14 



THE EYE. 



EPITHELIUM 

 CONJUNCTIVA" 



MUSCULUS 

 CILIARISv 



ARTERIA 



CENTRALIS 



RETIN/E 



Fig. 15. DIAGRAM OP THE RIGHT ADULT HUMAN EYE, DIVIDED NEARLY HORIZONTALLY THROUGH THE 



MIDDLE. (E. A. S.) Magnified five times. 

 The line a b passes through the equator, x y through the visual axis of the eye. 



The figure has been drawn, as far as possible, to scale, the following being taken as the 

 average measurements of the parts of the adult eye in millimeters : 



Transverse diameter of the eyeball 24'5 



Vertical diameter . . . . . . . . . ... . 23'5 



Antero -posterior diameter ........... 24'0 



Greatest thickness of the sclerotic, choroid, and retina together . . . . 1*4 



Greatest thickness of the sclerotic posteriorly . . . . . .0*8 



Thickness of the sclerotic at the equator 0'4 



Thickness of the cornea in the centre ......... 0*8 



Distance from the middle of the anterior surface of the cornea to the front 



of the lens 3*4 



Antero-posterior diameter of the lens 4'0' 



