THE SYMPATHETIC SYSTEM 



193 



side of both retina. It results in a bilateral hemianopsia, 

 a frequent symptom of great diagnostic importance and 

 which often precedes amaurosis. The visual disturbance 

 at first may only be for colors and is a hemidyschroma- 

 topsia. The hemiopic reaction of Wernicke; that is, the 



Temporal and nasal side 

 of the visual field 



00 



temp 

 retina 



> 



fa 

 t 



PITUITARY 

 PROTRUSION 



PROJECTION OFTHE PINEAL 



8 pre'chiasmic lesion 



b chiasmi c lesion 



c retrochiasmic lesion 



f.n: nasal fibres temporal fibres 



8. optic SHEET. f the P tic nerve 



FIG. 16. 



absence of the pupillary reflex to light in that part corres- 

 ponding to the visual field, is also an important symptom,, 

 but difficult to bring out. 



More rarely the hemianopsia is temporal, unilateral, 

 when the other eye is already amaurotic. 



(c) A retro-chiasmic lesion causes a bilateral 

 homonymous hemianopsia. Lesions in the fundi are 

 nearly as frequent as modifications of the visual field. 



13 



