ABSTRACT
Light is the stimulus for vision and the eye is the organ which responds to light energy. This chapter will examine two contemporary developments from the heritage of perception that are actively being pursued. One concerns advances in our understanding of the nature of the stimulus-visual optics. The other is about how the visual system responds to light-visual neurophysiology. The image-forming properties of the eye are quite well understood, and most aberrations of the eye can now be corrected optically. The performance of the human eye is remarkable considering that its optical parts are so simple. One of the ways of measuring the performance of the visual system is to treat it as a physicist would a lens, by determining how faithfully it can transmit patterns of light incident upon it. One outcome of this approach has been the suggestion that the visual system is most sensitive to sharply defined contours and also to spatially periodic patterns of parallel lines (referred to as gratings).
