New
Service for TodaysSeniorsNetwork.com
readers...roll mouse over, click on
highlighted links in stories to review items
from Amazon
Now, keep up to date
with daily feeds of newly posted stories
about America's Seniors...click on the box
to the left
“Fluorescent”
cells give early warning for Eye Disease
Newswise — Scientists
at the University of Michigan have shown
that their new metabolic imaging instrument
can accurately detect eye disease at a very
early stage.
Such a device would be
vision-saving because many severe eye
diseases do not exhibit early warning
signals before they begin to diminish
vision.
The testing is
noninvasive and takes less than six minutes
to administer to a patient.
In a recent study, two
researchers from the U-M Kellogg Eye Center
used the instrument to measure the degree to
which a subtle visual condition affected six
women.
Victor M. Elner, M.D.,
Ph.D., and Howard R. Petty, Ph.D., report
their findings in the February issue of
Archives of Ophthalmology.
The women had been
recently diagnosed with pseudotumor cerebri
(PTC), a condition that mimics a brain tumor
and often causes increased pressure on the
optic nerve that can lead to vision loss.
Because each woman’s
disease was in a very early stage, the
researchers could evaluate how accurately
the instrument would detect vision loss as
compared to several standard tests used to
evaluate vision: visual fields, visual
acuity, and pupillary light response.
In each case the
imaging instrument provided results that
were equal to and often superior to the
standard tests.
The study grew out of Petty and Elner’s
observation that metabolic stress at the
onset of disease causes certain proteins to
become fluorescent.
To measure the
intensity of this flavoprotein
autofluorescence (FA), they designed a
unique imaging system equipped with
state-of-the art cameras, filters, and
electronic switching, together with
customized imaging software and a computer
interface.
Petty, a biophysicist
and expert in imaging, explains why FA data
is a good predictor of disease.
“Autofluorescence
occurs when retinal cells begin to die,
often the first event in diseases like
glaucoma and diabetic retinopathy,” he says.
“Cell death can
be observed microscopically, but not as yet
though any current imaging methods. We
believe this study is a big step forward
toward creating a diagnostic tool that can
characterize disease long before symptoms or
visible signs appear.”
The women in the study
were newly diagnosed with PTC and had not
yet received treatment. According to
standard tests they had good visual acuity,
and their visual field tests indicated
either subtle abnormalities or none at all.
Visual field testing,
used to measure the area seen by the eye, is
a standard tool for evaluating eye diseases
such as glaucoma.
After the standard
vision tests were administered, the
researchers measured FA values for the six
women and the age-matched control group.
All of the patients
with PTC had higher FA values in the eye
that was more severely affected.
In fact, FA values
averaged 60% greater in the more affected
eye of these women. By contrast, the control
group had no significant difference in FA
values between their healthy eyes.
The researchers also
found that FA data more accurately described
the different degree of disease in each eye
for a given patient, as compared to the
standard vision tests.
Elner, who is an
ophthalmologist and a pathologist, says that
the ability to detect subtle distinctions is
important.
“Early treatment for
eye disease is so important, and this study
suggests that FA activity is a very good
indicator of eye disease,” he says.
“Cardiologists
have long used blood pressure testing to
head off heart disease. We believe that FA
testing will likewise be a helpful
diagnostic tool for eye doctors looking to
prevent blindness.”
Elner and Petty have
patented the device through the U-M Office
of Technology Transfer. They are
investigating its use as a screening device
in diabetes and other major eye diseases.
This study was
supported by grants from the National Eye
Institute. Dr. Elner is a Research to
Prevent Blindness Senior Scientific
Investigator.
Reference:
Flavoprotein Autofluorescence Detection of
Early Ocular Dysfunction, Archives of
Ophthalmolgy, 2008:126(2):1-2. Victor M.
Elner, MD, PhD, Seung Park, MD, Wayne
Cornblath, MD, Richard Hackel, BA, Howard R.
Petty, PhD.
...
...
...