Design and Implementation of Dry Eye Detection Illumination Imaging System Based on Placido Disc

Abstract A lighting imaging system for dry eye testers is designed for the Placido disc features. Among them, the illumination light source adopts the flexible circuit board annular 850 nm LED light source, light through the Placido disc that can make the eye table brightness and illumination uniformity, it is conducive to obtain a clear eye plaque Placido annular image using the image acquisition system. At the same time, an imaging objective lens with a working distance of 100 mm is designed, and the objective lens has a MTF value of more than 0.3 at a spatial frequency of 135 lp/mm in the full field of view. It corrected various aberrations well and obtained excellent photo quality. The results show that this design can clearly display the annular Placido disc images on the tear film.