Extraocular Muscles and their Effect on the Shape of the Eye

The following works, two centuries old, provide evidence that accommodation of the eye to different distances is a result of the extraocular muscles changing the shape of the cornea or of the eye as a whole. They are reprinted from Philosophical Transactions of the Royal Society of London, 1794-1802. Conspicuously absent from this collection is the work by Thomas Young, whose theory that was the lens and the lens only changes in shape during accommodation. He published two articles in defense of his theory, one in 1794, and another (his most famous and widely cited), in 1801. Young's theory is the only one that prevails today in "scientific" circles, with the exception that Young thought the lens to contain muscles, and now the ciliary muscles are said to be responsible for controlling the lens's shape, as was proposed by Hermann von Helmholtz in the 1840s.

While most have abandoned the theory that the cornea is a dynamic part of the eye, a few 20th century experiments support the idea that the cornea changes more rapidly than is usually assumed.

In 1931 Optometrist J.W. Parker wrote an article on instant Changes in Corneal Astigmatism evidently produced by the extraocular muscles.

See also the bibliography, The Incredible Changing Cornea.

Back to I SEE library...
Revised 26 February 1996