Vision for the Future: Smart Contact Lenses

Researchers are working to develop and fabricate soft, smart contact lenses by combining recent advances in wearable electronics with wireless communications. Their vision is to create a smart contact lens which is capable of monitoring the physiological information of the eye and tear fluid, to provide real-time, non-invasive medical diagnostics.

Previous Technology and Challenges to Overcome

Several early attempts to manufacture smart contact lenses resulted in less than optimal products. The previous reports indicated that opaque and brittle components were used to enable the operation of the electronic device, which could also block the user's vision and potentially cause damage to the eyes.

Some of the crucial issues to be addressed before practical uses of smart contact lenses can be realized include:

• The use of opaque electronic materials for sensors, integrated circuit (IC) chips, metal antennas, and interconnects that can block the user's vision.
• The integration of the components of the electronic device on flat and plastic substrates, resulting in buckled deformations when transformed to the curved shape for lenses, which in turn creates foreign objects that can irritate the user's eyes and eyelids.
• The rigid and brittle materials of the integrated electronic system, such as surface-mounted IC chips, which could damage the cornea or eyelid.
• The requirement for expensive and bulky equipment for signal measurements, which limits the use of smart contact lenses outside of the clinical or laboratory setting by restricting the user's external activities.

A New Design for Soft, Smart Contact Lenses

In their article, "Soft, smart contact lenses with integrations of wireless circuits, glucose sensors, and displays," authors Jihun Park, Joohee Kim, So-Yun Kim, and colleagues, propose an unconventional approach to overcome the challenges mentioned above. They envision combining stretchable and skin-like electronics with wireless communications to enable noninvasive and comfortable physiological measurements. They used three strategies to define their goals:

• Transparency  The wearer's view would not be obstructed because the contact lenses are made of transparent nanomaterials.
• Reliability  The planar, mesh-like structures of the components of the device and their interconnects enable high stretchability for the soft curved lens with no buckling.
• Real-time results Display pixels integrated into the smart contact lens allow access to real-time sensing data that eliminates the need for additional measurement equipment.

Their ultimate aim is to develop a method to fabricate a soft, smart contact lens that can monitor glucose levels in human tears to indicate the diabetic condition in real time through a display with wireless operations.

Based on their three-pronged strategy they integrated the electronic components (the glucose sensor, LED pixel, rectifier circuit, and the stretchable, transparent antenna) onto a mechanical stress-tunable hybrid substrate with well-matched indices for high optical transparency and low haze.

Medical Applications for Smart Contact Lenses

Other researchers are simultaneously studying future applications and the manufacture of smart contact lenses for specific medical monitoring.

Glaucoma

Columbia University Irving Medical Center researchers are working to develop smart contact lenses that can monitor and tell how quickly a patient's glaucoma is progressing. Glaucoma damages the optic nerve and causes vision loss or even blindness. 

In a clinical study, 40 glaucoma patients wore smart contact lenses that measured fluctuations in eye pressure via sensors that detected changes in the curvature of the eye.  A wireless device sent readouts to an ophthalmologist. As the pressure inside the eye is the only risk factor that is controllable, doctors expect to be better able to monitor a patient's symptoms and treat them more effectively.

Diabetes

The researchers mentioned above are not the first or only ones to join the race to find a working model for a smart contact lens that measures glucose levels in diabetic patients. 

Harry Gandhi is an entrepreneur whose goal is to create a smart contact lens that can detect glucose in a patient's tears and transmit the data via an antenna to a small device that attaches to a collar, necklace, or glasses. That device then sends the information to a Bluetooth-enabled gadget like a smartphone so that an app can store and analyze the data. His team also seeks to differentiate the monitoring needs of either type 1 or type 2 diabetic patients, along with building their own app to manage the data.

Conclusion

Tech journalists predict that many new ideas for electronic smart contact lenses will continue to be inspired thanks to the ever-shrinking size of electronics. They even propose smart contact lenses working in tandem with another wearable, including hearing computing devices, giving us most of the benefits of smartphones and smartwatches without any visible electronic gadget.