Carl Friedrich Richard Förster

Carl Friedrich Richard Förster (1825 to 1902) was a German ophthalmologist born in Lissa, today Leszno in Poland. He received his medical doctorate in 1849 and spent most of his career associated with the University of Breslau, where his assistants included Hermann Wilbrand and Hermann Rudolph Aubert. He is remembered for tests of visual acuity and for investigations of indirect, or peripheral, vision and of visual performance across the visual field, work done together with Hermann Aubert; the linear variation of visual performance they described is sometimes called the Aubert-Foerster law. The terms Förster perimeter and Förster's shift derive from his research, and the Förster perimeter was an instrument for measuring a person's field of vision. He also devised a specialised photometer to find the smallest amount of light that makes an object visible. In 1871 he distinguished negative from positive scotoma, a negative scotoma being a void in vision and a positive one an area of darkness, lightness or hallucinatory patterns.