Light-deprivation Utilized to Mitigate Amblyopia
| Status: | Recruiting |
|---|---|
| Conditions: | Ocular |
| Therapuetic Areas: | Ophthalmology |
| Healthy: | No |
| Age Range: | 18 - Any |
| Updated: | 4/21/2016 |
| Start Date: | October 2015 |
| End Date: | October 2017 |
| Contact: | Morgan Williams |
| Email: | mwilliams@sunyopt.edu |
| Phone: | 212-938-1294 |
Optimized Visual Recovery in Adult Human Amblyopia Through Binocular Deprivation
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.
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.
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 of learning-induced recovery from
amblyopia.
Twenty-four adult amblyopes, age 18 or older, will be recruited for the study. The
investigators will exclude amblyopes with strabismus history because the treatment has not
been designed to improve binocular alignment (motor fusion). Thus, amblyopes will be form
deprivation amblyopes, especially form deprivation due to anisometropia, with moderate
(20/30 to 20/80) or severe (20/100 to 20/400) acuity in the affected eye. Screening will
include an extensive application, telephone interview of two personal references,
comprehensive visual examination, and in-person interview.
Participants will be fitted with new ophthalmics if indicated and followed for several weeks
to allow their amblyopia to stabilize. Their visual function will be assessed behaviorally
and also by direct measurement of neural activity using visually evoked potentials (VEPs).
Participants will be assigned to one of three groups. One group will be sequestered for zero
days, one for five continuous days, and one for ten continuous days. Participants in the
five or ten day sequestration groups will undergo sequestration in groups of two, three, or
four. After sequestration visual function will again be assessed, both behaviorally and with
VEP. All participants will then undergo 8 weeks (3 weeks before, 5 weeks after) of vision
treatment for amblyopia, based on video game play. Vision testing will occur regularly
during this period and for 10 months thereafter. A third VEP scan will be done at the end of
the 8 week treatment period.
If successful, this work would transform therapy for adult amblyopia, and focus attention on
the importance of incorporating methods to enhance synaptic plasticity as an adjunct to
treatment. In addition, the insight gained from this work could be extended to strabismus,
eye movement control disorders, and the restoration of optimal neural function after damage
from stroke or other traumatic brain injury. The proposed experiment will also pioneer the
use of binocular visual deprivation in human amblyopes, and develop standards for
implementation, participant sequestration and care.
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 of learning-induced recovery from
amblyopia.
Twenty-four adult amblyopes, age 18 or older, will be recruited for the study. The
investigators will exclude amblyopes with strabismus history because the treatment has not
been designed to improve binocular alignment (motor fusion). Thus, amblyopes will be form
deprivation amblyopes, especially form deprivation due to anisometropia, with moderate
(20/30 to 20/80) or severe (20/100 to 20/400) acuity in the affected eye. Screening will
include an extensive application, telephone interview of two personal references,
comprehensive visual examination, and in-person interview.
Participants will be fitted with new ophthalmics if indicated and followed for several weeks
to allow their amblyopia to stabilize. Their visual function will be assessed behaviorally
and also by direct measurement of neural activity using visually evoked potentials (VEPs).
Participants will be assigned to one of three groups. One group will be sequestered for zero
days, one for five continuous days, and one for ten continuous days. Participants in the
five or ten day sequestration groups will undergo sequestration in groups of two, three, or
four. After sequestration visual function will again be assessed, both behaviorally and with
VEP. All participants will then undergo 8 weeks (3 weeks before, 5 weeks after) of vision
treatment for amblyopia, based on video game play. Vision testing will occur regularly
during this period and for 10 months thereafter. A third VEP scan will be done at the end of
the 8 week treatment period.
If successful, this work would transform therapy for adult amblyopia, and focus attention on
the importance of incorporating methods to enhance synaptic plasticity as an adjunct to
treatment. In addition, the insight gained from this work could be extended to strabismus,
eye movement control disorders, and the restoration of optimal neural function after damage
from stroke or other traumatic brain injury. The proposed experiment will also pioneer the
use of binocular visual deprivation in human amblyopes, and develop standards for
implementation, participant sequestration and care.
Inclusion Criteria:
- Adults age 18 or older
- Moderate (20/30 to 20/80) to severe (20/100 to 20/400) amblyopia with a visual acuity
of 20/25 or better in the fellow eye
- Must live in or be commutable to the New York Metropolitan area
Exclusion Criteria:
- individuals with study-relevant phobias, anxiety disorders or other mental health
disorders will be excluded, as will people taking anti-depressant or anti-anxiety
drugs
- Must pass all stages of application process:
- Review of full application
- Phone interview
- Telephone interview of two personal references
- On-site eligibility screening evaluation
- On-site complete ophthalmic evaluation
- Criminal background check
- On-site personal interview
- Psychological exam
- Physical exam
We found this trial at
1
site
New York, New York 10036
Phone: 212-938-1294
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