Examination of the central visual field at a reading distance.

THIS investigation was started in an attempt to produce a simple, self-recording method of examining the central visual field that is readily performed at a reading distance, for example at the bedside or desk. A specially-designed chart incorporating a grid system, a pen, and a good light are the only necessary items of equipment. The use of a grid is based on the chart described by Amsler (1953) for the detection of early disturbances within the macular area which appear as a distortion of vertical or horizontal lines. The area covered by the Amsler Chart is a square subtending an angle of 200, 10° to the right, to the left, above, and below the fixation point, when held 30 cm. from the eye. Small as this area is, scotomata near the macula may be apparent. It was felt that this form of static perimetry could be modified for the plotting of central visual field defects. The following factors were taken into consideration whilst designing the chart.