“Smart” Contact Lens Promises To Detect Glaucoma Earlier
STMicroelectronics will develop and supply a wireless MEMS sensor that acts as a transducer, antenna and mechanical support for additional read-out electronics in a breakthrough platform developed by Swiss company Sensimed AG. This solution will enable better management of glaucoma patients via earlier diagnosis and treatment that is optimally tailored to the individual patient.
Known as the SENSIMED Triggerfish®, the solution is based on a “smart” contact lens that uses a tiny embedded strain gauge to monitor the curvature of the eye over a period of, typically, 24 hours, providing valuable disease management data that is not currently obtainable using conventional ophthalmic equipment.
Glaucoma(3), the second most common cause of blindness around the world, is an irreversible progressive disease of the optic nerve that can eventually lead to blindness. Â Although it cannot be cured, its progress can be controlled once it is diagnosed and treated properly. The standard test is the measurement of intraocular pressure (IOP), using an instrument known as a tonometer, during periodic visits to an ophthalmologist. However, the tonometer may fail to detect an elevated IOP, especially in glaucoma patients, because the pressure varies during the day and often peaks during sleep or outside of office hours. As a result, the disease is often diagnosed only after significant damage to the optic nerve has already occurred, and the disease keeps progressing in many patients due to inadequate treatment.
Sensimed’s ingenious solution is a two-part system comprising the smart contact lens and a small receiver worn around the patient’s neck. Â In addition to the strain gauge the lens contains an antenna, a tiny dedicated processing circuit and an RF transmitter to communicate the measurements to the receiver. The lens is powered via the received radio waves and does not need to be connected to a battery. The embedded components are positioned in the lens in such a way that they do not interfere with the patient’s vision. The lens is fitted by the ophthalmologist and when the patient returns the next day the ophthalmologist removes the lens and receiver, obtaining a complete record of IOP changes over the preceding 24 hours.
The SENSIMED Triggerfish® has obtained the CE mark(4), is currently running numerous application trials, and is commercially available in selected centers.  ”The device is easy to use and has facilitated and improved patient care substantially,” said Dr.Kaweh Mansouri who has been using the Triggerfish at the University Hospital, Geneva, Switzerland.
ST engineers are now working with Sensimed to translate this breakthrough technology into a reliable commercial MEMS product ready for mass production. ST expects the development of the MEMS sensor to be completed in Q2 2010 and manufacturing to start in Q3 2010, with availability outside trials to doctors and patients subject to regulatory approvals. Sensimed and ST anticipate progressively rolling out the product country-by-country across Europe beginning in Q3 and entering the US market by the end of 2011.
Nitric Oxide Sensor Provides Up to 10 ppb Accuracy
City Technology has developed a new nitric oxide sensor that provides unparalleled sensitivity, repeatability, stability and speed of response. The NO sensor has been developed specifically for medical applications; in particular, it will supplement existing City products monitoring patients in intensive care and premature babies in neonatal units who are receiving Inhaled Nitric Oxide Therapy to assist with breathing difficulties. It will also be deployed in instruments measuring NO in the breath of patients suffering from Chronic Obstructive Pulmonary Disease, where the sensor’s performance with differing breath conditions obviates the need for large and expensive sample conditioning. It will allow the manufacturers of breath monitoring equipment to develop smaller instruments, making their devices more widely available; for example, they could be installed in doctors’ surgeries where they will enable patients to be given sophisticated tests without, as would previously have been the case, requiring them to attend hospital as an out- or in-patient.
The sophisticated design of the sensor, which does not require the sample of exhaled breath to be adjusted to a particular temperature and pressure to achieve a reliable reading, will enable lower cost instruments to be developed, allowing their use to be extended into an increased number of more mainstream establishments.
The device itself requires only ten seconds exposure to achieve a reliable reading of the NO content of the exhaled breath. It resolves down to 10 parts per billion, at least twenty times better than any other sensor available on the market today. The design of the sensor gives excellent stability in the presence of transient humidity changes, further reducing the complexity required of the instrument; it has a 10 to 30°C operating range and is packaged in the company’s industry-standard compact 7 Series encapsulation. It is rated for more than 2000 exposures and operates on a catalytic, non-consumable principle.
