Fig. 5. A. Three dimensional model of Traquair's “Island of Vision.” The visual field of the right eye is shown. B. Standard flat plot of isopters, as if viewed from above. C. Vertical cross-section along horizontal meridian. O, target size in mm; D, distance from eye in mm; VA, visual angle. (From Scott GI: Traquair's Clinical Perimetry. London: Henry Kimpton, 1957)