Effectiveness of Telescopic Magnification in the Treatment of Amblyopia

August 26, 2013 updated by: Agnes Wong, The Hospital for Sick Children
Amblyopia is a visual impairment of one eye that results from disuse of that eye during early brain development. The standard treatment for amblyopia consists of patching or pharmacological penalization of the sound eye. Unfortunately, approximately 50% of amblyopic children do not respond to these therapies, with poor compliance being a major factor in treatment failure. One new treatment strategy involves patching the sound eye while using a telescopic device on the amblyopic eye to magnify the images formed in the amblyopic eye. Children were randomized to receive either daily patching of the sound eye for 30 minutes only (patching only group), or daily patching of the sound eye for 30 minutes plus simultaneous use of a telescopic device by the amblyopic eye during patching (patching plus telescope group).

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The goal of the present investigation was to conduct a prospective randomized clinical study to further evaluate the effectiveness of telescopic magnification plus patching vs patching alone on different types of amblyopia in patients who had failed previous treatment.

Study Type

Interventional

Enrollment (Actual)

15

Phase

  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Toronto, Ontario, Canada
        • The Hospital for Sick Children

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

4 years to 17 years (Child)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Aged 4-17 years

  • Strabismic, refractive (anisometropic), isometropic or mixed mechanism amblyopia

    • Strabismic amblyopia is defined as amblyopia (1) in the presence of either an inability to maintain parallel visual axes (heterotropia) at distance or near fixation or both, or a history of strabismus surgery (or botulinum injection), and (2) in the absence of refractive error meeting the criteria below for mixed mechanism amblyopia
    • Refractive/Anisometropic amblyopia is defined as amblyopia in the presence of a difference in refractive error between the two eyes (anisometropia) of ≥0.5 diopter (D) of spherical equivalent or ≥1.5D of difference in astigmatism in any meridian, with no measurable heterophoria at distance or near fixation, which persisted after 12 weeks of spectacle correction
    • Isometropic amblyopia is defined as amblyopia in the presence a refractive error ≥5.0D of spherical equivalent in both eyes, but not meeting the criteria of anisometropic amblyopia
    • Mixed mechanism strabismic and refractive amblyopia is defined as the presence of both strabismic and anisometropic types of amblyopia
  • Ability to read the ETDRS letter chart
  • Visual acuity between 0.3 and 1.3 logMAR (i.e., between 20/40 and 20/400) in the amblyopic eye
  • Visual acuity of 0.3 logMAR (i.e., 20/40) or better in the sound eye
  • Interocular acuity difference ≥0.3 logMAR
  • Appropriate refractive error correction for at least 12 weeks

Exclusion Criteria:

  • Presence of an ocular cause of reduced visual acuity
  • Myopia with a spherical equivalent of -6.0D or more, due to the likely presence of pathological myopia
  • Prior intraocular surgery
  • Known skin reaction to patch or bandage adhesive

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Patching only
Other: Patching
Patching of the sound eye for 30 minutes a day for 17 weeks.
Experimental: Patching plus telescope group
Other: Telescopic magnification
Patching of the sound eye plus simultaneous use of a telescopic device by the amblyopic eye for 30 minutes a day for 17 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
The best corrected logMAR visual acuity score of the amblyopic eye.
Time Frame: 17 weeks
17 weeks

Secondary Outcome Measures

Outcome Measure
Time Frame
Visual acuity of at least 0.2 logMAR (20/30) and/or improvement of at least 0.2 logMAR from baseline in the amblyopic eye.
Time Frame: 17 weeks
17 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

The Hospital for Sick Children

Investigators

  • Principal Investigator: Agnes Wong, MD, The Hospital for Sick Children, Toronto, Canada

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

December 1, 2007

Primary Completion (Actual)

May 1, 2009

Study Completion (Actual)

May 1, 2009

Study Registration Dates

First Submitted

September 1, 2009

First Submitted That Met QC Criteria

September 1, 2009

First Posted (Estimate)

September 2, 2009

Study Record Updates

Last Update Posted (Estimate)

August 27, 2013

Last Update Submitted That Met QC Criteria

August 26, 2013

Last Verified

August 1, 2013

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 1000011712

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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