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New Visual Acuity and Crowding Tests for Better Detection of Amblyopia

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ClinicalTrials.gov Identifier: NCT03505606
Recruitment Status : Recruiting
First Posted : April 23, 2018
Last Update Posted : February 1, 2019
Sponsor:
Information provided by (Responsible Party):
Anglia Ruskin University

Brief Summary:

Amblyopia, or 'lazy eye', is the reduction in vision usually in one eye, due to abnormal visual development without organic cause. It is a preventable and leading cause of monocular vision loss (prevalence of around 3%) and increases lifetime risk of bilateral visual impairment from 10% in the general population, to 18% in amblyopes.

In the UK, vision screening in children aims to detect amblyopia and other undiagnosed visual conditions. Laboratory research suggest that amblyopia could be better detected by modifying standard clinical vision tests to enhance and quantify "crowding". Crowding is the negative effect that surrounding features have on the visibility of a target. Crowding distance and crowding magnitude are considerably greater in amblyopic eyes than in normal healthy eyes. Modifications that should lead to improved amblyopia detection are 1) place letters closer together on a vision chart, 2) define letters by contrast, rather than luminance, and 3) use a new thinner font in the form of numbers, to allow crowding distance in central vision to be measured. In this project, these modifications will be tested in amblyopic children for the first time.

Amblyopic children aged 3 to 11 years (n=32) will be recruited from ACPOS (Addenbrooke's Community Paediatric Ophthalmology Service) at ARU. They will have their vision measured with the three modified tests as well as an uncrowded test. The child will view letters and numbers on a computer screen and respond (verbally or by indicating their choice on a matching card). Testing is fun and game-like with breaks for rewards. Results will be compared to standard vision measurement (SLT: Sonksen LogMAR Test) from the child's ACPOS visit. Amblyopic data will be compared to control data from normal healthy children aged 3 to 11 years (n=200), and age-matched children with normal vision (n=16) from ACPOS (false referrals from school screening).


Condition or disease Intervention/treatment Phase
Amblyopia Diagnostic Test: Visual acuity tests Not Applicable

  Show Detailed Description

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 48 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Diagnostic
Official Title: Examination of New Visual Acuity and Clinical Crowding Tests for Better Detection of Amblyopia
Actual Study Start Date : January 1, 2019
Estimated Primary Completion Date : December 2020
Estimated Study Completion Date : December 2020

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Amblyopia

Arm Intervention/treatment
Active Comparator: Control
Visual acuity tests on control participants
Diagnostic Test: Visual acuity tests
Participants to have visual acuity tested with the three modified vision tests.
Other Names:
  • Contrast-modulated Cambridge Crowding test
  • Crowding Distance Test
  • Enhanced Cambridge Crowding test

Experimental: Amblyopic
Visual acuity tests on amblyopic participants.
Diagnostic Test: Visual acuity tests
Participants to have visual acuity tested with the three modified vision tests.
Other Names:
  • Contrast-modulated Cambridge Crowding test
  • Crowding Distance Test
  • Enhanced Cambridge Crowding test




Primary Outcome Measures :
  1. Visual Acuity [ Time Frame: Vision measured at the time of testing. ]
    LogMAR



Information from the National Library of Medicine

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Ages Eligible for Study:   3 Years to 11 Years   (Child)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Test participants; Male and female 3 to 11-year-old children diagnosed by ACPOS clinicians as likely having amblyopia (strabismic or anisometropic). They will be tested following 6 weeks (or more) of refractive adaption.
  • Control Participants; Male and female 3 to 11-year-old children who have been falsely referred into the Hospital Eye Service (ACPOS) by the visual screening service, but have satisfactory visual functions, as per the national screening guidelines.
  • All participants must be able to complete the Sonsken logMAR Test (SLT) either verbally or via use of a matching card.

Exclusion Criteria:

  • Uncorrected refractive error.
  • The presence of any other vision limiting medical condition, not listed in the inclusion criteria.
  • Any prior or existing medical history of epilepsy or seizures.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03505606


Contacts
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Contact: Louisa A Haine, MMedSci 01223 698584 louisa.haine@anglia.ac.uk

Locations
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United Kingdom
Anglia Ruskin University Eye Clinic Recruiting
Cambridge, Cambridgeshire, United Kingdom, CB11PT
Contact: Louisa A Haine, MMedSci    01223 698584    louisa.haine@anglia.ac.uk   
Principal Investigator: Louisa A Haine, MMedSci         
Sponsors and Collaborators
Anglia Ruskin University
Investigators
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Study Director: Sarah Waugh, PhD Anglia Ruskin University

Publications:

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Responsible Party: Anglia Ruskin University
ClinicalTrials.gov Identifier: NCT03505606     History of Changes
Other Study ID Numbers: FST/FREP/17/739
First Posted: April 23, 2018    Key Record Dates
Last Update Posted: February 1, 2019
Last Verified: January 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided
Plan Description: Pseudo-anonymised data to be uploaded to ARRO, the university data storage system.

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No

Keywords provided by Anglia Ruskin University:
Amblyopia
Visual Acuity
Crowding

Additional relevant MeSH terms:
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Amblyopia
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Vision Disorders
Sensation Disorders
Neurologic Manifestations
Eye Diseases
Signs and Symptoms