Efficacy of Visual Screening in Ontario

NCT02458846 | Completed

• 1 other identifier: 1000045972
• Study Type: interventional
• Target: 2,597
• Locations: 1 country
• Sites: 1

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.

Conditions

Amblyopia

Outcome Measures

Primary Outcomes (3)

• Prevalence of amblyopia

  Prevalence of suspected amblyopia, defined as 2-or-greater line difference in acuity between eyes

  16 months

• Prevalence of refractive errors

  Untreated clinically significant refractive errors defined by AAPOS (2013) guidelines

  16 months

• Prevalence of reduced stereo vision

  Stereoacuity is often reduced in patients with some types of amblyopia, and will defined as worse than 30 arcsec

  16 months

Secondary Outcomes (2)

• Proportion of below-average readers Year 1

  10 months

• Proportion of below-average readers Year 2

  22 months

Study Arms (2)

Screened Schools

EXPERIMENTAL

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)

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

Care As Usual Schools

NO INTERVENTION

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)

Interventions

Crowded HOTV Acuity Test OTHER

This is one of the most sensitive tests of acuity for vision screening of young children. The child is asked to recognize a letter (H,O,T,V) that is surrounded by bars to induce the crowding effects typical of amblyopia. Children were tested monocularly and was required to achieve at least 20/32 in each eye to pass. Children already wearing glasses were tested with their glasses on.

Screened Schools

Preschool Randot Stereoacuity Test OTHER

This is a reliable screening test for stereo depth perception for young children. Children wear polarized stereoglasses and are asked to identify or match shapes that are "hiding in the snow", which cannot be perceived if the child has abnormal binocular vision. Children were required to achieve at least 60 arcseconds of disparity to pass. Children already wearing glasses were tested with their glasses worn under the stereo glasses.

Screened Schools

Plusoptix Autorefractor DEVICE

Autorefractors are electronic devices that measure refractive errors by focusing a light onto the child's eyes and recording how their reflections from the retina return to the camera. The Plusoptix has been shown to have high sensitivity and specificity in previous research. AAPOS (2013) guidelines were used to determine the referral criteria.

Screened Schools

Comprehensive Eye Exam OTHER

Children who did not pass all three screening tests were referred for full cycloplegic optometry exams, with a parent/guardian present. Optometrists assessed visual history, monocular visual acuity (near \& far), strabismus, binocular function, abnormalities of the anterior segment, and cycloplegic refraction. If the optometrist prescribed glasses, frames were chosen at the time of the exam and the glasses were dispensed either at school (with an optician) or at the optometrist's office.

Screened Schools

Eligibility Criteria

• Age: 3 Years - 8 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• Screening: children enrolled in senior kindergarten (age 5-6 years)
• Follow-up: children enrolled in Grade 2 (age 7-8 years)

You may not qualify if:

• None

Sponsors & Collaborators

• The Hospital for Sick Children: lead

Study Sites (1)

The Hospital for Sick Children

Toronto, Ontario, M5G 1X8, Canada

Location

MeSH Terms

Conditions

Amblyopia

Condition Hierarchy (Ancestors)

Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Vision Disorders; Sensation Disorders; Neurologic Manifestations; Eye Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Officials

• Agnes Wong

  The Hospital for Sick Children

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Senior Scientist; Neurosciences and Mental Health

Study Record Dates

• First Submitted: January 8, 2015
• First Posted: June 1, 2015
• Study Start: September 1, 2014
• Primary Completion: December 15, 2019
• Study Completion: December 15, 2019
• Last Updated: March 19, 2020

Record last verified: 2020-03

Locations

CA (1)