Ida Mann was born in London on 6 February 1893, the only daughter of Frederick Mann OBE, a civil servant, and Ellen (née Packham). She was educated at Wycombe House School, London, and at the London Polytechnic before proceeding to the London School of Medicine for Women and St Mary's Hospital, Paddington, where she qualified in 1920 after winning various prizes. She undertook a research studentship at the Institute of Pathology and Research at St Mary's and a Plimmer Fellowship at Imperial College in 1921 and was Webb research scholar at the Royal Free Hospital in 1922. Her first appointment was as ophthalmic surgeon to the Elizabeth Garrett Anderson Hospital from 1922 to 1925 and during this time she passed her FRCS. From 1925 to 1949 she held appointments at the Central London Ophthalmic Hospital (Moorfields) where she was the first woman to be appointed senior surgeon. She also held the post of ophthalmic surgeon at the Royal Free Hospital from 1928 to 1939. Besides her great clinical and teaching ability her research work in the twenties gained her a DSc from London University and was published as a book, *The development of the human eye*, its successor being *Developmental abnormalities of the eye* (1937), both of which remain standard texts to this day. Another book, *The science of seeing* (1946) was intended for the lay reader and achieved great popularity, running to three editions. During the second world war she was head of the ophthalmic research team appointed by the Ministry of Supply (Chemical Defence Department) working on ophthalmic problems connected with war, and during this period became reader (1941) then Professor (personal chair) in Ophthalmology (1942), University of Oxford, the first ever woman professor in Oxford. Then began a period of research into cancer with Dr (later Professor) William Ewart Gye, FRS, the director of the Imperial Cancer Research Fund, whom she married in 1944. After his retirement in 1947 she resigned her chair and they both retired to Western Australia. After the death of her husband in 1952 she returned to research, investigating as consultant to the Western Australian Government, trachcoma in the aboriginals, and with Dorothy Perret was largely responsible for first culturing *Chlamydia trachomatis* in Australia and efforts to try to find an effective vaccine. She worked for the World Health Organisation in the SW Pacific, Asia and Latin America, work which led to her book *Culture, race, climate and eye disease*. Writing under her married surname and unused middle name, Caroline Gye, she wrote two fascinating travel books *The cockney and the crocodile* and *China 13* and an unpublished autobiography. She was elected Hon FRACS in 1955 and amongst many other honours and lectureships, was awarded the Howe Medal, the American Ophthalmological Society's highest award. She was awarded the CBE in 1950 and appointed DBE in 1980 for her services to aboriginal welfare. A well-loved consultant and a stimulating member of the local medical community, she was involved in many projects ranging from the early planning of the Western Australia Medical School and the founding of a chair of ophthalmology within the faculty to the organising of education for handicapped children She died in Perth, Western Australia on 19 November 1983.