The Busch-Thorner optometer (Thorner's eye refractometer)

Catalogue Number: 1621
The Busch-Thorner optometer (Thorner's eye refractometer)
Category: Papers
Sub-Category: Manual, for instruments etc
Designer/inventor: THORNER Walther
Year Of Publication/Manufacture: c 1930
Time Period: 1900 to 1939
Place Of Publication/Manufacture: Germany
Publisher/Manufacturer: Emil Busch A-G
Description Of Item: Booklet in English on the design and method of using Thorner's optometer, black and white photograph of the instrument on cover (no title) 12 pages, 8 figures, price list for the refractometer and accessories on page 11.
Historical Significance: United States Patent 3634003 for an OPTICAL SYSTEM FOR IMAGING SCHEINER APERTURES IN AN OPTOMETER was issued to Walther Thorner in July 1917 - 1235170 indicating that this instrument was devised in or before 1917. There are a number of papers in the literature reporting it or its use in investigations in the late 1920s. eg an exhibit of it by Emil Busch Optical Co., Ltd. reported in Trans. Opt. Soc. 1929; 31: 40 doi: 10.1088/1475-4878/31/1/305 and one in Scandinavica Acta Ophthalmologica 1928; 6:1-4. Judging by the cover photograph the booklet is likely to date in the 1930s. It has also been used in more modern investigations (eg Le Grand and El Hage, 1980, J Pujol, J Gispets, M Arjona 2003. The patent identifies Thorner as a subject of the King of Prussia living in Berlin. The patent describes it 'In an optometer of the type employing Scheiner apertures, an optical system is disclosed for projecting those apertures into a plane proximate to the eye, most commonly the plane of the pupil. According to the arrangement of the system, the plane of projection of the apertures and the plane of refraction, that is, the vertex distance of refraction, are separable.' It seems that the Fincham coincidence optometer (See Cat No 629) may be a development of the Thorner optometer. See Fincham The coincidence optometer. Proc Phys Soc 1937
Condition: Very good
Location: Archive office. Pamphlet and ephemera filing cabinet. Drawer 4

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