Health tech overstatement of the day: ‘a contact lens that tells you when you’re sick’

click to enlargeThis Editor likes Gizmodo, and doesn’t want to seem overly cynical or critical, but here we go again with an article that gives the impression that biosensing contact lenses are just around the corner. Our Readers will recall Google’s much hyped glucose-sensing lens developed with Novartis/Alcon dating back to 2014 [TTA 27 Mar 15]. This research is out of Oregon State University and is testing a transparent biosensor which will detect glucose levels in tears. The biosensor contains a transparent sheet of IGZO (gallium zinc oxide) transistors and glucose oxidase, an enzyme that breaks down glucose. In breaking down the glucose, it causes the pH level to shift and generate a measurable change in the electrical current going through the IGZO transistors. The researchers project that 2,500 of these transistors could be embedded in the lens, enabling multiple sensors detecting multiple chemicals which could lead to disease detection.

Why raise the yellow flag? If the lenses are to be used for continuous monitoring or even short term, thick lenses (like the old hard plastic or gas-permeable) require a period of wear-in to get the cornea habituated to it, and even after, there is the hazard of corneal abrasion. Irritation is especially hazardous for diabetics, who have a greater likelihood of eye injury and also related vision problems. Animal testing of the current version is over a year away. They don’t yet have a way to power the lens sensors. Contact lenses with sensors for various problems (e.g. Sensimed’s lens for glaucoma intra-ocular pressure) and Samsung’s Gear Blink embedded camera have been prototyped for years and none have made it into commercial release. Cost is a major unanswered question. While the researchers are to be applauded for the approach and applying it to other chemicals detectable in the eye, disease-sensing contact lenses will take years to be commercially available, if ever, and the article largely makes them seem just around the corner. Thin films applied to the skin for vital signs monitoring seem so much more…wearable [TTA 3 Feb]. Research to be presented at the American Chemical Society‘s annual meeting today (4 April). Photo is artist’s depiction of lens, courtesy of OSU

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