The Study Of Phosphene Size Perception Based On Tactile Judgment Using Simulated Prosthetic Vision

Implantable Visual prostheses have been proposed as a therapy for the blind with AMD and RP. Discrete visual perception called phosphenes which can be reliably elicited in the visual field after electrical stimulation. The generating perception of phosphenes in blind people is the cornerstone of ongoing attempts by several groups to provide a visual prosthesis. So it is very important to study the characters of phosphenes. In order to effectively convey useful information to blind individuals, it is crucial to accurately determine the coordinates of all phosphenes, including size, position, shape, colour and distribution. Here we are presenting one device based on tactile perception to address the phosphene size evaluation procedure.In this study, four experiments were designed to investigate size perception performance based on tactile board. The four experiments were to evaluate the effect of phosphene brightness, the effect of flickering, the effect of phosphene mapping and the effect of different processing methods of tactile boards. There are two tactile boards. One is with depressed round hole and the other is with raised round column.The results of this study are as follows: it is proven that phosphene size perception performances could be accurately expressed through tactile perception; the brighter stimuli were perceived as significantly larger than darker ones; the flickering stimuli were perceived as larger than nonflickering ones; the more eccentric stimuli were perceived as significantly larger than less ones, and the standard deviation (SD) of foveae viewing appears to be the lowest; the subjects did better size matching work using the second tactile board (column) than the first one (hole).