Jack Yellott's History of Vision Science

The material on this page was created by Jack Yellot at UC Irvine, and was originally published on his UCI website. Sometime after his passing it disappeared from the UCI web, but fortunately for us it was preserved in the Wayback Machine archival site.

Back to CVNet

Visual Science Before 1600

The roots of modern visual science reach back twenty-five centuries to the earliest Greek writers: Polyak's (1957) account of this history is especially recommended. (See also Borin, 1942, and Duke-Elder, 1958, 1961, 1968, 1971).

From antiquity to the early 17th century the outstanding problem was the nature of the physical connection between eyes and objects. Many classical writers (including Euclid and Claudius Ptolemy) conceived of this in terms of rays emanating from the eye, so that vision could be understood as a form of touch. This idea persisted for a very long time, and vestiges of it survive even today in popular thought. For many purposes it is optically equivalent to the correct interpretation, and consequently not entirely useless: Brunelleschi and Alberti were able to work out the theory of perspective pictures early in the 15th century, nearly two-hundred years before emanationist notions were finally laid to rest. It is also worth noting that spectacles were in common use by that time, notwithstanding the complete absence of any theory to explain why they worked.

The alternative (and of course ultimately correct) view was that objects send out copies of themselves, which travel to the eye and are there somehow incorporated into the body. Under this hypothesis the important questions had to do with the physical nature of these copies, and the anatomical site of their incorporation. On the latter point, classical opinion (e.g., Galen) favored the lens, perhaps simply because its striking appearnace suggests a miraculous function. This notion persisted until late in the 16th century, despite a growing familiarity with the image forming properties of convex lenses: it was accepted even by Giovanni della Porta, who first added a lens to the pinhole camera and thereby invented the modern camera (1589). However, it could not long survive Felix Platter's demonstration (1583) that vision continues after the lens has been isolated by cutting it suspensory ligament. Platter believed photoreception occurred in the retina, but lacked an optical basis for this hypothesis, as well as experimental verification.

The problem was finally resolved in the early part of the 17th century by Kepler's theoretical explanation of the optics of the eye (1604), followed by Christopher Scheiner's direct experimental demonstration that an optical image is indeed formed on the inside rear wall of the eyeball (1625). These two events mark the beginning of modern visual science, and lead directly to the questions that have subsequently occupied the field: How is the retinal image kept in focus? What anatomical structures actually capture the light, and how is this accomplished? What sort of physiological signal does this give rise to? How is this signal processed within the eye? How is it transmitted up the optic nerve? What is its destination in the brain? And the fundamental underlying question: How are these physical processes related to visual perception?

The dates in the chronology of major events in visual science from 1600 to 1960 are taken from a number of secondary sources (which sometimes disagree), and should probably be regarded as accurate to within roughly a decade. Sometimes a discovery evolves over many years and many publications; in this case I try to use the earliest. In addition, there are always disputes about priority: I try to use the name of the investigator most closely associated with an achievement in preference to one who might have suggested an idea in a more or less casual fashion, unrelated to subsequent developments within the field. For instance, I credit Helmholtz rather than Babbage with the ophthalmoscope. Besides the references cited at the beginning, dates have been taken from Pledge, 1950; Brindley, 1970; Blackwell, 1972; Baumgardt, 1972; Kelly, 1972; Westheimer, 1972; and Davson, 1976.

This chronology was originally prepared as part of a handbook chapter in but ultimately seemed inappropriate for that purpose, though still perhaps worth distributing in this new context. I thank T.N. Cornsweet and B. Wandell for helpful comments.

Visual Science 1600-1960