Some
say the eyes are the window to the soul, but an Australian medical
researcher says they are the window to the heart and beyond.
Tien
Wong of the Center for Eye Research Australia at the University of
Melbourne has shown in several large-scale studies that abnormalities
of the blood vessels in the retina can be used to predict patients'
risk for diabetes, hypertension (or high blood pressure), stroke and heart disease.
These four disorders are some of the most common causes of death, hospitalization and disability in the developed world. But the ability to predict them is limited.
In plain sight
The retina
is a membrane that surrounds the eyeball and receives light from the
lens and converts it into signals that reach the brain and result in
vision [Graphic: The Eye].
Wong's
approach involves analyzing digital photographs of patients' retinas
and studying them to find narrowing or ballooning of the small blood
vessels. Systemic diseases—those that affect several organs or the
whole body—such as hypertension, diabetes, AIDS, Graves' disease,
lupus, atherosclerosis, multiple sclerosis, rheumatoid arthritis, and
sickle cell anemia often cause changes in the eye that can show up as
red dots or small blood clots.
Blood
vessels of the eyes are so predictive because they are part of the
brain's vascular system, so they share anatomical features and respond
similarly to stress and disease, Wong said.
In
fact, eyes are so transparent compared to the rest of the body that
they are the only organ that allows physicians to directly see blood
vessels. The digital photography approach is non-invasive—no blood is
taken, no incisions are made, no probes in orifices. It takes just a
few seconds.
Wong
has shown that retinal abnormalities are a good predictor of whether a
patient will develop high blood pressure or die of cardiac disease in
the next 10 years.
"My
hope is that one day, retinal imaging will be able to provide an
additional means to stratify risk and help identify people who may
benefit from early lifestyle changes and preventive therapies,” Wong
told LiveScience.
Eyes on the Internet
The
idea that the eye is a window to the human body has been around for
more than a century, but Wong has figured out how to make precise and
quantifiable predictions for illness based on retinal abnormalities
that can be used as a standard by all doctors.
Wong
sees a future in which physicians include retinal data in making
treatment decisions. First, they'll need to arrive at a common
classification system for diagnosing retinal abnormalities.
Ultimately,
Wong and his colleagues, who now are setting up a Retinal Vascular
Imaging Center in Melbourne, plan to develop a Web-based system to
which doctors can upload digital images of patients' retinas. The
system will report back the extent of a patient's cardiovascular
disease.
It remains to be seen, though, how useful the system will be and with how many diseases it may prove helpful.
Emily
Chew, a medical researcher at the National Eye Institute in Bethesda,
said she was not surprised by Wong's findings relating retinopathy with
diabetes.
"It is
important for all persons with diabetes to have regular eye exams
(annually) and for those over 65 to have eye exams on a yearly basis to
detect any eye disease that maybe treatable, Chew said in an email
interview.
However,
Chew said eye exams will pick up only a small percentage of the
population that have other systemic diseases and "one would not screen
with eye exams for systemic diseases.”
| 
