1. PHARMACY TECHNICIAN
CHAPTER TWENTY TWO

2. Anatomy of the Eye
Cornea—clear or transparent outer “window” of the eye
Sclera—opaque, white portion around the circumference of the cornea
Conjunctiva—thin, transparent layer that extends from the edge of the cornea to cover the sclera; also lines the inside of the eyelids

3. Anatomy of the Eye (cont.)
Iris—colored disc visible through the cornea
Pupil—opening in the iris
Lens (crystalline lens)—located directly behind the iris
Retina—sensory tissue that lines the back of the eye
Optic nerve—visual pathway by which electrical impulses move from the retina to the brain and back
Macula—small, yellowish area in the retina that provides the most central and acute vision

4. Anatomy of the Eye (cont.)
Vitreous humor—occupies about 80 percent of the interior of the eye; composed mostly of water
Choroid—layer of nourishing blood vessels between the sclera and the retina
Extraocular muscles—regulate the motion of each eye

5. Anatomy of the Ear
The outer ear structures are the visible portion of the ear
The middle ear structures include:
Tympanic membrane (eardrum)
Auditory canal
Malleus, incus,
and stapes
Eustachian tube

6. Anatomy of the Ear (cont.)
The inner ear structures include:
Cochlea, snail-shaped organ that contains the nerves required for hearing
Vestibular labyrinth, which contains the sense organs required for balance

7. Function of the Eye The function of the eye is sight
In humans, stereoscopic vision creates depth perception

8. Functions of the Ears
The ears have two separate functions: to hear and to govern balance
These functions are not interdependent
One may be deaf and have perfect balance
One may have perfect hearing and have a disrupted sense of balance

9. Common Diseases of the Eyes
Stye (hordeolum)—localized infection of the sebaceous gland in a hair follicle at the base of an eyelash
Blepharitis—inflammation of the eyelid margins, accompanied by redness, thickening, and possibly the formation of scales and crusts or shallow marginal ulcers
Conjunctivitis—acute or chronic inflammation of the conjunctiva caused by a virus, bacteria, allergy, or irritant such as wind, smoke, or snow
Vascular retinopathy—noninflammatory disease in which the retina has become damaged

10. Bacterial conjunctivitis.
Figure 22.3
Bacterial conjunctivitis.
(Phototake NYC.)

11. Diseases of the Ears
Otitis media—an inflammation and infection of the middle ear
Hearing loss—technically not a disease; there are many types of hearing loss
Earwax buildup—also not a disease; this condition can lead to temporary hearing loss, loss of homeostasis, and irritation of the ear