The home medical adviser, a popular work on the treatment of disease . -—-b Fig. 68.—Farsighted (Hyperopic) Eye Showing the Focusing of Rays from Near(n) and Far Objects (h) Behind the Retina. about one-third of an inch thick, which looks very much like an ordi-nary glass lens, and is situated in the eye just back of the pupil. Thisis what is known as the crystalline lens, and the rays of light are bent CORNEA. CONJUNCTIVAANTERIORCHAMBER CILIARYMUSCLE RETINA OPTIC NERVE Fig. 69.—During Accommodation the Lens Becomes More Convex Through Con-traction of the Ciliary Muscle, as Shown in the Left o
The home medical adviser, a popular work on the treatment of disease . -—-b Fig. 68.—Farsighted (Hyperopic) Eye Showing the Focusing of Rays from Near(n) and Far Objects (h) Behind the Retina. about one-third of an inch thick, which looks very much like an ordi-nary glass lens, and is situated in the eye just back of the pupil. Thisis what is known as the crystalline lens, and the rays of light are bent CORNEA. CONJUNCTIVAANTERIORCHAMBER CILIARYMUSCLE RETINA OPTIC NERVE Fig. 69.—During Accommodation the Lens Becomes More Convex Through Con-traction of the Ciliary Muscle, as Shown in the Left of the Diagram, whileto the Right of the Line Drawn Through the Eye is Shown the Position ofthe Lens at Rest. in passing through it so as to be properly focused on the retina (SeeFig. 69). The foregoing statements have been made as though objects werealways at a distance from the eye, so that the rays of light coming DISEASES OF THE EYE 695 from them were almost parallel. Yet when one is looking at anobject within a few inches of the eye the rays diverge or spread out,and these the normal eye (if rigid) could not focus on the retina—much less the farsighted eye. But the eye is adaptable to change offocus, through the action of the ciliary muscle which controls to a con-siderable extent the shape of the lens, and is situated within the eye-ball surrounding the lens. When the ciliary muscle contracts i
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