Augmented Reality in a Contact Lens, Sourav Dutta and Parami Roy
Posted on April 12, 2012
Over the past 125 years, contact lenses have come a long way. What started off as relatively thick, brown glass eye coverings, first created by German ophthalmologist Adolf Fick, have evolved into biosensor-laden polymer lenses that can measure eye movement, glucose concentrations in tears and intraocular pressure. Now a team of researchers is investigating whether the integration of light-emitting diodes (LEDs), circuitry and antennas into modified contact lenses can transform them into miniature augmented reality displays.
Augmented reality is a live, direct or indirect, view of a physical, real-world environment whose elements are augmented by computer-generated sensory input such as sound, video, graphics or GPS data. It is related to a more general concept called mediated reality, in which a view of reality is modified by a computer. As a result, the technology functions by enhancing one’s current perception of reality. By contrast, virtual reality replaces the real world with a simulated one.
University of Washington associate electrical engineering professor Babak Parviz and his colleagues are starting off modestly. In the Institute of Physics Publishing’s Journal of Micromechanics and Microengineering they have reported development of a contact lens that, when worn, can display a single pixel to the wearer. The ultimate goal is to create a multipixel display that would let the wearer view digital text and images over his or her view of the physical world without so much as batting an eyelid.
Efforts are being made to implement augmented reality in a contact lens built with very small circuits and LEDs for bionic eyesight. These lenses will provide seamless access to information that appears right before our eyes without even using smartphones or doing brain implants. A lens with one LED powered wirelessly with RF has been built. To turn a conventional contact lens into a functional system, control and communications circuits are integrated into the lens using custom built optoelectronic components. These components will eventually include hundreds of LEDs, which will form images in front of the eye, such as words, charts, and photographs. Much of the hardware is semi-transparent so that wearers can navigate their surroundings without crashing into them or becoming disoriented. In all likelihood, a separate, portable device will relay displayable information to the lens’s control circuit, which will operate the optoelectronics in the lens.
This technology can be used in various fields. A lens with a single pixel could aid people with impaired hearing or be incorporated as an indicator into computer games. The repertoire could be expanded to include displaying text, translating speech into captions in real time, or offering visual cues from a navigation system.
Besides visual enhancements, non-invasive monitoring of the wearer’s biomarkers and health indicators could be a huge future market. Several simple sensors have been built that can detect the concentration of a molecule, such as glucose. Sensors built onto lenses would let diabetic wearers keep tabs on blood-sugar levels without needing to prick a finger. The glucose detectors which are being evaluated now are a mere glimmer of what will be possible in the next 5 to 10 years. An appropriately configured contact lens could monitor cholesterol, sodium, and potassium levels, to name just a few potential targets. Coupled with a wireless data transmitter, the lens could relay information to medics or nurses instantly, without needles or laboratory chemistry, and with a much lower chance of mix-ups.
Three fundamental challenges stand in the way of building a multipurpose contact lens. First, the processes for making many of the lens’s parts and subsystems are incompatible with one another and with the fragile polymer of the lens. To get around this problem all devices have to be made from scratch. These components can’t be manufactured directly onto a lens. To fabricate the components for silicon circuits and LEDs, high temperatures and corrosive chemicals are used. That leads to the second challenge, which is that all the key components of the lens need to be miniaturized and integrated onto about 1.5 square centimetres of a flexible, transparent polymer. Last but not least, the whole contraption needs to be completely safe for the eye. Take an LED, for example. Most red LEDs are made of aluminium gallium arsenide, which is toxic. So before an LED can go into the eye, it must be enveloped in a biocompatible substance.
Several other nanoscale biosensors have been fabricated that respond to a target molecule with an electrical signal; several microscale components, including single-crystal silicon transistors, radio chips, antennas, diffusion resistors, LEDs, and silicon photo detectors have been constructed which can be connected by micrometer-scale metal interconnects necessary to form a circuit on a contact lens. Prototype lenses with an LED, a small radio chip, and an antenna have been fabricated which is powered wirelessly, lighting the LED. Such types of lenses have been successfully tested in trials with live rabbits after encapsulating them in a biocompatible polymer to make it safe.
You might be able to say hasta la vista to your normal old contact lenses and hello to the wirelessly powered augmented lenses. Obviously it’s going to take a lot more work before we have the computer-enhanced cyborg vision in the Terminator movies, but you never know what could happen in the next 18 years—the future portrayed in those films is 2029.