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a) Accommodation of distant object (far vision)
The ciliary muscles relax; the suspensory ligaments contract and pulled tight ;the lens then becomes (thinner); light from
distant object is less refracted the focused on the fovea; and then interpreted in the brain;
Accommodation of a close object (near vision)
The ciliary muscle contract; the suspensory ligaments relax; the lens then become thicker (more spherical); light from
close object is greatly refracted and focused on the fovea; and then interpreted in the brain;
b) Light enters the eye through the pupil; the radial and circular muscles in the iris control the size of the pupil,
depending upon light intensity ;the muscles work antagonistically.
In bright light (high light intensity) ;the amount of light entering the eye should be low; hence the pupil should be
narrow; radial muscles of the iris relax; the circular muscles contract ; the pupils becomes smaller; while the iris enlarges
thus less light enters the eye;
In dim light/ low light intensity; radial muscles in the iris contract; the inner circular muscles relax; the iris becomes
smaller while pupil enlarges more light enters to the eye;
gregorymasila answered the question on February 23, 2018 at 12:01
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