Our eyes, our window into the world. Sight, this is the sense that most people say they would not want to live without. We perceive up to 80% of all impressions by means of our sight.
Despite the importance of our vision, nearly 40% of people in the U.S. need glasses and it is estimated that one-third of the world population will be near-sighted by the end of the decade. By 2050, 50% of the world’s population, a total of nearly 5 billion, will be myopic, according to a new review study published yesterday in the journal Opthalmology. As well, farsightedness affects about 5 to 10% of Americans.
We put our eyes through a lot every day. They face dust and dirt, air pollution, rubbing, accidental pokes — and still keep working. How do they do that?
Tears get in your eyes
With tears. Basal tears — the constant, unnoticeable tears that create a thin film over our eyeballs — are full of moisture and nutrients that are essential to keep the eye working. Now researchers believe that tears could help keep more than just the eyes in good health.
A team from Purdue University in Indiana have come up with a novel way of combining contact lenses and sensor tech to help monitor the state of an individual’s blood glucose — a key indicator of how well someone with diabetes is keeping the condition under control.
Purdue University isn’t the first to attempt to crack the smart contact lenses. Microsoft announced its own smart contact lens research back in 2012, while Google followed suit two years later. Both hoped to create contact lenses that could monitor a diabetic’s glucose level through their tears, sparing them the need to do ‘finger-prick tests’. The smart lens can continuously monitor the wearer’s health conditions in a non-invasive manner, simply by wearing the lens.
Chi Hwan Lee, an assistant professor of biomedical engineering and mechanical engineering who led the Purdue team of researchers, became very interested in developing an alternative way to directly construct the sensors on the surface of commercially-available soft contact lenses.
One of the main problems with such diabetic contact lenses is wearability. Creating a smart contact lens means putting rigid, non-see-through components onto a lens that will be in direct contact with the eye. The eye might be clever, but it’s also sensitive: whatever touches it over a long period needs to be gentle enough not to damage the delicate cornea, while not obstructing the vision of the wearer.
Using a new process called interfacial debonding, Lee’s team were able to separate thin-film electronics from their own wafer substrate, and then print them onto another material — in this case, contact lenses. The glucose sensors that are attached to the contact lens are covered by a “thin layer of transparent, biocompatible, and breathable polymer”, according to Lee, meaning the lens won’t irritate the eye or interfere with the normal vision of the wearer.
Add electronics to commercial lenses
Discoveries like Purdue’s have potentially overcome one key obstacle to making smart contact lenses: combining smart electronics with off-the-shelf lenses. Scientists and tech companies working on smart contact lenses for diabetics still have another crucial hurdle to overcome. There are still some questions about how reliably the glucose level in tears translates to the actual glucose level in the blood.
The first challenge is that it is difficult to accurately measure a glucose level from tear films due to the lack of biomarkers and inconsistency from person to person. Many recent investigations aim to address this problem by developing either a high resolution biosensor or platform that can efficiently collect fluids in a reservoir to ensure the measurable biomarkers.
The second challenge is that it is difficult to ensure the biocompatibility, breathability, and long-term wearability of the custom-built lens in a manufacturable manner.
Glucose-monitoring lenses for diabetics are just the start. The lens could be used to monitor numerous ocular diseases and even be used to deliver drugs directly to the eye itself. Purdue wants to focus on using the soft contact lens device to treat or manage ocular diseases rather than the glucose monitoring at this point.
Patients could potentially wear the soft contact lens as part of the management of chronic ocular diseases, with sensors and stimulators accessing the corneal surface, inner eyelids or both, in a non-invasive manner. The system could be powered wirelessly “all at home”, to provide the embedded therapeutic stimulation while the sensors can monitor the process. This eliminates the need for frequent hospital visits.
As contact lenses are already in contact with the eye, and cause minimal disruption to the wearer, they potentially make a useful new way to deliver a measured amount of a drug directly onto the eye’s surface, or monitor changes in the eye on a day-to-day basis.
Lee said that “at this stage, we have established the optimal materials, design layouts, and fabrication methods to generate prototype devices” and the university will soon move onto the first stage of testing the devices.
Work on similar devices is also being conducted elsewhere. A team at Kaunas University of Technology, Lithuania is working on dissolvable contact lenses that can deliver drugs to the eyes of glaucoma patients, while a lens that monitors the pressure within the eye — which spikes in glaucoma — has been developed at the University of Liverpool. Glaucoma is a key cause of preventable blindness.
A team at the Ulsan National Institute of Science and Technology (UNIST) in South Korea have demoed a prototype lens where the electronic components are isolated in ‘islands’ that are transparent and flexible, allowing the lens to be able to move and stretch around the eye’s surface.
So keep your eyes open for all these exciting new technologies. Here are a few more uses being developed for smart contact lenses.
Smart contact lenses could give you robot vision: the ability to record video, just by blinking your eye. Sony, Google and Samsung have all filed patents for digital contact lenses. Samsung just patented a smart contact lens with a built-in camera. Plans for lenses include capturing photos and video. The images would then be transfer wirelessly to a smartphone.
Augmented reality contact lenses are also in development. The technology behind “Google Lens”, which can identify most objects and locations it “sees”, could one day be integrated into the lens. Contact lenses that display and record information may not be far behind.
Do you think this all sounds like science fiction? Verily, a company owned by Google, has invented injectable contact lenses. Your natural lens is removed from your eyeball. A fluid is then injected into the eye, and that fluid fuses with the eye’s lens capsule as it solidifies. Ewww, gross you say! Inside this new, artificial lens lives storage, battery, sensors, a radio and other electronics. The artificial lens would take over the job of focusing light onto the retina, improving vision in numerous ways without glasses, but in a flexible, interactive way.
Researchers at the University of Wisconsin, Madison have invented a smart contact lens that can instantly focus the eye. It is under development as a future product for an Israeli company called Deep Optics. The idea is based on the eye function of the elephant nose fish. The lens uses electronic circuits and light sensors, which are powered by a solar cell, all built into the contact lens. When the sensors determine that the eye needs to focus, the chips command a small electrical current, which changes the focal length of the lens in a fraction of a second. The lens is designed to treat farsightedness, which affects nearly 1 billion people. The researchers say the technology is at least 5 years away. I can’t wait to be able to see the clock clearly when I wake up.
University of Michigan scientists are building a contact lens that can give soldiers and others the ability to see in the dark using thermal imaging. The technology uses graphene, a single layer of carbon atoms, to pick up the full spectrum of light, including ultraviolet light. The graphene was integrated with silicon microelectromechanical systems (MEMS). As you might expect, there’s some U.S. military funding behind the project.
I look forward to wearing smart contact lenses with wearables. The more devices we need that can be inside of us, the less gadgets we have to carry around with us. Hello 2025, I can’t wait until you get here!
What do you think of smart contact lenses? Please leave a comment or question in the box below and I will be happy to reply. Thanks for reading my post.