Multi-Electrode Electroretinography with Transparent Microelectrodes Printed on a Soft and Wet Contact Lens

Visual electrophysiology measurements are crucial in ophthalmology as they are frequently used for diagnosing and treating numerous ocular diseases. Therefore, optically transparent and flexible electrodes with high sensitivity at localized regions are in high demand. Here, it is aimed to develop a soft, transparent, multi-electrode system assembled on commercially available soft contact lenses and assess its application in measuring Electroretinography (ERG) responses in rabbits. A biocompatible multi-electrode system on commercial disposable soft contact lenses is successfully constructed, showing 95% cell viability, 82% optical transparency over the visible range, and good flexibility at 10% strain. Direct current (DC) voltage is used to produce a highly resistive overoxidized poly(3,4-ethylenedioxythiophene) (PEDOT) layer that covers all parts of the electrodes except the sensing region, which, owing to its high conductivity, can accurately measure electrical signals from local regions of the cornea. Spatially resolved ERG recordings of rabbits are obtained with superior signal quality using this multi-electrode system. Thus, this device is expected to be used in ophthalmic diagnosis in the future. Here, a novel approach for fabricating a soft, transparent, multi-electrode array on commercially available soft contact lenses is described that allows the collection of spatially localized ERG signals. The difference in electrode patterns results in different mechanical and optical properties. The fabricated ME-ERG device is able to collect the ERG signals from different regions of the rabbit eye. image