Clinical Trial: Light-deprivation Utilized to Mitigate Amblyopia

Study Status: Active, not recruiting
Recruit Status: Active, not recruiting
Study Type: Interventional

Official Title: Optimized Visual Recovery in Adult Human Amblyopia Through Binocular Deprivation

Brief Summary: Amblyopia is an impairment in spatial vision caused by asymmetry in the quality of visual input across the two eyes during childhood. It is difficult to treat in adulthood because the visual system becomes less "plastic" (able to learn) with age. The purpose of this study is to determine whether five to ten days of visual deprivation--living in complete darkness--can enhance plasticity in the visual cortex and thereby facilitate the learning that is needed to recover visual function in amblyopic adults.

Detailed Summary:

An asymmetry in the visual input across the eyes early in postnatal life causes amblyopia, the most common basis of uni-ocular blindness in humans. If uncorrected, amblyopia results in the unaffected eye controlling the binocular visual cortex, while the ability of the affected eye to stimulate cortical neurons may weaken to the point of functional blindness. Previous attempts to recover vision in adult amblyopes have had limited success, and the investigators propose this is due in large part to the significant reduction of synaptic plasticity that occurs during cortical development. The investigators propose that optimal recovery from amblyopia in adulthood is a two stage process that requires 1) the reactivation of plasticity in the adult amblyopic cortex (permissive step) and 2) focused visual experience to stimulate perceptual learning (instructive step).

The Elizabeth Quinlan lab at the University of Maryland has recently shown that binocular visual deprivation in adulthood enhances synaptic plasticity in the adult cortex of experimental animals in as little as three days. In addition, binocular visual deprivation prior to repetitive visual experience stimulates the recovery of spatial acuity in an animal model of deep amblyopia. Here the investigators propose to translate this finding to the treatment of amblyopia in humans. The investigators propose to use binocular visual deprivation to promote synaptic plasticity in the amblyopic visual cortex, followed by visual perceptual learning through vision therapy homework, to stimulate the recovery of visual function. While visual perceptual learning has been previously shown to enhance visual function in amblyopic adults, the gains are slow and modest. The investigators predict that "pre-treatment" of the amblyopic visual system with binocular visual deprivation will enhance the magnitude and/or time course o
Sponsor: State University of New York College of Optometry

Current Primary Outcome:

• Change from baseline in Backus Lab Stereoacuity Assessment [ Time Frame: Twice during the two weeks before sequestration to establish baseline, and again after sequestration: twice weekly for 2 weeks, then weekly for 2 weeks, then 2 times during the next month, monthly for 4 months, and then once every two months for 6 months ]
  4-alternative forced choice task in a stereoscope in the Backus lab. Data will by analyzed for each participant separately and aggregated by mean of change over time.
• Change from baseline in contrast sensitivity function of amblyopic eye, fellow eye, and both eyes together, using the Sentio (R) CSF measurement device [ Time Frame: Twice during the two weeks before sequestration to establish baseline, and again after sequestration: twice weekly for 2 weeks, then weekly for 2 weeks, then 2 times during the next month, monthly for 4 months, and then once every two months for 6 months ]
  15-20 minute procedure to assess CSF in the amblyopic eye, fellow eye, and using both eyes together. Data will by analyzed for each participant separately and aggregated by mean of change over time.
• Change from baseline in acuity as measured using M&S Technologies automated ETDRS acuity test [ Time Frame: Three times during the 2 months before sequestration to establish baseline, and again after sequestration: once a week for 2 weeks, then once a month for 2 months, then once every 3 months until study completion (at approximately 1 year) ]
  5-10 minute procedure to assess logMAR acuity. Data will by analyzed for each participant separately and aggregated by mean of change over time.

Original Primary Outcome: Same as current

Current Secondary Outcome: Binocular motor fusion assessment [ Time Frame: 3 times during the 2 months before sequestration, 4 times during 12 months after sequestration ]

Original Secondary Outcome: Same as current

Information By: State University of New York College of Optometry

Dates:
Date Received: February 9, 2016
Date Started: October 2015
Date Completion: October 2017
Last Updated: May 24, 2017
Last Verified: May 2017