Sensor-Equipped Contact Lens Monitors Glaucoma Symptoms Around the Clock

A circular strain gauge in the contact lens detects changes in the diameter of the eye. The tiny microelectromechanical systems chip then reads the data and transmits the information wirelessly to an external receiver worn around the patient's neck. Sensimed

Glaucoma is a tricky ailment to manage; rather than being a single disease, it’s actually a cluster of diseases with various manifestations that, taken as a whole, are the second leading cause of blindness. But medical microtechnology firm Sensimed has engineered a sensor-laden contact lens that glaucoma sufferers can wear around-the-clock, helping doctors not only manage the potentially debilitating disease, but also learn more about how the mysterious condition works.

Little is really understood about glaucoma’s mechanisms, mostly because they are constantly changing. For instance, one manageable symptom that seems to be linked to the disease’s progression is high intraocular pressure, or pressure caused by too much liquid inside the eye. But intraocular pressure changes throughout the day, usually peaking at night when patients are not under doctor’s observation. Snapshots of the condition taken during routine doctor visits provide little insight into how the symptoms and diseases are evolving.

Sensimed’s Triggerfish system is a wearable silicon hydrogel contact lens full of embedded sensors and a microprocessor that can wirelessly transmit data to a receiver worn around the patient’s neck. A strain gauge can detect when pressure in the eye causes the diameter of the cornea to change. By tracking when, how often and how drastic intraocular pressure changes in a patient’s eye, doctors can better tailor medication regimens to make patients more comfortable and make determinations concerning the viability of other treatment options like surgery.

But while Triggerfish offers doctors and patients a better monitoring tool with which to manage individual cases of glaucoma, it could have a much greater impact as a diagnostic tool and data generator. Previously, the only means to gather a 24-hour-a-day picture of how glaucoma really works was an overnight stay at the hospital. A contact lens that measures glaucoma in action around the clock could provide researchers with the data and insight they need to finally understand, and eventually cure, the disease.

Technology Review