Press Release

Major technical advance in astronomy improves diagnosis of eye diseases

By SpaceRef Editor

January 21, 2003

Filed under Indiana University, Space Physiology and Medicine, US

BLOOMINGTON, Ind. — A major technical advance in astronomy
is making it possible for scientists to see individual
living cells of the human retina clearly for the first time.
This will greatly improve doctors’ ability to diagnose
diseases of the retina such as glaucoma at an early stage,
when intervention and treatment can prevent blindness.

A technology called adaptive optics allows astronomers to
see distant stars with the ground-based Keck Telescopes in
Hawaii almost as well as with the Hubble Space Telescope.
Adaptive optics is a computerized system that continually
measures optical flaws and then automatically corrects for
them. It eliminates the distorting effects of Earth’s
turbulent atmosphere when astronomers are viewing objects
in space with the Keck Telescopes.

Donald T. Miller and Larry Thibos, professors in the
Visual Sciences Group at the Indiana University School of
Optometry in Bloomington, are applying adaptive optics to
the problem of eliminating the distorting effects of a
patient’s eye so they can examine the living cells of the
retina at the back of the person’s eye. Their high-quality
instruments for examining the retina correspond to the
astronomer’s telescope; the cells of the retina correspond
to stars in space; and the patient’s eye corresponds to
Earth’s atmosphere since it is constantly changing,
preventing images of the retina from becoming clearly
focused for the examiner.

"The eye is a mediocre optical instrument compared with
the tools that ophthalmologists and scientists have
available," Thibos explained. "The eye is inferior
because it is made out of biological materials, it grows,
it is constantly changing and controlling its own growth,
it has numerous flaws, and it gets worse as the person
gets older."

Thibos has devised an instrument called an ocular
aberrometer that measures optical aberrations in the eye
by sensing errors in optical wavefronts reflected from
the retina. Miller has developed technology that
corrects those errors to obtain high-resolution images
of the retina. "That’s where the state of the art is
right now," Thibos said.

Though their combined instrumentation is not yet in
clinical practice, "It looks like there will be a large
explosion of this in the next few years," Miller said.
"Right now there are about five operational sytems in
the world in laboratories, including here at IU."

When the equipment becomes available for clinics, a doctor
will be able to get a clear view of individual cells in
the retina and determine whether the cells are healthy or
diseased, instead of having to wait for visible symptoms
of retinal disease to appear. By the time symptoms become
apparent, retinal cells often are dead and blindness may
be unavoidable. If signs of retinal cell disease can be
detected early, there is a much better chance of saving
the patient’s vision.

"In glaucoma, for example, the actual disease is cells in
the optic nerve dying, and right now doctors can’t see
that happening," Thibos said. "They can only see it after
the cells are dead. It may take 10 years for changes in
vision caused by glaucoma to show up. They could do much
better in treating glaucoma if diagnosis were early."

Age-related macular degeneration is another major
application for this technology. "Scientists can now see
retinal cells degenerating in the laboratory, but not in
the patient’s eye," Thibos said. "Early diagnosis would
allow much superior treatment and prevention of blindness."

For more information, contact Thibos at 812-855-9842 or
thibos@indiana.edu and Miller at 812-855-7613 or
dtmiller@indiana.edu. Their research is funded by the
National Eye Institute of the National Institutes of
Health and by the National Science Foundation Center for
Adaptive Optics.