Effectiveness of Telescopic Magnification in the Treatment of Amblyopia

Amblyopia Clinical Trial

Official title:

Effectiveness of Telescopic Magnification in the Treatment of Amblyopia

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00970554
• Other study ID #: 1000011712
• Status: Completed
• Phase: Phase 1/Phase 2
• First received: September 1, 2009
• Last updated: August 26, 2013
• Start date: December 2007
• Est. completion date: May 2009

Study information

• Verified date: August 2013
• Source: The Hospital for Sick Children
• Contact: n/a
• Is FDA regulated: No
• Health authority: Canada: Ethics Review Committee
• Study type: Interventional

Clinical Trial Summary

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).

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 15
• Est. completion date: May 2009
• Est. primary completion date: May 2009
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 4 Years to 17 Years

Eligibility

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 Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Amblyopia

Intervention

Other:
• Patching
Patching of the sound eye for 30 minutes a day for 17 weeks.
• 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.

Locations

Country	Name	City	State
Canada	The Hospital for Sick Children	Toronto	Ontario

Sponsors (1)

Lead Sponsor	Collaborator
The Hospital for Sick Children

Country where clinical trial is conducted

Canada, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	The best corrected logMAR visual acuity score of the amblyopic eye.		17 weeks	No
Secondary	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.		17 weeks	No