Zeiss focimeter (Lensometer, vertometer)
 Catalogue Number: 1905 Zeiss focimeter (Lensometer, vertometer) Category: Equipment Sub-Category: Vertometer, lensometer, focimeter Year Of Publication/Manufacture: 1932 Time Period: 1900 to 1939 Place Of Publication/Manufacture: Jena, Germany Publisher/Manufacturer: Carl Zeiss Description Of Item: Focimeter (syn vertometer, lensometer, lensmeter) for the measurement of ophthalmic lens powers, black metal, round base with slender stem adjustable for height, focussing knob with dioptre scale, rotating axis scale, adjustable ledge to locate lens and retractable spring to hold lens in place, adjustable eyepiece with rotatable flange with lenses to view the cylindrical lens axis scale and the lens power scale, slide-on metal lamp housing with electric cord and plug. 290 mm high. Marked 'CARL ZEISS/JENA/NO 1880' Historical Significance: The principle of the optical design of an instrument for measuring lens power was established by Snellen in 1876 but he used it as a phakometer. Troppmann introduced the first focimeter in 1912 in which dioptric power could be read off a scale. Previously opticians had used the lens curvature measure (spherometer). Carl Zeiss produced its first focimeter in 1915. This version is dated 1932 by the British Optical Association museum. Vertometer is the brand name of Bausch and Lomb focimeters and Lensometer the brand name for the American Optical Company instrument (1921). Cat No 2110 is a similar item in better condition but lacking the light housing Condition: Poor Extensive corrosion of base and stem particularly Location: Archive room. West wall. Unit 2 Overhead display |