Whether you’re trying to find a new pair of smart lens contacts or are looking for a replacement for the ones you already own (in the near future), it’s important to understand how the technology works.
Structures
Several researchers are working to develop smart lens contacts. These contacts could one day serve as a noninvasive, wireless health monitoring device that could reduce the burden of blood sugar monitoring for diabetics. But to make them a reality, they must address several important issues.
One important issue is haze. The optical transparency of a contact lens is crucial for reliable operation. Fortunately, transparent nanomaterials offer superb reliability. These nanomaterials can also undergo mechanical deformation without damage. The best part is that they don’t obstruct the wearer’s view.
The smart lens also has a glucose sensor integrated with a light emitting diode (LED) pixel. This pixel turns off when the concentration of glucose exceeds a certain threshold. It also has a wireless power transfer circuit. This circuit increases the transmitting coil temperature.
The smart lens also has a parylene coating to protect the AgNF-based electrodes from tear fluid. This layer also acts as a diffusional barrier. The structure of the smart lens has a few other features.
For instance, the transparent and stretchable AgNF-based antenna is located on the elastic region. This allows it to receive ac signals without obstructing the wearer’s view. Another is the single-loop antenna that can be located outside the pupil of the eye.
Other features include the hybrid substrate and its reinforcing islands. The hybrid substrate is composed of heterogeneous materials that offer high oxygen permeability and low haze. This allows the contact to effectively distribute mechanical strain. It also has well-matched indices for high optical transparency.
Sensors
Among the many applications of smart lenses is the ability to monitor glucose levels in the tear fluid of diabetic patients. Glucose is one of the major risk factors for diabetes. This sensor could be used for diabetic screening as well as noninvasive health care monitoring of glucose and other metabolites using the tears of contact lens users.
In this study, a smart contact lens was designed to incorporate a wireless glucose sensor with a display pixel. The pixel turned off if glucose concentration reached a threshold.
The device was fabricated in the same way as a conventional contact lens. It contains a silicon / parylene hybrid substrate, a graphene channel, a microfluidic chip and two piezoelectric sensors. The device’s display pixels enable real-time data access.
The contact lens sensing platform is capable of monitoring glucose levels in real time. The device can replace the standard finger prick method of glucose monitoring.
The device has demonstrated a high degree of reliability in human tests. Results showed that glucose concentrations were comparable to those measured by a traditional glucometer. The smart lens also exhibited repeatability when used over multiple cycles. The frequency response was almost linear when applied to small pressures. The device also showed impressive mechanical durability.
This device was also tested on a bovine eyeball. The bovine eyeball’s structural resemblance to the human eyeball allowed researchers to conduct in vivo tests. The device successfully measured glucose and intraocular pressure in the eye.
In vivo tests with a live rabbit
Several in vivo tests with a live rabbit have been conducted to evaluate the performance of a smart lens. The results indicate the need for improved high-resolution displays and remotely powered displays.
A prototype electronic contact lens was developed by researchers at the University of Washington and Aalto University. It features a transparent sapphire chip containing a custom-designed micro-light emitting chip and a 500 x 500 um2 silicon integrated circuit. It also includes insulation layers and a 5-millimetre-long antenna.
In vivo tests with a live rabbit showed no adverse effects from the lens. A 40-minute test session with the lens showed no corneal abrasion. It also demonstrated no irritation or other problems. After the test, the rabbits were fed.
The contact lens sensor can be used to detect glucose in tears. In addition, it can be used to measure resistance and intraocular pressure (IOP). The glucose sensor is integrated with a LED pixel. The glucose level in tears correlates with the blood glucose level. This noninvasive approach to detecting metabolites in tears is promising.
The University of Washington and Aalto University researchers have built prototype electronic contact lenses for in vivo tests with a live Rabbit. The contact lens contains several components, including a radio integrated circuit, metal interconnects, a silicone elastomer, a 750 x 750 um2 single pixel display, a 500 x 500 um2 piece of silicon, and an antenna. It is designed to be stretchable and can be used to measure physiological parameters without interfering with the user’s vision.
Treatment of glaucoma
Developed by a Chinese team, smart lens contacts for treatment of glaucoma are a potential medical device that could be used to monitor intraocular pressure (IOP) in patients. The contact lens is made from soft material and features pressure-sensing circuits that are integrated into the design. These sensors detect pressure changes and send a signal to a wireless system, which then orders the hydrogel to release a drug to counteract the pressure.
The first prototype of the smart contact lens was developed by electrical engineer Cheng Yang, who has designed a contact lens with multiple sensors embedded in it. He and his colleagues found that the pressure-sensing circuits were able to sense changes in the pressure inside the eye.
When the sensor sensed a change, the wireless system would order the hydrogel to release brimonidine, a drug that reduces pressure within the eye. The drug was then injected into the cornea through a curved surface of the lens.
The drug lowered the eye’s IOP near the normal range. Researchers tested the contact lens on live rabbits. The results were encouraging. However, more studies are necessary before testing the device on human eyes.
Eventually, the system may be integrated with a DDS (digital diagnostic system) to accurately monitor and control IOP. This could open up a new approach to personalized glaucoma treatments.
The device also includes a wireless feedback system that can be used to monitor IOP. This could help determine whether the patient is developing glaucoma. It can also help predict the progression of the disease.
Glucose sensing
Glucose is a risk factor for diabetes and monitoring glucose non-invasively has been around for a while. However, isolating glucose molecules with sensors has never been cheap or practical. Several companies have tried to develop needle-free blood sugar monitors, but none of them have been successful.
Google has been working on a smart contact lens that could potentially replace the invasive blood sugar test. They say it could be ten times better than current technology. They’ve put together a small chip, antenna, and wireless reader coil that could wirelessly transfer power to the contact lens.
The small LED light pixel could turn off when glucose concentration in the tear fluid exceeded a pre-determined threshold. This isn’t the first time Google has pushed the envelope, but it’s the first time they have been able to demonstrate an in-vivo glucose sensing system.
One of the smart contact lens’s main features is a small LED light. It’s only visible to the wearer, and would be the first to show up if the glucose concentration in the tear fluid exceeded a certain threshold.
The smart contact lens also boasts a resonant inductive wireless energy transfer system, which can wirelessly transfer power to the lens. It’s also got a real-time electrochemical biosensor, which can detect glucose concentrations in the tears of diabetics.
One of the biggest questions about smart contact lenses is how to produce the device at a reasonable cost. This is why Google is looking to partner with experts in the field. They might be able to help subsidize continued R&D.
Eye-cleansing sensor
Using intelligent contact lenses to monitor the health of the eye has the potential to enhance health care. This technology provides a non-invasive means to monitor several biomarkers, including glucose, in tears. It can also maintain eye temperature without abrupt heating. These devices have numerous applications, including monitoring intraocular pressure and detecting biomarkers associated with ocular diseases. In addition, these devices can be fabricated from transparent nanomaterials.
Smart contact lenses can be made with transparent nanomaterials that can be incorporated into the lens material. These materials can undergo mechanical deformations without damage and can be used to form a diffusional barrier to prevent tear fluid from leaking through the device. They also provide superb reliability and excellent stretchability. These materials also present wide ranges of superior transparency.
For example, an IC chip embedded in a smart contact lens is seven times stiffer than a typical soft contact lens. This stiffness is responsible for reducing the resistance of the sensor and reducing the risk of corneal hypoxia. It can also help prevent irritation from foreign objects.
In addition, a wireless display was integrated with a glucose sensor. This display is capable of detecting changes in the concentration of glucose and displaying information in real time. The LED pixel turns off if glucose concentration exceeds a threshold value.
This smart contact lens system is also stable and reliable. It exhibited a minimum rate of degradation after 5000 cycles. In addition, it was stable during repeated blinks.
