JAMA Ophthalmology Journal Club Slides:
Vision Restoration Training for Glaucoma
Sabel BA, Gudlin J. Vision restoration training for glaucoma: a
randomized clinical trial. JAMA Ophthalmol. Published online
February 6, 2014. doi:10.1001/jamaophthalmol.2013.7963.
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Introduction
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Vision loss in glaucoma was considered irreversible.
However, the brain, which processes vision, is modifiable
even in adulthood and old age, able to adapt to change.
Evidence for this neuroplasticity includes the following:
• In adult visual cortex, receptive fields can change in
size and location after retinal injury.
• Training eccentric (peripheral) viewing in macular
degeneration activates cortical regions normally
representing central visual areas.
• Visual training can improve visual fields in
hemianopia, optic nerve damage, and amblyopia.
• Noninvasive transorbital alternating current
stimulation can improve visual fields in optic
neuropathy.
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Introduction
• Motivation to initiate study: pilot trial results showing that vision restoration
training for glaucoma (gVRT) improved detection accuracy in 4 of 5 patients
with glaucoma.
Before
After 3 months of gVRT
Pilot study patient, age 56 years, chronic open-angle glaucoma, right eye
• Study Objective: To evaluate efficacy of gVRT.
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3
Methods
Study Design
• Prospective, double-blind, randomized, placebo-controlled clinical trial.
• Blinding procedure: neither the patient nor the outcome assessor was
aware of the patient’s group identity.
Intervention
• Computer-based vision training with gVRT designed to preferentially
present visual stimuli in areas of residual vision (ARVs) to activate them
(n=15) or
• Visual discrimination placebo training where visual stimuli are presented
only in the intact visual field (n=15).
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Training in both groups lasted 6 days a week for 3 months (for 30 min twice
daily) on a home PC with adaptive parameter adjustments online.
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Hemianopia visual field
ARVs: Shades of Gray
5
Fully input
Full damage
Partial damage
Glaucoma visual field
Vision intact
ARV
Blind
The extent of vision loss (detection ability) is a
function of neuronal loss: the greater the cell loss
is, the greater the field defect in different regions of
the visual field. ARVs can be found in all kinds of
visual field defects such as after stroke
(hemianopia) or retinal damage (glaucoma).
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Sabel et al., Progr Brain Res, 2011
Methods
Data Analysis
• Statistical comparisons: pretreatment vs posttreatment within and between
groups.
• Primary outcome measure:
– Detection accuracy in high-resolution perimetry (HRP) visual fields.
• Secondary outcome measures:
– White-on-white and blue-on-yellow near-threshold perimetry.
– Reaction time in HRP.
– Eye movement (eye tracker), fixation reliability.
– Vision-related quality of life as assessed with the 25-Item National Eye
Institute Visual Function Questionnaire (NEI-VFQ-25).
Limitations
• 30-minute training creates fatigue in some patients (pauses required).
• Training discipline needed for 3 months of daily training.
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Results
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Single patient example of HRP detection chart before vs after gVRT.
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Results
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Within-group analysis of detection performance. HRP detection rate in the
gVRT group increased significantly compared with placebo.
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Results
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Comparison of detection accuracy changes.
Between-group analysis: pre-post detection improvements greater with gVRT than
placebo, but results are variable.
Patients, %
Improvement
Detection Rate Change, %
33.3
No change
<3
26.7
Moderate
3-10
40.0
Large
>10
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Results
Further Observations
• HRP reaction time was significantly faster after gVRT than after placebo.
• Visual improvements were located mainly in ARVs.
Vision-Related Quality of Life Measured by NEI-VFQ-25
• The gVRT group but not the placebo group significantly improved on the
mental health subscale and reported subjective visual improvements due to
training.
• Both groups reported a high level of satisfaction with the vision training, which
confirms successful blinding on the group identities.
Eye Movements and Fixation Performance
• No change in either group.
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Comment
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Compared with placebo, gVRT significantly improves vision in glaucoma in
the following:
– Detection accuracy in HRP and in white-on-white and blue-on-yellow
near-threshold perimetry.
– Faster reaction times compared with placebo.
– Improved general health and subjective training effects.
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Changes cannot be explained by natural fluctuations or eye movements.
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Results confirm the following:
– Previous pilot study in glaucoma.
– Controlled trials of vision restoration training in hemianopia and optic
nerve damage.
– Variability of response in prior studies:
• Approximately one-third were nonresponders, one-third had
moderate response, and one-third were substantial responders.
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Comment
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Possible mechanism(s) why gVRT works:
– Plasticity in the retina.
– Changes of receptive fields at higher processing levels (lateral
geniculate or visual cortex).
– Improved visual attention.
– Enhance synchronization of brain wave activity.
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However, further studies are needed using electroencephalography or
magnetic resonance imaging to clarify mechanisms.
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Comment
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General take-home messages:
– Visual system neuroplasticity is maintained into adulthood and even old
age, despite widespread visual system degeneration.
– Vision loss in glaucoma must not be permanent; it is partially
reversible.
– Vision restoration is subjectively notable and clinically useful.
– The findings confirm the theory of activating residual vision after retinal
or brain damage through brain plasticity (Sabel BA, Henrich-Noack P,
Fedorov A, Gall C. Vision restoration after brain and retina damage: the
“residual vision activation theory.” Prog Brain Res. 2011;192:199-262).
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Contact Information
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If you have questions, please contact the corresponding author:
– Bernhard A. Sabel, PhD, Institute of Medical Psychology, Medical
Faculty, Otto-von-Guericke University of Magdeburg, Leipziger Strasse
44, 39120 Magdeburg, Germany (imp@med.ovgu.de).
Funding/Support
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This work was supported by NovaVision Inc (Dr Sabel), by Braingames
Online GmbH (Dr Sabel), and by a predoctoral fellowship under the LOM
program of the University of Magdeburg (Dr Gudlin).
Conflict of Interest Disclosures
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None reported.
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