Projection scotometer of Juler

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).