Computer simulation of Purkinje-Sanson images for the biofeedback therapy of myopia

In order to treat pseudo-myopia, the authors have proposed a biofeedback therapy system with real time feedback of a patient´s eye-lens thickness using Purkinje-Sanson (PS) images. The PS images are recorded with an infrared video-camera during lightening by visible LED light. After the images are digitized by a personal computer, the PS parameters (distances between the images or the area of the images) are calculated in order to estimate the lens thickness. The measured data show good coincidence with the anatomical data of extracted pigs eyes. Several clinical measurements on normal and nearsighted subjects show good correlations with r=0.958 between the real distances from the objects and the PS parameters. Computer simulations based on the optical model of the PS images are executed too, which show relative good coincidence with the real object´s distances