Born in London 14 December 1863 son of Thomas Allen Green, whose family were makers of Crown Staffordshire ware. He was educated at St John's College, Cambridge, the Newcastle Medical School, and St Bartholomew's Hospital. He held resident posts at the Royal Victoria Infirmary, Newcastle-on-Tyne, and at Northumberland House Asylum, and was appointed medical superintendent of Hendon Grove Asylum. The year after he qualified he published a useful book on *Memory* in the then well-known International Science series, which reached a second edition. He made an original study of colour blindness, won a gold medal with his MD thesis on this subject, attacking the Holmgren wool-test and putting forward his own theories of the function of the retinal rods and visual purple. Through Sir Lauder Brunton his work was presented to the Royal Society, but in 1892 their committee unanimously recommended continuing the Holmgren tests, for railways and ship-owners. However in 1904 the Ophthalmological Society confirmed Edridge-Green's conclusions. He revised his monograph of 1891, *Colour blindness and colour perception*, in 1909, his conclusions were supported by the work of Doyne and Gotch at Oxford, and in 1912 the British Association reported in his favour. His colour perception spectrometer and lantern and his bead tests were subsequently adopted by the Royal Navy and by the selection boards for the Services. He became a special examiner and adviser on vision to the Ministry of Pensions, ophthalmic surgeon to the London Pensions Board, and chairman of the ophthalmic board of the Central London medical boards for National Service. The Board of Trade changed to his methods in 1915, during the first world war, in their recommendations to the railways and shipping-lines, and he was appointed their adviser in 1920; he was also adviser to the Ministry of Transport. His best book *The Physiology of Vision* appeared in 1920. At the College he was a Hunterian Professor in 1911 and an Arris and Gale Lecturer in 1920. He received a Beit Memorial Research Fellowship, was a Président d'honneur of the Société d'Ophtalmologie of Paris in 1930, and was awarded the Thomas Gray prize in 1936 for the invention of his lantern. He served on the International Code of Signals committee from 1892 and was created CBE in 1920 for his war-work. He was President of the Durham Medical Graduates Association. Before taking up ophthalmelogy he had made some researches on memory and mind functions. Trained as a psychiatrist, his discovery of the mechanism of colour vision led him into prolonged controversies in pressing its practical application. Edridge-Green married in 1893 Minnie Jane daughter of Henry Hicks MD, FRS the geologist. She died in 1901 and their two sons died before their father. He died in a nursing-home at Worthing on 17 April 1953 aged 89. He was a bearded, shy man, who retained the look and manner of a late-Victorian man of science into the mid-twentieth century. He bequeathed to the College his portrait painted by F Walenn in 1895, with the gold medal awarded him by the University of Durham. The College also possesses an excellent caricature portrait drawing by George Belcher RA, presented by J Pike in 1957. Edridge-Green bequeathed £3000 to found an annual lecture at the College on vision or colour vision; the first lecturer was appointed in 1955. Principal Publications: *Memory: its logical relations and cultivation*. Bailliere, 1888. *Colour Blindness and Colour Perception*. 1891; 2nd edition 1909. The relation of light perception to colour perception. *Proc Roy Soc*. 1910, B-82. *Colour Vision and Colour Blindness* (Hunterian lectures) 1911. The discrimination of colour. *Proc Roy Soc*. 1911, B-84. *The Physiology of vision*. Bell, 1920. 292 pages. Colour vision and colour blindness. *Encyclopaedia Britannica* 1922. *Science and Pseudo-science* (partly autobiographical). Bale 1933. The solution of the problem of vision. *Chemistry and Industry*, 12 August 1939.