THE EYE 



ciliary body, and it may 

 be approximately indi- 

 cated by a parallel circle 

 midway between the 

 margin of the cornea 

 and the equator of the 

 eyeball. The anterior 

 segment contains the 

 cornea, the sclero-cor- 

 neal junction, the an- 

 terior and posterior 

 chambers, the aqueous 

 humor, the iris, and 

 the ciliary body. The 

 posterior segment com- 

 prises the posterior two- 

 thirds of the eyeball and 

 includes the sclera, cho- 

 roid, retina, and, within 

 these coats, the vitreous 

 humor. The crystalline 

 lens with its suspensory 

 ligament forms, as it 

 were, a partition sepa- 

 rating the two segments. 

 The optical or visual 

 axis of the eye is a hori- 

 zontal, antero-posterior, 

 imaginary line which 

 extends from the center 

 of the cornea through 

 the center of the ante- 

 rior chamber, the center 

 of the pupillary opening 

 of the iris, the center 

 of the crystalline lens, 

 and the center of the 



FIG. 417. THE ANTERIOR SEGMENT OF A CHILD'S EYE; MERIDIONAL SECTION. 

 a, ora serrata ; 6, ciliary processes ; c, iris ; d, crystalline lens ; <?, ciliary muscle ; /, oc- 

 ular conjunctiva ; g, cornea ; h, the capsule of the lens, partially detached. Heruatein 

 and eosin. Photo, x 10. 



