| Description | Leather cover securing a Keeler Recording Perimeter, an optical instrument used to measure the visual field. The arc-shaped, graduated device, made by Keller, includes a cable for mechanically registering results, with enclosed light, and a chin rest for the patient. It was used by Dr O'Quigley, Chief Medical Officer at Aer Lingus from the 1940s to the 1960s, and was given by him to Dr P. MacMaghnais in 1970. |