Visual accommodation is the
of varying the curvature
the crystalline lens to possible the
variation of refractivity to adjust the
of objects exactly onto
retina. The visual accommodation
accomplished by the action the ciliary
muscles.

The vision depends on the
accommodation since, if the are
not projected onto retina but in
front behind it, they will
blurred. The closer an is more
the ciliary must compress the
crystalline (increasing its
curvature); the distant an object
is the ciliary muscles must .