A team of Korean researchers has developed a next-generation wireless ophthalmic diagnostic technology that replaces the existing stationary, darkroom-based retinal testing method by incorporating an “ultrathin OLED” into a contact lens.
This breakthrough, highlighted in ACS Publications, is expected to have applications in diverse fields such as myopia treatment, ocular biosignal analysis, augmented-reality (AR) visual information delivery, and light-based neurostimulation.
A media release from Korea Advanced Institute of Science and Technology (KAIST) said that a research team led by Professor Seunghyup Yoo from the School of Electrical Engineering, in collaboration with Professor Se Joon Woo of Seoul National University Bundang Hospital, Professor Sei Kwang Hahn of POSTECH and CEO of PHI Biomed Co, and the Electronics and Telecommunications Research Institute had developed the world’s first wireless contact lens-based wearable retinal diagnostic platform using organic light-emitting diodes (OLEDs).
This technology enables electroretinography (ERG), an ophthalmic diagnostic method that measures whether the retinal function is operating normally, simply by wearing the lens.
That eliminated the need for large specialised light sources and dramatically simplified the conventional, complex ophthalmic diagnostic environment, the release said.
Traditionally, ERG requires the use of a stationary Ganzfeld device in a dark room, where patients must keep their eyes open and remain still during the test. This set-up imposes spatial constraints and can lead to patient fatigue and compliance challenges.
To overcome these limitations, the joint research team integrated an ultrathin flexible OLED – approximately 12.5 μm thick, or 6–8 times thinner than a human hair– into a contact lens electrode for ERG. They also equipped it with a wireless power receiving antenna and a control chip, completing a system capable of independent operation.
For power transmission, the team adopted a wireless power transfer method using a 433 MHz resonant frequency suitable for stable wireless communication. This was also demonstrated in the form of a wireless controller embedded in a sleep mask, which can be linked to a smartphone – further enhancing practical usability.
While most smart contact lens–type light sources developed for ocular illumination have used inorganic LEDs, these rigid devices emit light almost from a single point, which can lead to excessive heat accumulation.
Animal tests confirmed that the surface temperature of a rabbit’s eye wearing the OLED contact lens remained below 27°C, avoiding corneal heat damage, and that the light-emitting performance was maintained even in humid environments – demonstrating its effectiveness and safety as an ERG diagnostic tool in real clinical settings.
Prof Yoo said that “integrating the flexibility and diffusive light characteristics of ultrathin OLEDs into a contact lens is a world-first attempt” and that “this research can help expand smart contact lens technology into on-eye optical diagnostic and phototherapeutic platforms, contributing to the advancement of digital healthcare technology.”
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