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Effectiveness of Telescopic Magnification in the Treatment of Amblyopia

This study has been completed.
Sponsor:
ClinicalTrials.gov Identifier:
NCT00970554
First Posted: September 2, 2009
Last Update Posted: August 27, 2013
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by (Responsible Party):
Agnes Wong, The Hospital for Sick Children
  Purpose
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).

Condition Intervention Phase
Amblyopia Other: Patching Other: Telescopic magnification Phase 1 Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Effectiveness of Telescopic Magnification in the Treatment of Amblyopia

Resource links provided by NLM:


Further study details as provided by Agnes Wong, The Hospital for Sick Children:

Primary Outcome Measures:
  • The best corrected logMAR visual acuity score of the amblyopic eye. [ Time Frame: 17 weeks ]

Secondary Outcome Measures:
  • 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 ]

Enrollment: 15
Study Start Date: December 2007
Study Completion Date: May 2009
Primary Completion Date: May 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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.

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.
  Eligibility

Information from the National Library of Medicine

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Ages Eligible for Study:   4 Years to 17 Years   (Child)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

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
  Contacts and Locations
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): NCT00970554


Locations
Canada, Ontario
The Hospital for Sick Children
Toronto, Ontario, Canada
Sponsors and Collaborators
The Hospital for Sick Children
Investigators
Principal Investigator: Agnes Wong, MD The Hospital for Sick Children, Toronto, Canada
  More Information

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Agnes Wong, Ophthamologist-In-Chief, The Hospital for Sick Children
ClinicalTrials.gov Identifier: NCT00970554     History of Changes
Other Study ID Numbers: 1000011712
First Submitted: September 1, 2009
First Posted: September 2, 2009
Last Update Posted: August 27, 2013
Last Verified: August 2013

Keywords provided by Agnes Wong, The Hospital for Sick Children:
Amblyopia
Telescopic magnification
Patching

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