The world's first contact lens with an OLED display 6 times thinner than a hair

South Korean researchers have created the world’s first wireless contact lens with an OLED display for the diagnosis of retinal diseases.

It is noted that this tiny lens uses an integrated organic LED to conduct electroretinography. This procedure measures the electrical response of the hypersensitive cells in the eyes to diagnose hereditary diseases of the retina or to assess its functional decline.

Usually Electroretinography is performed in specialized conditions with certain restrictions. Patients are in a dark room and look at a large stationary device called the «Ganzfeld», which sends flashes of light into their eyes. Patients are required to remain still with their eyes open, which may seem difficult and tiring, especially for children. 

However, a group of researchers from The Korea Institute of Science and Technology (KAIST) has greatly simplified this procedure. The researchers integrated a flexible OLED into the electrode of a contact lens for ERG. The thickness of OLED is only 12.5 microns, which is 6-8 times thinner than human hair.

In addition, the researchers made the system fully autonomous by equipping the lens with a wireless antenna and a control chip. The device uses a method of wireless energy transmission at a resonant frequency of 433 MHz. This frequency is ideal for stable wireless communication.

The practical application of the technology was demonstrated using a wireless controller built into a sleep mask that can be connected to a smartphone. Most modern smart lenses use inorganic LEDs with high rigidity and light emission from a single point. This can lead to excessive heat and limited light intensity. 

The new technology uses OLED displays, which are sources of real light It is safe for the eyes, does not overheat, and provides clear and stable ERG signals even at low brightness of 126 nits. The efficacy and safety of OLED contact lenses for clinical use has been proven in animal studies.

The study showed, that the lens keeps the surface temperature of the eye below 27°C, preventing heat damage of the cornea. The lens also retained light-emitting properties in conditions of high humidity, demonstrating its reliability as an ERG diagnostic tool. This innovation is expected to simplify the diagnosis of retinal diseases and find potential applications in various fields, such as myopia treatment, augmented reality, and light neurostimulation.

Source: Interesting Engineering