus), the corneal light reflex test, visual acuity tests (eg, Snellen, Lea Symbols [Lea-Test], and HOTV [Precision Vision] charts), autorefractors and photoscreeners, and stereoacuity tests.1,14 Children with positive findings should be referred for a complete eye examination to confirm the presence of vision problems and for further treatment.
The USPSTF did not find adequate evidence to determine the optimal screening interval in children aged 3 to 5 years.
Treatment depends on the specific condition and includes correction of any underlying refractive error with the use of corrective lenses, occlusion therapy for amblyopia (eg, eye patching, atropine eye drops, or Bangerter occlusion foils), or surgical interventions for some causes of refractory strabismus.
Suggestions for Practice Regarding the I Statement
Potential Preventable Burden
Untreated amblyopia is not likely to spontaneously resolve.1,16,17 Treatment efficacy decreases with age, with a risk of irreversible vision loss.1,18,20 Untreated vision abnormalities can result in short- and long-term physical and psychological harms, such as accidents and injuries, experiencing bullying behaviors, poor visual motor skills, depression and anxiety, poor self-esteem, and problems at school and work.21-25
Vision screening is routinely offered in most primary care settings. Screening rates among children aged 3 years are approximately 40% and increase with age.1,26 One survey reported that 3% of pediatricians began vision screening at age 6 months.1,26 Typical components of vision screening include assessments of visual acuity and strabismus. Younger children (<3 years) are often unable to cooperate with some of the clinical screening tests performed in clinical practice, such as visual acuity testing, which may result in false-positive results. Some clinical practice guidelines now recommend using handheld autorefractors and photoscreeners as alternative approaches to screening in children 6 months and older because of improved child cooperation and improved accuracy.1,28
One potential disadvantage of using some types of photoscreeners is the need for external interpretation of screening results. Children with positive findings should be referred for a complete eye examination to confirm the presence of vision abnormalities and for further treatment.
Research Needs and Gaps
The USPSTF identified several gaps in the evidence. Well-designed trials are needed to better understand the effects of screening vs no screening, the optimal age for initiation of screening, and appropriate screening intervals. Additional studies are needed to determine the best screening approach and most favorable combinations of screening tests in primary care. There is also a need for studies that examine the benefits and harms of vision screening and treatment in children younger than 3 years and the long-term benefits and harms of preschool vision screening on health outcomes, such as quality of life, school performance, developmental trajectory, and functioning.
Update of Previous USPSTF Recommendation
This recommendation is an update of the USPSTF 2011 recommendation,32 in which the USPSTF recommended vision screening for amblyopia and its risk factors in children aged 3 to 5 years (B recommendation). The USPSTF concluded that the evidence was insufficient to assess the balance of benefits and harms of vision screening in children younger than 3 years (I statement). The current recommendation reaffirms the previous recommendation.
One of the most important causes of vision abnormalities in children is amblyopia (also known as “lazy eye”). Amblyopia is an alteration in the visual neural pathway in a child’s developing brain that can lead to permanent vision loss in the affected eye.1,2 It usually occurs in 1 eye but can occur in both. Risk factors associated with the development of amblyopia include strabismus (ocular misalignment); vision deprivation caused by media opacity (eg, cataracts); high, uncorrected refractive errors (eg, myopia, hyperopia, and astigmatism); and anisometropia (Table 1). Other common causes of vision abnormalities are nonamblyopic strabismus and nonamblyopic refractive error.1 Among children younger than 6 years, 1% to 6% have amblyopia or its risk factors (strabismus, anisometropia, or both), which, if left untreated, could lead to amblyopia.1,3-7 Early identification of vision abnormalities could prevent the development of amblyopia.
The USPSTF found adequate evidence that vision screening tools are accurate in detecting vision abnormalities, including refractive errors, strabismus, and amblyopia. The USPSTF found inadequate evidence to compare screening accuracy across age groups (<3 vs ≥3 years). Many studies of clinical accuracy did not enroll children younger than 3 years.
Benefits of Early Detection and Treatment
The USPSTF found adequate evidence that treatment of amblyopia or its risk factors in children aged 3 to 5 years leads to improved visual acuity. The USPSTF determined that the magnitude of improvement in visual acuity is of moderate benefit. The USPSTF found inadequate evidence that treatment reduced the incidence of long-term amblyopia or improved school performance, functioning, or quality of life. Limited evidence suggests that screening can potentially reduce psychosocial harms. The USPSTF found inadequate evidence that treatment of amblyopia or its risk factors in children younger than 3 years leads to improved vision outcomes (ie, visual acuity) or other benefits.
Harms of Early Detection and Treatment
The USPSTF found adequate evidence to assess harms of vision screening tests in children aged 3 to 5 years, including higher false-positive rates in low-prevalence populations. False-positive screening results may lead to overdiagnosis or unnecessary treatment. Limited evidence suggests that eye patching in children aged 3 to 5 years does not worsen visual acuity in the nonamblyopic eye but may be associated with psychological harms, such as child or parental upset or concern. The USPSTF found adequate evidence to bound the potential harms of vision screening and treatment in children aged 3 to 5 years as small, based on the nature of the interventions. The USPSTF found inadequate evidence on the harms of treatment in children younger than 3 years.
The USPSTF concludes with moderate certainty that vision screening to detect amblyopia or its risk factors in children aged 3 to 5 years has a moderate net benefit. The USPSTF concludes that the benefits of vision screening to detect amblyopia or its risk factors in children younger than 3 years are uncertain, and that the balance of benefits and harms cannot be determined for this age group.
Recommendations of OthersIn 2016, the American Academy of Pediatrics, American Association for Pediatric Ophthalmology and Strabismus, American Academy of Certified Orthoptists, and American Academy of Ophthalmology released a joint clinical report recommending preschool vision screening.41 The joint report recommends vision assessment in children aged 6 months to 3 years with physical examination (eg, external inspection, the fixation and follow test, the red reflex test, and pupil examination). Instrument-based vision screening (with autorefractors or photoscreeners) may be used, when available, in children aged 1 to 3 years. Visual acuity screening may be attempted at age 3 years using HOTV or Lea Symbols charts; children aged 4 to 5 years should have visual acuity assessed using HOTV or Lea Symbols charts, the cover-uncover test, and the red reflex test.1,41 The American Academy of Family Physicians recommends vision screening in all children at least once between the ages of 3 and 5 years to detect amblyopia or its risk factors; it concluded that the current evidence is insufficient to assess the balance of benefits and harms of vision screening in children younger than 3 years.42 The American Optometric Association recommends initial vision screening in infants at birth. Regular comprehensive eye examinations should occur at age 6 months, age 3 years, and prior to entry into first grade; eye examinations should then occur at 2-year intervals unless children are considered at high risk for vision abnormalities.43