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ophthal:\iology for veterinarians 



Fields. — When the eyes are fixed upon some object 

 directly in front of them, objects at the left are noticed 

 by the right half of the retina of each eye, while those at 

 the right are noticed by the left half of the retina of each 

 eye; those above by the lower half, and those below by 



Fig. 44. — Diagram illustrating the visual path and its relation to the 

 visual field, left lateral hemianopsia being shown (Seguin). 



the upper half. These are called the fields of vision, and 

 they vary greatly in animals of different kinds. They 

 are influenced by the position of the eyeballs, the promi- 

 nence of the orbital ridges, the distance between the 

 eyes, and the structure of the face. In man, because of 

 his requirements, the fields are probably greater than in 



