New Contact Lens May Measure Glucose
By JUDY LIN
PITTSBURGH (AP) — What if checking a person’s blood sugar level were as easy as looking in the mirror?
The idea may become reality as researchers at the University of Pittsburgh work on a contact lens that measures glucose levels. They are trying to create a contact lens that will contain a chemical sensor at the edge of the lens which can be worn by everyone, even those who don’t need vision correction.
“If this all works, this should revolutionize monitoring of glucose by patients,” said Pitt chemistry professor Sanford Asher, who developed the sensor that can detect glucose in human tears.
For years, the medical community has been trying to find painless ways for diabetes patients to monitor their blood sugar levels. With an estimated 17 million Americans suffering from the disease, millions must endure painful finger testing by pricking themselves several times daily. Doctors often complain that even the most diligent patients don’t test themselves enough.
Diabetes costs the nation about $91.8 billion annually, including $23.2 billion in direct medical costs, according to the American Diabetes Association. The ongoing search for painless monitoring devices has brought about contraptions such as GlucoWatch, which looks like a wristwatch and uses tiny electric currents to monitor blood sugar.
CIBA Vision also is working on a daily contact lens that would be able to detect glucose levels, said company spokeswoman Kristie Madara. The concept involves flashing a light over the wearer’s eye; the lens would change color depending on the person’s blood sugar level.
“We’ve done a small study measuring whether you can measure glucose in the tear film. It’s now in the early developmental phase,” Madara said.
It could be years before the lens is out on the market.
Doctors say they are intrigued with such lenses because with so many patients citing finger testing among their top hassles, there’s a big market for noninvasive products. However, they suspect people who have diabetes and wear contact lenses may take to such products faster than diabetics who aren’t used to lenses.
“Obviously it’ll take time and we need to see the results and how they compare to traditional ways of testing, but the need for it is clearly there,” said Dr. Nathaniel Clark, national vice president for clinical affairs at the ADA. “We think it’s very interesting.”
Richard Calderon, associate chief of the Beetham Eye Institute at Joslin Diabetes Center in Boston, said the institute is in the middle of conducting clinical tests on the lens for Duluth, Ga.-based CIBA. Preliminary results show diabetics can wear the type of lens CIBA wants to use for the glucose lens with the same comfort as people without diabetes, Calderon said.
“Everybody’s looking for the best way people can test their blood sugar and monitor glucose levels by the least invasive method,” Calderon said. “It’s also not only the best way, but a comfortable way.”
The contact lens being developed at Pitt is at least three years away from being available on the market.
For their lens, Asher and pediatrics professor David Finegold plan to embed their patented sensor into contact lenses. Patients will be able to determine their glucose levels by looking in a mirror and comparing the color of the sensing material to a chart.
Gradations have yet to be determined, but green is for normal, red for extremely low glucose and violet for extremely high glucose.
“You can dramatically improve control of glucose, either using insulin, oral hypoglycemic agents or exercise. But you have to know glucose levels,” Finegold said.
Asher said his team of researchers have already developed the sensor material for the lens, secured the patent on the technology and have investors lined up for a startup company.
A study on the sensor material will be published May 1 in Analytical Chemistry, a publication of the American Chemical Society.
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