2. Accessory structures
 Eyebrows
 - facial expressions, prevent
glare and perspiration in eyes
 Eyelids (palpebrae)
 - protect eye
 - allow sleep
 - separated by palpebral fissure
 - medial & lateral commissures
(canthi)
 - contain tarsal plates & tarsal
glands
 Conjunctiva
 - transparent mucous membrane
that secretes film to prevent eye
from drying

3. Tears!

4. The Six Extrinsic Muscles of the Eye
Oblique: Superior and Inferior
Rectus: Lateral and Medial, Superior and Inferior

5. Anatomy of the Eye
 Three layers (Tunics)
– Outer fibrous layer (Tunica Fibrosa)
 Sclera : dense CT
 Cornea : transparent, admits light
– Middle vascular layer (Tunica Vasculosa)
 Choroid : vascular
 Ciliary body : muscular ring around lens
– Secretes aqueous humor
– Supports iris & lens
– Inner layer (Tunica Interna)
 Retina : contains fovea centralis (detailed images)
– Rods (black & white, night vision)
– Cones (color, day vision)
– Optic nerve (not receptors, blind spot)

6. Anatomy of the Eye
Tunica Fibrosa
Tunica Vasculosa
Tunica Interna

7. Optical Components
 Transparent, admit light, refract rays focus images on retina.
– Cornea
 Modified extension of choroid layer
– Pupil
 Round opening in center of iris that allows light in
 Iris controls diameter, para & symp NS
– thin diaphragm composed mostly of connective tissue and
smooth muscle
– Aqueous humor
 Secreted by ciliary body
 Flows from posterior chamber to anterior chamber &reabsorbed
through canal of Schlemm (glaucoma if blocked)
– Lens
 Suspended by suspensory ligament which attaches to ciliary body
– Vitreous humor
 Transparent jelly behind lens

8. Production and Reabsorption of Aqueous Humor
(Canal of Schlemm)

9. Neuronal layer
of Retina

10. Ophthalmic Exam

11. The optic nerves lead to the optic chiasm where
The

some of the fibers in the nerve trunks cross and
some do not.
Visual  The optic tracts then lead to the lateral
Pathway geniculate nuclei of the thalamus . Each
lateral geniculate nucleus actually receives
information from both eyes. The lateral
geniculate nuclei, bring together information from
both eyes.
 Information is then passed on to the visual cortex
in the occipital region of the cortex.

12. Shape Abnormalities
of
the Eyeball

14. THREE LAYERS
CILIARY BODY 1. Fibrous Tunic
SCLERA
LENS
2. Vascular Tunic
ANTERIOR
CHOROID
CHAMBER
Aqueous Humor) VITREOUS
BODY 3. RETINA
Vitreous Humor
OPTIC NERVE
CORNEA
PUPIL
IRIS

15. SUPERIOR RECTUS MUSCLE
LACRIMAL GLAND
IRIS behind transparent CORNE
MEDIAL RECTUS MUSC
LATERAL RECTUS MUSCLE
PUPIL
SCLERA
RIGHT EYE INFERIOR RECTUS MUSCLE NOSE
SUPERIOR & INFERIOR OBLIQUE MUSCLES are not shown