1. Eye Anatomy

2. Eye Structure
enclosed and cushioned by fat and walls of bony orbit

3. filled with fluid = humors
composed of
3 layers = tunics
filled with fluid = humors
to maintain shape
lens
for focusing
divides eye into anterior and posterior chambers

4. 3 Layers: Tunics

5. 1. Fibrous Tunic outermost 2 parts sclera “white of the eye” Tough
Anchors muscles

6. 1. Fibrous tunic 2 parts Sclera 2. Cornea “clear window”
lacks blood vessels
easy to transplant
nutrition via diffusion from aqueous humor - fluid behind

7. 2. Vascular Tunic 3 regions middle choroid (coat) vascular pigmented
posterior part
absorbs light and prevents scattering

8. 2. Vascular Tunic 3 regions choroid ciliary body encircles lens
made of smooth muscle - ciliary muscles
controls lens shape

9. 2. Vascular Tunic 3 regions choroid ciliary body
folds secrete aqueous humor - ciliary processes
suspensory ligaments hold lens up

10. 2. Vascular Tunic 3. iris visible colored area contain melanin
amount and distribution = different colors

11. 2. Vascular Tunic
3. iris
made of muscles that control pupil size - regulating light
pupil is hole in center of iris

12. pupillary reflex also responds to interests or emotions
appealing subject matter, problem solving = dilates
boredom or repugnant material = constriction of pupil

13. 3. Sensory tunic = retina 2 layers outer is pigmented to absorb light
inner layer
transparent
photoreceptor neurons (rods and cones)

14. Detached Retina separation of pigmented from transparent
Warning signs include:
seeing many new flashing lights
showers of many floaters
blurred vision
a curtain-like blockage  

15. 3. Sensory tunic = retina optic disc where optic nerve leaves eye
Fovea
optic disc
where optic nerve leaves eye
“blind spot”
off center
optic nerve has blood vessels in center

16. Photoreceptors Rods dim light black and white just outside fovea
peripheral vision

17. Photoreceptors Cones bright light color vision
Optic Disc
concentrated in center fovea centralis

18. nervous flow is opposite (→ = light)
light → ganglion cells → bipolar neurons → photoreceptors→ back up and to optic nerve

19. Chambers and Humors

20. Posterior Chamber with Vitreous Humor
transmits light
supports back surface of lens
supports eye shape
vitreous humor
thick and clear
lasts a lifetime

21. Anterior Chambers with Aqueous Humor
chamber between cornea and lens
formed in ciliary processes
watery
constantly produced and drained via canals of Schlemm

22. Glaucoma
if canals are blocked
unable to drain

25. Glaucoma if canals are blocked unable to drain
= nerve cells gradually destroyed by pressure
treated with drugs

26. Lens

27. Lens
biconvex
transparent
flexible
becomes less elastic with age

28. Cataracts
lens clouding