KAIST Develops Wireless OLED Contact Lens

A project at South Korea's KAIST research center has incorporated OLED light sources into a thin flexible contact lens, to create a next-generation ophthalmic diagnostic technology. The breakthrough 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, according to KAIST.

The new lens could in particular help clinicians to carry out electroretinography (ERG), in which the electrical responses of various cell types in the retina are measured. This typically requires a complex diagnostic arrangement, in which patients must keep their eyes open and remain still in a dark room while an external light source and imaging unit is held up to the eye.

To overcome these limitations, the KAIST team integrated an ultrathin flexible OLED approximately 12.5 microns thick into a contact lens electrode. It also equipped the lens with a wireless power receiving antenna and a control chip, completing a system capable of independent operation.

Most smart contact lens-type light sources developed for ocular illumination have used inorganic LEDs, commented KAIST, an approach leading to rigid devices and excessive heat accumulation, which limits usable light intensity. In contrast, OLEDs are areal light sources shown to induce retinal responses even under low luminance conditions.

In trials the KAIST device delivered a relatively low luminance of 126 nits but still successfully induced stable ERG signals, producing diagnostic results equivalent to those obtained with existing commercial light sources. Animal tests confirmed that the surface temperature of a rabbit’s eye wearing the OLED contact lens remained below 27 degrees C, avoiding corneal heat damage.