Catalogue Number: 4185
Improved 'Foriagraph' Unit
Category: Equipment
Sub-Category: Tests of binocular vision
Corporation: Ellis Optical Company
Year Of Publication/Manufacture: c 1930
Time Period: 1900 to 1939
Place Of Publication/Manufacture: Thornton Heath, Croydon, England
Publisher/Manufacturer: Ellis Optical Company
Description Of Item: Rectangular metal box 140 mm x 90 mm x 42 mm with black crackled enamel finish, enclosing two rotating discs each of ten apertures controlled from either side. Apertures 1 and 11 are open. Apertures 2 to 10 are filled with coloured glass (red, orange, green, blue and tricolour red, clear and blue) or white on black three character fixation tasks [412, 312, tin, sit (sit missing)]. Apertures 12 to 20 are filled with reduced apertures (3 mm and 1 mm) clear glass, frosted glass or larger font white on black three letter fixation tasks [512, 314, SIX, LIT (LIT missing)] or a white on black cross. White chart on reverse comprising a foriagraph muscle balance chart, the other side has slots for an interchangeable card, a near vision reading test featuring central aperture and around it four passages of text in named typefaces: Diamond, Pearl, Minion and Bourgeois. Also telephone directory entry, railway timetable London Victoria to Bromley South and musical staff (Card missing). Handle missing. Extendable measuring tape with finger ring 100 centimetres with millimetre graduations on top and dioptres underneath. Triple lens clips on upper surface to hold light red, dark red and green filters. (All missing).
Historical Significance: The Improved Foriagraph was designed to measure binocular functions: horizontal and vertical imbalance, amplitude of accommodation, suppression, angle of squint and near points of accommodation and convergence. It can also be used to measure cylinder axis, as a colour test and a near reading chart. It was available with a light source which acted as a handle. �A makeshift light source has been made for demostration purposes.
How Acquired: Donated by Helen Robbins
Date Acquired: 4/4/2022
Condition: Good
Location: Archive room. West wall. Unit 5 Drawer 2
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