different methods. 1. Technology
using magnetic pulses. 2. Low voltage
currents, commonly used in neurology
for depression and stroke-related
vision loss, by applying mild electric
charges over parts of the brain.
The magnetic pulse treatments conducted with a small group of people
showed temporary improvement in
their conditions for 24 hours, which
Thompson said provided confidence
the visual cortex of the brain was an
area that showed promise for focused
treatment.
To confirm this, the studies also
included a placebo test, which in one
case saw a patient receive the normal
current delivered to evoke a response
for about 30 seconds, while gradually
decreasing the voltage. In another, a
current was delivered to give the patient the sensation of the treatment,
but not enough to induce change in
the visual cortex.
Working with a larger group of people
alongside Sun Yat-sen University in
China, the studies have shown “quite
promising results” including improved
visual and contrast response from
the brain.
Thompson is actively pursuing funding
for a large-scale randomized clinical
trial, which would take two years to
develop and two additional years of
trials. The goal would be to establish
treatments for mainstream use with
adult patients, and create a model for
the treatment to help enhance plasticity and aid in the recovery other
brain-based visual loss cases.
“I have confidence we're taking a big
step forward,” he said.
The data gained by Thompson led him
to the most recent Transcranial Direct
Current Stimulation (TDCS) studies,
which are portable and both safe and
low risk for patients, he said. The
results and the visual response of the
electric current tests were beneficial,
but temporary – about 30 minutes for
the patient, but the rebalancing of the
patient's vision provided baseline
data and reasoning to continue studies,
Thompson said.
The currents create a slight tingling
sensation on the scalp, and are only
done with adults, in this case aged 17
and older. The exploratory studies have
shown evidence that currents can inhibit or suppress the areas of the brain
responsible for the abnormalities that
cause the condition.
This data is recorded using a Visually
Evoked Potential (VEP) device, which
measures activity within the brain's
vision centre to ensure actual response
and benefit can be noted, he said.
“We use brain imaging to understand
the stimulation,” he said, noting optometry has an advantage over other
fields because of the ability to
“incredibly precisely” measure visual
function for response.
Optical Prism | October 2016 35