None listed
Conditions
Brief summary
Amblyopia, also known as lazy eye, is a developmental disorder of vision whereby the brain ignores the information from one eye. This leads to a reduction in the vision of that eye. Also, the two eyes fail to work together resulting in a lack of binocular vision. This study is designed to test a new treatment for amblyopia implemented as a videogame on an iPod touch device that aims to strengthen binocular vision. The treatment is expected to establish stereopsis (3D vision) and to improve monocular acuity in participants with lazy eye. Participants will be given real or placebo treatment for 6 weeks and standard clinical tests of monocular and binocular vision will be used to assess treatment outcomes.
Interventions
Participants will be provided with an iPod touch device loaded with a modified version of the videogame Tetris and will be asked to play for 1 to 2 hours per day for a total of 6 weeks while wearing red/green anaglyphic glasses. The Tetris blocks will be presented so that some blocks are seen by the amblyopic eye and other blocks are seen by the fellow (non-amblyopic) eye by means of red/green anaglyphic glasses. Tetris blocks will be presented to the amblyopic eye at 100% contrast and to the fe
Participants will be provided with an iPod touch device loaded with a modified version of the videogame Tetris and will be asked to play for 1 to 2 hours per day for a total of 6 weeks while wearing red/green anaglyphic glasses. The Tetris blocks will be presented so that some blocks are seen by the amblyopic eye and other blocks are seen by the fellow (non-amblyopic) eye by means of red/green anaglyphic glasses. Tetris blocks will be presented to the amblyopic eye at 100% contrast and to the fellow eye at a contrast determined by a random dot kinematogram measure of suppression at the start of training. The contrast of the blocks presented to the fellow eye will be increased if patients play the game successfully. Specifically, if the patient successfully completes 3 or more levels of the game within 24 hours the contrast to the fellow eye will be increased by 10% for the next 24 period of play. If the game is attempted and 3 or more levels are not successfully completed the contrast presented to the fellow eye will be reduced by 5%. The time participants spend playing the game will be automatically recorded on the iPod device.
Sponsors
The University of Auckland
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
7 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Amblyopia associated with the presence or history of strabismus, anisometropia or both (mixed mechanism). * Unilateral amblyopia, defined as best corrected visual acuity (VA) in the amblyopic eye of 0.3-1.0 logMAR inclusive, measured using the E-ETDRS protocol from the Electronic Visual Acuity (EVA) testers, VA in the fellow eye equal to or less than 0.1 logMAR and an interocular VA difference equal to or greater than 0.2 log units * Strabismic amblyopia, defined as amblyopia in the presence of heterotropia distance and/or near fixation, a history of strabismus surgery, or resolution of misalignment following hyperopic spectacle correction, with a spherical equivalent difference < 1.00D between the eyes and a difference in astigmatism in any meridian < 1.50D between the eyes * Anisometropic amblyopia, defined as amblyopia in the presence of a spherical equivalent difference equal to or greater than 0.50D between the eyes, or a difference of astigmatism in any meridian equal to or greater than 1.50D * Mixed mechanism amblyopia, defined as amblyopia in the presence of a heterotropia at distance and/or near fixation, a history of strabismus surgery, or a history of resolution of misalignment following a hyperopic spectacle correction and a spherical equivalent difference equal to or greater than 1.00D between the eyes or a difference in astigmatism in any meridian equal to or greater than 1.50D between the eyes * An ability to align the images shown to each eye on the iPod device under normal binocular viewing conditions in order to successfully play the game as part of their treatment * Refractive corrections meet the following criteria and are based on a cycloplegic refraction that is not more than six months old (a new cycloplegic refraction will be provided if necessary): 1) Hypermetropia will not be under-corrected by more than +1.50D spherical equivalent and the reduction in plus sphere must be identical between the two eyes. 2) Spherical equivalent power will be equal to or less than +/-0.50D of fully correcting the anisometropia. 3) Cylinder power in each eye will be equal to or less than +/-0.50D of fully correcting the astigmatism for each eye. 4) Cylinder axis in the spectacle lenses in both eyes must be equal to or less than +/-6 degrees of the axis of the cycloplegic refraction when cylinder power is equal to or greater than 1.00 D. Spectacles meeting the above criteria will have been worn either for 16 weeks prior to the baseline visit or until visual acuity is stable (a change equal to or less than 0.1 log units over two measurements made at least four weeks apart) through the refractive adaptation period in this study * Willing and being able to provide written informed consent for participation in the study
Exclusion criteria
Myopia > 6.00D, previous intraocular surgery, any co-existent ocular pathology, known neurological anomalies and an inability to align the images shown to each eye on the iPod device.
Outcome results
None listed