Finger pricks, blood draws, and urine testing are miserable for just about everyone. But now researchers are working on a new concept to make testing for disease much easier. The project? A contact lens that would use the condition of the eyes to help spot illness.
If Your Tears Could Talk
It turns out that a doctor can determine a lot about the state of your health just by looking into your eyes. Those baby blues can indicate signs of coronary artery disease and help people with diabetes keep tabs on their blood sugar. Eye problems are even associated with some brain tumors.
The fluid in teardrops can be telling, too. “There is a fair amount of information that can be monitored in a teardrop,” lead researcher Gregory S. Herman, Ph.D., of Oregon State University, told Gizmodo. “Of course, there is glucose, but also lactate (sepsis, liver disease), dopamine (glaucoma), urea (renal function), and proteins (cancers).”
Doctors in all specialties struggle with how to get patients to follow their recommendations, from heart patients taking all of their medication as prescribed to diabetics completing continuous blood sugar tests. Herman and his team thought a daily disposable contact lens could be the key to removing barriers for patient use: it’s easy, it’s not painful and it’s not visible to anyone else. The researchers presented their prototype lens in April 2017 at a meeting of the American Chemical Society.
The First Step: Glucose
It’s long been known that people with diabetes have higher glucose levels their tears, urine, and blood. In this study, researchers used the same kind of technology that’s enhancing smartphone displays—a compound called indium gallium zinc oxide (IGZO)—to make the glucose-sensing contact lens. The sensors that will be embedded into the contact lenses have an enzyme that oxidizes glucose from the tears, causing a shift in pH levels. That pH shift then changes the electrical current, and the sensors measure this change to determine glucose concentrations. Still, testing tears is tricky stuff. The sensors have to be more sensitive than they would if they were testing blood or urine.
The new developments could mean big things for people with diabetes, along with other issues. “The sensor could communicate with your phone to warn you if your glucose was high or low,” Herman said in a media release. The scientists hope to expand the capability to detect other conditions, even early detection of cancer, and have begun using their system to measure uric acid, a signal of kidney function. Theoretically, more than 2,500 bio-sensors could fit into just one millimeter of a contact lens, according to Herman. However, Herman says it’s unlikely contact lenses will eventually make all blood testing irrelevant. Researchers say animal testing of the lens, which would precede human testing, won’t happen for at least a year.