Editing Hermann von Helmholtz (section)

===Ophthalmic optics===

In 1851, Helmholtz revolutionized the field of [[ophthalmology]] with the invention of the [[ophthalmoscope]]; an instrument used to examine the inside of the [[human eye]]. This made him world-famous overnight. Helmholtz's interests at that time were increasingly focused on the physiology of the senses. His main publication, titled ''Handbuch der Physiologischen Optik'' (''Handbook of Physiological Optics'' or ''Treatise on Physiological Optics''; English translation of the 3rd volume [https://web.archive.org/web/20180320133752/http://poseidon.sunyopt.edu/BackusLab/Helmholtz/ here]), provided empirical theories on [[depth perception]], [[colour vision]], and [[motion perception]], and became the fundamental reference work in his field during the second half of the nineteenth century. In the third and final volume, published in 1867, Helmholtz described the importance of [[unconscious inference]]s for perception. The ''Handbuch'' was first translated into English under the editorship of [[James P. C. Southall]] on behalf of the [[Optical Society of America]] in 1924–5. His theory of [[accommodation reflex|accommodation]] went unchallenged until the final decade of the 20th century.

Helmholtz continued to work for several decades on several editions of the handbook, frequently updating his work because of his dispute with [[Ewald Hering]] who held opposite views on spatial and colour vision. This dispute divided the discipline of physiology during the second half of the 1800s.