Routine examination with the British Refracting Unit
 Catalogue Number: 780 Routine examination with the British Refracting Unit Category: Book Sub-Category: Manual, for instruments etc Author: STEARMAN S R Year Of Publication/Manufacture: c 1930 Time Period: 1900 to 1939 Place Of Publication/Manufacture: London Publisher/Manufacturer: S Pulzer and Son Ltd Description Of Item: Original papered board, 20 pages. Rubber stamp for Australian Optical Company on front cover and title page Historical Significance: Refractor heads (also known as phoropters in the USA and refracting units in the UK) were first devised between 1917 and 1940 to make refraction quicker than when a trial lens set and trial frame were used and they also held devices such as Maddox rod and Risley prisms for the measurement of heterophoria. In fact the first phorometers were devised for this latter purpose early in the 20th C. (See Cat no 175, 351 and 550). Spherical and cylindrical lenses on rotary discs were added later. The British Refracting Unit was first made about 1930. Two British Refractor units are held in the Kett Museum (Cat no. 1123, 1139). A similar brochure for the British Refracting Unit by the same author is at Cat no. 3246. How Acquired: Donated by Australian Optical Company Condition: Excellent Location: Archive office. Pamphlet and ephemera filing cabinet. Drawer 1 |