Visual Science in the Eighteenth Century

Abstract

Visual science had undergone a revolution in the seventeenth century. Two critical features necessary for understanding vision were uncovered in its first two decades by Johannes Kepler (Figure 1) and Christoph Scheiner (Figure 2). Kepler (1604, 1611) described how the eye operated as an optical instrument, focusing light onto the retina to form an image. His primary concern was to construct better optical instruments, and he analysed how images might be formed in the eye (see Park, 1997; Wade, 1998b). Kepler began by solving astronomical problems, which he recognized demanded a proper understanding of visual theory. His insight led him to the camera obscura (or pinhole camera), which in turn stimulated the thought that the eye with its aperture must function in a fairly similar but imperfect way. He tried to understand how the crystalline lens focused rays of light by using water-filled glass flasks. Kepler not only constructed what can be thought of as an early artificial eye, but was probably the first Western scientist to analyse pinhole images correctly (Lindberg, 1968, 1976; Smith, 1998).