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U N I T 1 0
Nervous System
Disorders of the Conjunctiva
and Cornea
The conjunctiva is a thin layer of mucous membrane that
lines the anterior surface of both eyelids as the palpebral
conjunctiva and folds back over the anterior surface
of the optic globe as the ocular or bulbar conjunctiva
(see Fig. 38-2). The bulbar conjunctiva covers the sclera
or white portion of the eyeball, but not the cornea. The
conjunctiva provides a barrier against foreign objects
and produces lubricating mucus that bathes the eye and
keeps it moist.
The cornea functions as a protective membrane and
transparent window through which light passes as it
A
C
D
B
FIGURE 38-1.
A scene as it might be viewed by a person with
(A)
normal vision,
(B)
age-related
macular degeneration,
(C)
cataract, and
(D)
glaucoma. (Courtesy of the National Eye Institute,
National Institutes of Health.)
Retina
Choroid
Sclera
Superior
rectus
Levator
palpebrae
superioris
Optic
nerve
Inferior
rectus
Inferior
oblique
muscle
Lens
Cornea
Bulbar and
palpebral
conjunctiva
Superior tarsal
plate
Iris
Meibomian
gland in
tarsal plate
Orbicularis
oculi muscle
Ciliary body
FIGURE 38-2.
The eye and its appendages:
lateral view.
