History Of Retinal

George David Wald

George David Wald (November 18, 1906 – April 12, 1997) was an American scientist who studied pigments in the retina. He won a share of the 1967 Nobel Prize in Physiology or Medicine with Haldan Keffer Hartline and Ragnar Granit. As a postdoctoral researcher, Wald discovered that vitamin A was a component of the retina. His further experiments showed that when the pigment rhodopsin was exposed to light, it yielded the protein opsin and a compound containing vitamin A. This suggested that vitamin A was essential in retinal function.

In the 1950s, Wald and his colleagues used chemical methods to extract pigments from the retina. Then, using a spectrophotometer, they were able to measure the light absorbance of the pigments. Since the absorbance of light by retina pigments corresponds to the wavelengths that best activate photoreceptor cells, this experiment showed the wavelengths that the eye could best detect. However, since rod cells make up most of the retina, what Wald and his colleagues were specifically measuring was the absorbance of rhodopsin, the main photopigment in rods. Later, with a technique called microspectrophotometry, he was able to measure the absorbance directly from cells, rather than from an extract of the pigments. This allowed Wald to determine the absorbance of pigments in the cone cells (Goldstein, 2001).

George Wald was born in New York City, the son of Ernestine (Rosenmann) and Isaac Wald, Jewish immigrant parents. He was a member of the first graduating class of the Brooklyn Technical High School in New York in 1922. He received his Bachelor of Science degree from New York University in 1927 and his PhD in zoology from Columbia University in 1932. After graduating, he received a travel grant from the US National Research Council. Wald used this grant to work in Germany with Otto Heinrich Warburg where he identified vitamin A in the retina. Wald then went on to work in Zurich, Switzerland with the discoverer of vitamin A, Paul Karrer. Wald then worked briefly with Otto Fritz Meyerhof in Heidelberg, Germany, but left Europe for the University of Chicago in 1933 when Adolf Hitler came to power and life in Europe became more dangerous for Jews. In 1934, Wald went to Harvard University where he became an instructor, then a professor.

He was elected to the National Academy of Sciences in 1950 and in 1967 was awarded the Nobel Prize for Physiology or Medicine for his discoveries in vision. In 1966 he was awarded the Frederic Ives Medal by the OSA and in 1967 the Paul Karrer Gold Medal of the University of Zurich.

Haldan Keffer Hartline

Haldan Keffer Hartline (December 22, 1903 – March 17, 1983) was an American physiologist who was a co-recipient (with George Wald and Ragnar Granit) of the 1967 Nobel Prize in Physiology or Medicine for his work in analyzing the neurophysiological mechanisms of vision. Hartline received his undergraduate education from Lafayette College in Easton, Pennsylvania, graduating in 1923. He began his study of retinal electrophysiology as a National Research Council Fellow at Johns Hopkins University, Baltimore, receiving his Doctor of Medicine (MD) degree in 1927.

Ragnar Arthur Granit

Ragnar Arthur Granit (October 30, 1900 – March 12, 1991) was a Swedish-speaking Finnish and later Swedish scientist who was awarded the Nobel Prize in Physiology or Medicine in 1967 along with Haldan Keffer Hartline and George Wald "for their discoveries concerning the primary physiological and chemical visual processes in the eye". When Finland became the target of a massive Soviet attack in 1940 during the Winter War (1939–1940), Granit sought refuge – and peaceful surroundings for his studies and research work – in the neighbouring capital of Sweden, Stockholm, at the age of 40. In the next year, 1941, Granit also received Swedish citizenship, which made it possible for him to go on with his work and live without having to worry about the war, which lasted until 1945 in Finland. Granit remained a patriotic Finn throughout his life. After the Finnish-Russian Wars, Granit kept homes both in Finland and Sweden. He and his wife are buried in Korpo, Finland. Granit was professor of neurophysiology at the Karolinska Institutet from 1946 to his retirement in 1967.