THE EYE 



The eyeball is almost spherical. It consists of the segments of 

 two spheres, namely, a large posterior or sclerotic segment, which 

 is opaque, and a small anterior or corneal segment, which is trans- 

 parent. The sclerotic segment forms five-sixths of the eyeball, 

 and the corneal segment forms one-sixth. The centre of the 



Levator Palpebrae Superioris 



Hyaloid Canal ' 



(Canal of Stilling) 



Canal of Schlemm 



Hyaloid Membirne 

 Retina 



. Choroid 



Rectus Superior 



^.Sclerotic 



Arteria_ 

 ; /Centralis 

 /•• / Retinae 



Let 



Iris' 

 Ciliary , i> 

 Processes M 



Canal of Petit 



Rectus Inferior 



Fornix Conjunctivse 



Fig. 625. — Vertical Sagittal Section of the Eye and its 

 Appendages (Hirschfeld and Leveill£). 



corneal segment is called the anterior pole, and the centre of the 

 sclerotic segment is known as the posterior pole. The sagittal 

 (antero-posterior) axis, or axis of vision, of the eyeball is repre- 

 sented by a line connecting the anterior and posterior poles. The 

 equator is represented by a line encircling the eyeball opposite 

 the centre of the axis of vision, the diameter of the circle being 



1506 



