Catalogue Number: 3484
Projection scotometer of Juler
Sub-Category: Perimeter, visual field analyser
Designer/inventor: JULER Frank A
Year Of Publication/Manufacture: 1951
Time Period: 1940 to 1999
Place Of Publication/Manufacture: London. UK
Publisher/Manufacturer: C Davis Keeler Ltd
Description Of Item: The projection scotometer is a device for projecting light spots on to a Bjerrum screen for plotting field losses in the central visual field. It is designed to replace Traquair targets for central field perimetry. The instrument has a handle through which the electric lead enters, a ventilated light housing, a metal rotating disc to change target size and colour and a long tube to optically focus the target on the Bjerrum screen. Overall length is 43 cm. The handle is marked Keeler England. The associated transformer is not original being marked Radio Parts Ltd Adelaide, South Australia.
Historical Significance: Traquair perimetry targets were white and coloured discs of varying sizes (1 mm to 40 mm) with a black handle, which the clinician moved over the tangent (Bjerrum) screen to locate and plot vision losses in the central visual field. Done properly the clinician wore a black glove and black gown to minimise distraction. Frank Juler, an English ophthalmologist, developed this device to project the target on to the tangent screen. He first published the device in 1939 (BMJ 1939; 23(4): 239-242) but the commencement of World War 2 in 1939 caused its production to be suspended. It was modified and brought back into production in 1950 (Brit J Ophthal 1951; 34: 246-247). This was not an entirely new idea. It was designed to be either hand-held or mounted on a stand so the clinicians had both hands free to record the results.It was not commonly used by Australian optometrists who although aware of the importance of measuring visual fields and the value of tangent (Bjerrum) screen testing did not commonly set themselves up to do it, and did not often do it even if they had the equipment. Those that did continued to use Traquair targets (Cat No 1302 and 3485).
How Acquired: Donated by Kevin Rooney
Date Acquired: Oct 2017
Condition: Good. Electrical cord not original
Location: Museum gallery