The Value of Perimetry in Brain Lesions
The study of visual fields is one of the most important aids in the diagnosis of lesions of the central nervous system. The time and effort involved is well worth while as negative results are of value in excluding certain conditions.
Although the perimeter was introduced many years ago, before the ophthalmoscope, its greatest use has followed the stimulating work of Cushing and Walker1. They insisted on studies of the visual fields in every case where brain involvement was suspected.
Combined with pupillary changes, muscle paralysis or weakness producing diplopia with retinal lesion, and optic nerve involvement, the study of the visual fields is a valuable adjunct in many lesions in which the eye is directly or indirectly involved.
When the intracranial pathways are involved, the visual fields will indicate the approximate location and extent of involvement, but are not pathognomonic of the disease, although some definite inference can be drawn by progress studies.
Alteration of the visual fields must be considered as only part of the evidence upon which conclusions are based. It is the purpose of this paper to show that in several types of lesions, studies of the visual fields are not only an aid but, combined with encephalography and other neurological studies, are often of value in the diagnosis of certain lesions of the brain.
Perimetry is of value in the following types of cases2:
Cases in which the media is clear and the fundus is normal.
Cases in which ophthalmoscopic evidence is available,. . .