Information throughput characteristics--a new method for evaluation of visual efficiency

A method based on information theory for computer-aided assessment of visual capacity has been elaborated. In this method, the rate of recognition of visual targets is considered along with the accuracy of perception. Measurements are performed in a wide range of optical stimulus intensities (the Landolt ring size ranging from 0.125 to 1.57, in 10 logarithmic steps). For each step the information throughput (IT) is calculated and the results are displayed as a function of stimulus intensity. Thus, the IT characteristics of the visual system, with regard to motor response, are obtained. Within the reported range, they reveal low-pass properties of the system. Preliminary experiments show that these curves are useful in the evaluation of visual performance, especially in ergophthalmology. A recently developed IBM PC-based system for automatic measurements of the IT characteristics is described. Some aspects of application of the method are also discussed.