The Efficacy of a Visual Screening Program to Reduce Later Amblyopia and Untreated Refractive Errors
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Enrollment
- 2,597
- Locations
- 1
- Primary Endpoint
- Prevalence of reduced stereo vision
Study Overview
Brief Summary
Amblyopia (lazy eye), is the leading treatable cause of vision loss in childhood. Uncorrected refractive errors (ie farsightedness) can lead to difficulties in school. Unfortunately, many children do not receive vision screening until they have already developed irreversible vision problems. We will conduct a cluster randomized clinical trial in which schools, not individual children, are randomly allocated to receive a kindergarten visual screening program or to receive no intervention by the research team (i.e., "care as usual"). We will compare the prevalence of visual problems (and proportion of children with reading problems) when the children are in Grade 2, after allowing for at least one year of treatment.
Detailed Description
The proposed study is a single-masked cluster randomized clinical trial, with randomization and analyses occurring at the level of "schools" (i.e., we are not randomly assigning individuals to groups). To assess the efficacy of a visual screening program, we will compare visual outcomes in 25 schools randomly chosen to receive the program and 25 schools allocated to "care as usual" one year after screening. The screening tools are HOTV crowded acuity, Preschool Randot Stereoacuity Test, and Plusoptix Autorefractor. The outcome measures will assess later differences between schools receiving the visual screening program and control schools for prevalence of (1) visual and (2) reading problems. A lower prevalence of either or both problems in schools where the visual screening program was offered would provide evidence for the efficacy of vision screening. Primary outcome measure is the prevalence of amblyopia, reduced stereo vision, and untreated clinically significant refractive errors in "screened" versus "care as usual" schools. Secondary outcome measure is the proportion of children performing 1 standard deviation below average on reading scores in "screened" versus "care as usual" schools.
Study Design
- Study Type
- Interventional
- Allocation
- Non Randomized
- Intervention Model
- Single Group
- Primary Purpose
- Diagnostic
- Masking
- None
Eligibility Criteria
- Ages
- 3 Years to 8 Years (Child)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Screening: children enrolled in senior kindergarten (age 5-6 years)
- •Follow-up: children enrolled in Grade 2 (age 7-8 years)
Exclusion Criteria
- Not provided
Arms & Interventions
Screened Schools
25 schools. Screening involved: crowded HOTV acuity test, Preschool Randot Stereoacuity Test, and Plusoptix autorefractor. Referral criteria followed AAPOS guidelines for screening for amblyopia and amblyopia risk factors. Children who fail any one of the three tests (including uncooperative/unable children) will be given a referral letter, which includes an assigned appointment time for a comprehensive eye exam at school with a licensed optometrist. Any needed glasses will be dispensed at no cost to the parents. 6 months after the eye exam, we will follow up with a phone call to parents to offer any additional support (such as replacing broken/lost glasses)
Intervention: Crowded HOTV Acuity Test (Other)
Screened Schools
25 schools. Screening involved: crowded HOTV acuity test, Preschool Randot Stereoacuity Test, and Plusoptix autorefractor. Referral criteria followed AAPOS guidelines for screening for amblyopia and amblyopia risk factors. Children who fail any one of the three tests (including uncooperative/unable children) will be given a referral letter, which includes an assigned appointment time for a comprehensive eye exam at school with a licensed optometrist. Any needed glasses will be dispensed at no cost to the parents. 6 months after the eye exam, we will follow up with a phone call to parents to offer any additional support (such as replacing broken/lost glasses)
Intervention: Preschool Randot Stereoacuity Test (Other)
Screened Schools
25 schools. Screening involved: crowded HOTV acuity test, Preschool Randot Stereoacuity Test, and Plusoptix autorefractor. Referral criteria followed AAPOS guidelines for screening for amblyopia and amblyopia risk factors. Children who fail any one of the three tests (including uncooperative/unable children) will be given a referral letter, which includes an assigned appointment time for a comprehensive eye exam at school with a licensed optometrist. Any needed glasses will be dispensed at no cost to the parents. 6 months after the eye exam, we will follow up with a phone call to parents to offer any additional support (such as replacing broken/lost glasses)
Intervention: Plusoptix Autorefractor (Device)
Care As Usual Schools
25 schools were randomly allocated to the "care as usual" schools. No intervention was provided by the research team, however, children may have received optometry/ophthalmology care via regular referral channels (e.g., family physicians, teachers)
Screened Schools
25 schools. Screening involved: crowded HOTV acuity test, Preschool Randot Stereoacuity Test, and Plusoptix autorefractor. Referral criteria followed AAPOS guidelines for screening for amblyopia and amblyopia risk factors. Children who fail any one of the three tests (including uncooperative/unable children) will be given a referral letter, which includes an assigned appointment time for a comprehensive eye exam at school with a licensed optometrist. Any needed glasses will be dispensed at no cost to the parents. 6 months after the eye exam, we will follow up with a phone call to parents to offer any additional support (such as replacing broken/lost glasses)
Intervention: Comprehensive Eye Exam (Other)
Outcomes
Primary Outcomes
Prevalence of reduced stereo vision
Time Frame: 16 months
Stereoacuity is often reduced in patients with some types of amblyopia, and will defined as worse than 30 arcsec
Prevalence of refractive errors
Time Frame: 16 months
Untreated clinically significant refractive errors defined by AAPOS (2013) guidelines
Prevalence of amblyopia
Time Frame: 16 months
Prevalence of suspected amblyopia, defined as 2-or-greater line difference in acuity between eyes
Secondary Outcomes
- Proportion of below-average readers Year 1(10 months)
- Proportion of below-average readers Year 2(22 months)
Investigators
Agnes Wong
Senior Scientist; Neurosciences and Mental Health
The Hospital for Sick Children