Text-book of ophthalmology . the contraction of these fibers the flat portion of the ciliary body andthe most anterior portion of the chorioid are drawn forward, and thus the 852 TEXT-BOOK OF OPHTHALMOLOGY relaxation of the fibers of the zonula which lie upon the surface of thesestructures is facilitated; but the main part of the work of accommodationalways falls upon the annular fibers of the ciliary muscle, for which reasonwe find these fibers particularly well developed in eyes which have toaccommodate a good deal—e. g., those of hypermetropes (see Fig. 384). By the relaxation of
Text-book of ophthalmology . the contraction of these fibers the flat portion of the ciliary body andthe most anterior portion of the chorioid are drawn forward, and thus the 852 TEXT-BOOK OF OPHTHALMOLOGY relaxation of the fibers of the zonula which lie upon the surface of thesestructures is facilitated; but the main part of the work of accommodationalways falls upon the annular fibers of the ciliary muscle, for which reasonwe find these fibers particularly well developed in eyes which have toaccommodate a good deal—e. g., those of hypermetropes (see Fig. 384). By the relaxation of the zonula the tension of the lens capsule isdiminished, so that the lens is enabled in conformity with its elasticity toassume a more curved shape. At the same time there is necessarily pro-duced a corresponding decrease in the equatorial diameter of the equator of the lens, accordingly, recedes inward toward the axis ofthe eye, and is thus kept from coming into contact with the ciliary processesas they Fig. 371.—Schematic Representation of the Process of relation of the parts when the accommodation is at rest is designated by the shaded por-tions, and the relation when there is an effort of accommodation, by the thick black lines In thedrawing it looks as if the zonula fibers were running through the ciliary process. In reality the fibers ofthe zonula for the most part lie in the depressions between the ciliary processes, and hence xun to thelateral slopes of the ciliary process that is represented in the drawing. With these slopes they areconnected by numerous fibers and hence, when the ciliary processes advance toward the sagittal axisof the eye, the zonula fibers are taken along with them and are likewise pushed inwards; and to a cor-responding amount the equator of the Ions recedes toward the sagittal axis of the eve Both (surfacesof the Lens become more curved and the anterior surface is advanced. The iris is broader and at itspu
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