Page 1925 - Saunders Comprehensive Review For NCLEX-RN

eye, located in front of the lens, and it
has a central circular opening called
the pupil. The pupil controls the
amount of light (darkness produces
dilation and light produces
constriction) admitted into the retina.

3. Internal layer

a. Consists of the retina, a thin, delicate
structure in which the fibers of the
optic nerve are distributed.
b. The retina is bordered externally by the
choroid and sclera and internally by
the vitreous.
c. The retina is the visual receptive layer
of the eye in which light waves are
changed into nerve impulses; it
contains blood vessels and
photoreceptors called rods and cones.
C. Vitreous body
1. Contains a gelatinous substance that occupies the
vitreous chamber, the space between the lens and the
retina
2. The vitreous body transmits light and gives shape to
the posterior eye.
D. Vitreous
1. Gel-like substance that maintains the shape of the eye
2. Provides additional physical support to the retina
E. Rods and cones
1. Rods are responsible for peripheral vision and
function at reduced levels of illumination.
2. Cones function at bright levels of illumination and are
responsible for color vision and central vision.
F. Optic disc
1. It is a creamy pink to white depressed area in the
retina.
2. The optic nerve enters and exits the eyeball at this
area.

3. This area is called the blind spot because it

contains only nerve fibers, lacks photoreceptor cells,
and is insensitive to light.
G. Macula lutea
1. Small, oval, yellowish-pink area located laterally and
temporally to the optic disc

2. The central depressed part of the macula is the

1925