No More Eye
Charts?
From a news story by
CNN San Francisco Reporter Don Knapp
March 1, 2000
It’s not what Thomas McKay sees in this machine, but what the machine
sees in him that determines how well his eyes view the world. McKay
is demonstrating a prototype device that sends a hundred thousand beams
of light into his eye to measure the focusing accuracy of his eye's
lens.
Professor Josef Bille is the inventor of the device, "As those
beams travel into the eye, they're reflected off the retina, and as
they come back they are bent a little bit according to the refracted
abnormalities inside the eye."
By calculating how accurately
the eye's lens bends the light, the prototype Visx machine can determine
how much correction the eye needs to see normally -- without a patient
ever looking at an eye chart.
The doctor checks a patient,
"And we can see you have a half diopter sphere, a half diopter
cyl, about 77, overall through most of your eye you're seeing quite
well."
It's called wave front technology. Physics professor Josef Bille
pioneered it at the University of Heidelberg in Germany, twenty-five
years ago, as a way to counter atmospheric distortion in telescopic
images.
Dr. Stephen McLeod of the University Of California San Francisco checks
a patient the old way with eye charts, "Number one, number two?"
"Number one is better..." "Good."
But University of California
ophthalmologist Dr. Stephen McLeod says, "Human vision is more
complex than how well our eyes bend light. The interaction of the focusing
elements of the eye with the retina, and the interaction of those elements
with higher processing systems in the brain, that it would be an oversimplification
to simply look at the optical system of the eye and say well now we
have the best correction."
McLeod says he considers Visx wave front technology a useful tool but
he says he isn't yet ready to throw away
His eye charts.
Additional notes:
The word Visx refers to laser vision correction or laser eye
surgery. It is a brand name with a promotional site at http://www.visx.com.
Twenty-five years later, Josef Bille is still an inventor in Germany.
He has recently invented lenses that will cost about one dollar a pair
and should be on the market soon. It is possible that his designs will
allow people to see at night. These night vision lenses will enable
people over the age of 50 to see as much as five times better at night.
Bille is also designing special vision devices for people in professions
where perfect sight is a must.
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