Examination of the Central Portion of the Visual Fields at the Bedside: a Method of Increased Accuracy of Assessment of the Central 30 Degrees Vision on Confrontation.

IN the everyday examination of the visual fields, on the ward or in the clinic, we utilize methods which are simple and relatively effective. The extent of each peripheral field is tested by finger movement, or by a coloured or white-headed pin, and the blind spot and any scotomata are similarly noted by the use of a pin. A more accurate assessment of the central fields, with respect to small scotomata, relative scotomata, depressions of mild intensity, or early quadrantic or hemianopic defect of mild intensity, is made by examination with the Bjerrum screen. It became apparent that, by the use of a specially constructed, yet simple, test object in the form of a pin, examination by confrontation could be made more sensitive and accurate, and that, leaving the requirements of documentation aside, the need of Bjerrum screen examination in diagnosis could often be obviated. A variety of defects was examined: retrobulbar neuritis, tobacco amblyopia, passive oedema of the optic disc (papilloedema), optic nerve compression, chiasmal interference, and mild intensity homonymous quadrantanopia and hemianopia; all results were checked by full, formal examination with the 2-metre screen and the perimeter, and it became apparent that with increasing experience the essential character of the defect could almost always be determined by confrontation. And in addition to scotomatous depression, any quadrantic or hemianopic depression of such mildness as to effect the 1 or 2 mm. isopter only, could be detected by confrontation.