THE EYE A 'CAMERA' 



multiply the image. Lastly, the whole apparatus can be set to take 

 equally sharp pictures at different distances (accommodation = substi- 

 tuting one lens for another in the camera, or varying distance between 

 lens and film). 



posterior chamber 

 limbal zone. 



conjunctiva 

 canal of Sc hie mm 

 ciliary muscle 



sclera 

 chorioid' 



lamina cribrosa 



Fig. 3 — Horizontal section of right human eye. x 4. Modified from Salzmann. 



On the left, the section contains a cihary process behind which the zonule fibers are partly 

 concealed; on the right, the section has passed between two ciliary processes and the full 

 extent of the zonule fibers can be seen. The limbal zone (transition between cornea and 

 sclera) is stippled to emphasize that it is broader internally than externally. 



The Fibrous Tunic — The outer case of the living camera is formed 

 by the fibrous tunic, consisting of the sclera and the cornea, the latter 

 seemingly a transparent anterior continuation of the sclerotic coat which 



