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Final Research Plan

Final Research Plan for Vision in Children Ages 6 Months to 5 Years: Screening

Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.

The final Research Plan will be used to guide a systematic review of the evidence by researchers at an Evidence-based Practice Center. The resulting Evidence Review will form the basis of the USPSTF Recommendation Statement on this topic.

The draft Research Plan was available for comment from September 24 until October 21, 2015 at 8:00 p.m., ET. 

Analytic Framework

Abbreviation: KQ=key question.

* Amblyogenic risk factors include anisometropia, strabismus, hyperopia, any media opacity, astigmatism, ptosis, and abnormal visual acuity (including substantial isoametropic refractive error).
† Determination of refractive error will be based on age-appropriate standards.

Text Description.

This figure is the analytic framework depicting the five key questions and the research approach that will guide the evidence review outlined in this research plan. In general, the figure illustrates the overarching question (key question 1) of whether screening for amblyopia, its risk factors, and refractive error in children ages 6 months to 5 years leads to improved health outcomes. The framework starts on the left with the patient population of interest: children ages 6 months to 5 years. Moving from left to right, the figure depicts the availability of vision screening tools and the accuracy and reliability of such tools (key question 2). There are the potential harms of screening (key question 3). For children with amblyopia, its risk factors, or refractive error, treatment may improve health outcomes, such as visual acuity, reduced long-term amblyopia, school performance, functioning, and quality of life (key question 4). Treatment may also result in harms (key question 5).

Key Questions to Be Systematically Reviewed

1. Does screening for amblyopia, its risk factors, and refractive error in children ages 6 months to 5 years reduce long-term amblyopia or improve visual acuity, school performance, functioning, and/or quality of life?
   a. Does the effectiveness of screening in children ages 6 months to 5 years vary among different age groups?
2. What is the accuracy and reliability of screening tests for amblyopia, its risk factors, and refractive error in children ages 6 months to 5 years?
   a. Does the accuracy or reliability of screening tests for amblyopia, its risk factors, and refractive error vary among different age groups?
3. What are the harms of screening for amblyopia, its risk factors, and refractive error in children ages 6 months to 5 years?
4a. Does treatment of amblyopia, its risk factors, and refractive error in children ages 6 months to 5 years improve visual acuity?
4b. Does treatment of amblyopia, its risk factors, and refractive error in children ages 6 months to 5 years reduce long-term amblyopia or improve school performance, functioning, and/or quality of life?
5. What are the harms of treatment of amblyopia, its risk factors, and refractive error in children ages 6 months to 5 years?

Contextual Question

Contextual questions will not be systematically reviewed and are not shown in the Analytic Framework.

  1. What are the minimal clinically perceptible and clinically meaningful changes in visual acuity?

Research Approach

The Research Approach identifies the study characteristics and criteria that the Evidence-based Practice Center will use to search for publications and to determine whether identified studies should be included or excluded from the Evidence Review. Criteria are overarching as well as specific to each of the key questions (KQs).

  Include Exclude
Populations All KQs: Children ages 6 months to 5 years

KQs 1–3: Children without known impaired visual acuity or obvious symptoms of impaired visual acuity

KQs 4, 5: Children with amblyopia, amblyogenic risk factors, and/or refractive error
Newborns, children younger than age 6 months, and children age 6 years and older; children with severe congenital conditions or developmental delays, retinopathy of prematurity, glaucoma, congenital cataract, neurodevelopmental disorders, systemic conditions associated with ocular abnormalities, or pathologic myopia
Setting All KQs: Studies performed in primary care, community-based, and school settings; studies conducted in countries categorized as “Very High” on the Human Development Index, as defined by the United Nations Development Programme

KQs 2–5: Specialty settings (e.g., ophthalmology or optometry practices)

 
Screening tests and interventions KQs 1–3: Studies of screening tests used or available in primary care settings, including: visual acuity tests (e.g., autorefraction; picture identification tests, such as Allen test cards or Lea symbols; HOTV chart; Snellen chart; tumbling E chart), stereoacuity tests (e.g., contour stereotests, such as the Frisby, Random Dot E, Stereo Smile, and Titmus Fly tests; Moving Dynamic Random Dot Stereosize test), and ocular alignment tests (e.g., photoscreening, corneal light reflex test, cover-uncover test, cross cover test, red reflex test)

KQs 4, 5: Correction of refractive error (eyeglasses); penalization of the nonamblyogenic eye (eye patch, atropine); and vision therapy (eye exercises)

KQs 1–3: Studies of screening tests not used or available in primary care settings (e.g., contrast sensitivity test, fundoscopic examination, visual acuity test with cyclopegia) or not intended to detect amblyopia, amblyogenic risk factors, or refractive error (e.g., white reflex test)

KQs 4, 5: Surgical interventions for strabismus or other indications

Comparisons KQs 1,3: Screened vs. nonscreened groups or screening at a younger vs. older age

KQ 2: Evaluations that include cycloplegic refraction and/or a comprehensive eye examination; for evaluations of reliability (test-retest), the comparison may be the same test administered at different timepoints or by a different person

KQs 4, 5: No treatment or sham or inactive control

No comparison; nonconcordant historical controls; comparative studies of various interventions (i.e., head-to-head studies without an additional eligible comparison group)
Outcomes KQs 1, 4: Reduced long-term amblyopia and improved visual acuity, school performance, functioning, and quality of life

KQ 2: Sensitivity, specificity, positive and negative predictive values, likelihood ratios, and diagnostic odds ratios (or ability to calculate such outcomes from data provided); measures of reliability, including reproducibility, interrater reliability, and testability (ability of children to cooperate with the test)

KQs 3, 5: Harms, including psychological distress, labeling, anxiety, other psychological effects, false-positive results, and adverse effects on vision in the nonimpaired eye

Cost-effectiveness or cost-related outcomes

KQ 2: Studies only providing associations, correlations, or other outcomes

Study designs KQ 1: Randomized, controlled trials and prospective cohort studies with an eligible comparator

KQ 2: Cross-sectional studies, cohort studies, or trials focused on assessment of diagnostic accuracy

KQs 3, 5: Randomized, controlled trials; controlled cohort studies; case-control studies

KQ 4: Randomized, controlled trials

Case reports, case series, systematic reviews, and all other study designs not listed as eligible

KQ 2: Studies that do not attempt to perform the reference standard in all participants or a random sample of participants

Language and Publication status English-language, full-text journal articles Languages other than English; publications available only as a conference abstract

Response to Public Comment

The draft Research Plan was posted for public comment on the USPSTF Web site from September 24 to October 21, 2015. In response to comments, the USPSTF changed the title of the topic to “Vision Screening in Children Ages 6 Months to 5 Years” and replaced the term “visual impairment” with “amblyopia, its risk factors, and refractive error.” The USPSTF also added the term “clinically meaningful” to the contextual question and added children with neurodevelopmental disorders and systemic conditions associated with ocular abnormalities to the list of excluded populations in the research approach.

Appendix: Glossary of Terms

Amblyopia: A neurodevelopmental disorder that arises from abnormal processing of visual images during a critical period of vision development, resulting in a functional reduction of visual acuity.

Ametropia: An abnormal refractive condition (such as myopia, hyperopia, or astigmatism) of the eye in which images fail to focus upon the retina; also referred to as refractive error.

Anisometropia: A difference in refractive power between the eyes in which one foveal image is more blurred than the other.

Astigmatism: Blurred vision caused by a failure to focus light evenly onto the retina because of deviation from normal spherical curvature.

Cataract: A clouding or loss of transparency of the lens in the eye as a result of tissue breakdown and protein clumping.

Hyperopia: A condition in which visual images come to a focus behind the retina of the eye and vision is better for distant than near objects.

Isoametropia: An abnormal refractive condition occurring in both eyes.

Myopia: A condition in which visual images come to a focus in front of the retina of the eye because of defects in the refractive media or abnormal length of the eyeball, resulting especially in defective vision for distant objects.

Ptosis: Drooping of the upper eyelid due to paralysis, disease, or a congenital condition.

Stereopsis: The perception of depth produced by the reception in the brain of visual stimuli from both eyes in combination; also known as binocular vision.

Strabismus: Ocular misalignment in which each eye does not have the same image on the fovea.

Visual acuity: Sharpness of vision, measured by the ability to discern letters or numbers at a given distance according to a fixed standard.

Current as of: December 2015

Internet Citation: Final Research Plan: Vision in Children Ages 6 Months to 5 Years: Screening. U.S. Preventive Services Task Force. December 2015.
https://www.uspreventiveservicestaskforce.org/Page/Document/final-research-plan/vision-in-children-ages-6-months-to-5-years-screening

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