Fincham coincidence optometer

Catalogue Number: 2869
Fincham coincidence optometer
Category: Equipment
Sub-Category: Optometer
Designer/inventor: FINCHAM Edgar F
Year Of Publication/Manufacture: Originally made 1935.
Time Period: 1900 to 1939
Place Of Publication/Manufacture: England
Publisher/Manufacturer: Taylor, Taylor and Hobson Ltd
Description Of Item: Brown crackle and enamel finish metal optometer with a meridian and a power dial. patient headrest and examiner eye piece. A table top ophthalmic instrument devised to measure refractive error. It uses image doubling of a line object so that precise determination of the refractive error could be made by vernier alignment of the doubled line. The line object can be rotated to determine the principal meridian of astigmatism. Inscribed by the manufacturer with 'Made for Clement Clark and Co Ltd by Taylor, Taylor and Hobson Ltd, England No. 104/94 - 100). Also inscribed on one side are the British and US patents taken out.
Historical Significance: The instrument was developed in 1935. It was exhibited in 1935 at the 25th exhibition of instruments of the Physical Society (See Inst Physics online archive http://gita.grainger.uiuc.edu/iop/JournalArticle.asp?issn=0034-4885&volume=3&issue=1&artnum=323&lang=) and Fincham published the principles of the instrument in 1937. It is an example of ingenuity to find better ways of measuring refractive errors but the instrument was never widely used. See Fincham EF. The coincidence optometer. Proc Physical Soc, 1937; 49, (5): 456-468 and R E Reason. The development of the Fincham coincidence optometer Proc. Phys. Soc. 1937; 49: 469-478 doi:10.1088/0959-5309/49/5/304. The optical principles are described in Smith G and Atchison DA. The eye and visual optical instruments Cambridge Press 1996. EF Fincham (1893 - 1963) FIntPhys FSMC FBOA taught in the optometry course at the Northampton Polytechnic in London, later City University. He was the inventor of a number instruments including the Fincham ophthalmo-retinoscope (see cat No 1124), the Fincham Plastic Artifical Eye Fitting Set, the Fincham photo-retinoscope, Fincham Sutcliffe screening scotometer, the Electronic field-plotting chart and the Fincham combined corneal microscope and slit lamp. He also published a number of scholarly papers of accommodation and other subjects. See obituary Br J Ophthalmol 1964; 48: 120. This instrument was previously owned by Anthony Douglas, optometrist in Ballarat, Victoria from 1945 to about 1985. See Cat No. 0629 for another example.
How Acquired: Donated by Graham Sheil, European Eyewear, Melbourne
Date Acquired: May 2016
Condition: Good except power lead is missing
Location: Archive room. East wall Unit 4 Cupboard

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