Porth's Essentials of Pathophysiology, 4e

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Nervous System

U N I T 1 0

A

B

C

D

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.)

Disorders of the Conjunctiva and Cornea

(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

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

Retina

Choroid

Sclera

Superior rectus

Bulbar and palpebral conjunctiva Superior tarsal plate

Levator palpebrae superioris

Lens Cornea

Iris Meibomian gland in tarsal plate Orbicularis oculi muscle Ciliary body

Optic nerve

Inferior rectus

Inferior oblique muscle

FIGURE 38-2. The eye and its appendages: lateral view.