team up for vision research
to the brain
23, 2000, Gazette)
Its impossible for six-month-old
Jagger to read a standard eye chart but researchers at MUN have
devised a new test that should permit accurate measurement/diagnosis
of vision in the critical first few years of life.
around and it seems like half of the people you see are wearing
glasses these days, not to mention contact lenses. More and more
people are availing of a new laser surgery technique to correct
their vision problems and cataract surgery is no more painful
than getting a tooth filled. It certainly seems that at the rate
medical technology is going, it will only be a matter of time
before everyone will be able to claim 20/20 at the DMV.
again, warn Drs. Russell Adams and Mary Courage, Psychology.
dont often realize that its not just the eyes that
control vision, but also certain visual areas of the brain. Problems
cant always be fixed at the eye level, said Dr. Adams.
Vision problems, particularly in children, are often brain
problems. Its important to catch vision problems early
because permanent changes to the cells of the brain simply isnt
possible after five or six years of age.
is highly organized in the nervous system with different routes
laid out for different types of stimulation, he explained.
while we know what these routes are and where they are in adults
and animals, we have yet to understand when they develop in human
beings, specifically during the first few years of life.
researchers in infant vision studies, Drs. Adams and Courage
seek to understand the ways in which brain function is modified
by early visual experience in both normally and abnormally developing
infants. To determine how parts of the brain and eye develop
together, Dr. Adams along with Avery Earl, a computer consultant
in Psychology, developed a new and comprehensive test that looks
at pattern recognition in infants.
a contrast sensitivity test, Dr. Adams presents his test subjects,
children ranging from 10 week premature to three years of age,
with a series of large cards comprised of striped circles of
varying contrasts. A subjects fixation on one of the circles
indicates that the subject has developed a pathway sensitive
to that particular level of contrast.
sensitivity is itself one of the most sensitive measures of human
vision, he said. It is the best single test for telling
us about visual and neurological processes. But most importantly,
it allows you to make an educated guess at where problems may
lie, whether its in the eye or in the brain.
contrast sensitivity test will help us to develop new tests for
diagnosis down the road and if these tests help us to scan for
possible vision problems, thats great. Thats our
hope, that we could start testing early with the best technology
Adams, with the help of PhD candidate Jamie Drover, has already
developed and published a growth chart based on the data collected
from normally developing infants and children.
weve found thus far we tried to apply to kids we suspect
are at risk for poor vision or poor neurological development
such as very premature babies and children with Down Syndrome.
project that the team is working on seeks to better understand
visual information processes and how they relate to early memory
retention. This may have implications for the early detection
of cognitive delay.
aspect of the research utilizes two tests the Fagan Test
and the Paired Comparison Procedure to measure the amount
of time visual information is retained in the brain. In each
experiment the subject is exposed to a pair of similar visual
stimuli. Over pre-determined periods, one of the stimuli is changed
the baby fixates on the altered stimulus, explained Dr.
Courage. We know that babies prefer the new over the familiar
and patterns over the plain. What were looking for are
differences in the way they recognize patterns. For example,
we look at whether they are what we call short-lookers or long-lookers.
other words, how long it takes for them to notice a change in
the pattern. This reflects the speed at which they are processing
Courage warns that speed in processing may not necessarily be
an indication of intelligence.
Courage hopes that the data she is collecting will one day help
to in the early diagnosis of General Developmental Delay or more
specific problems such as Attention Deficit Hyperactivity Disorder.
Adams and Dr. Courage are also collaborating with Dr. James Friel,
Biochemistry. Dr. Friel is investigating antioxidants and nutrition
as ways to combat brain disorders, including vision problems,
caused by oxygen deprivation and respiratory diseases in very
premature infants. All three are working closely with neonatologists
Dr. Khalid Aziz and Dr. Wayne Andrews of the Janeway Childrens
infant vision research currently being conducted by Drs. Adams
and Courage boasts the highest number of newborns tested in the
world. It also boasts regular support in the form of funds provided
by the Natural Science and Engineering council of Canada (NSERC),
the Medical Research Council (MRC), and the Janeway Foundation.
Students Promoting Awareness about Research Knowledge, is a NSERC
funded program designed to encourage writing about research.