Efficacy of Visual Screening in Ontario

Not Applicable

Completed

• Conditions: Amblyopia
• Interventions: Other: Crowded HOTV Acuity Test; Other: Preschool Randot Stereoacuity Test; Device: Plusoptix Autorefractor; Other: Comprehensive Eye Exam

• Registration Number: NCT02458846
• Lead Sponsor: The Hospital for Sick Children

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 Timeline

• Study Start: 2014-09
• Study First Submitted: 2015-01-08
• Study First Submitted QC: 2015-05-27
• Study First Posted: 2015-06-01
• Primary Completion: 2019-12-15
• Study Completion: 2019-12-15
• Status Verified: 2020-03
• Last Update Submitted: 2020-03-17
• Last Update Posted: 2020-03-19

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 2597

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

• None

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Screened Schools	Comprehensive Eye Exam	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)
Screened Schools	Crowded HOTV Acuity Test	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)
Screened Schools	Preschool Randot Stereoacuity Test	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)
Screened Schools	Plusoptix Autorefractor	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)

Primary Outcome Measures

Name	Time	Method
Prevalence of reduced stereo vision	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	16 months	Untreated clinically significant refractive errors defined by AAPOS (2013) guidelines
Prevalence of amblyopia	16 months	Prevalence of suspected amblyopia, defined as 2-or-greater line difference in acuity between eyes

Secondary Outcome Measures

Name	Time	Method
Proportion of below-average readers Year 2	22 months	Proportion of Grade 2 children reading 1 SD below average
Proportion of below-average readers Year 1	10 months	Proportion of Grade 1 children reading 1 SD below average

Trial Locations

Locations (1)

The Hospital for Sick Children; 🇨🇦 Toronto, Ontario, Canada