1917 - Charles D Keeler opens his first practice at 47 Wigmore Street, London; 1933 - C Davis Keeler company established; 1939 - spectacle prescription factory moves from Jason Court, London to Windsor; 1946 - establishment of Keeler Optical Products Ltd; 1953 - Keeler Optical Products incorporated in Philadelphia, United States; 1986 - Dollond & Aitchison Group plc purchase Keeler Holdings Ltd with Keeler Ltd functioning as its specialist, autonomous instrument division; 1996 - Keeler acquired by Halma plc;