Eye and Vision Lecture

Question 1

Vision is

Answer 1

used for sight and balance/equilibrium

Question 2

Anatomy of the Eye

Answer 2

1. Fibrous Layer : outermost layer
   a) SCLERA; white in color + made up of tough C.T attaches to eye muscle
   b) CORNEA: transparent layer
   - avascular
   - involved with the refraction of light “focus”
   ex: uneven curvature to the lens/cornea = astigmatism
2. Vascular Layer: middle coat/layer
   a) CHOROID coat; loaded w/capillaries, heavily pigmented (black in color) + provides blood flow to the retina
   b) CILIARY BODY; produces substance aqueous humor (fluid produced daily) to nutrient the lens/cornea
   - has suspensory ligaments attached to the lens by pulling on the lens and changing the shape of the lens
   c) IRIS; colored part, made up of 2 layers of smooth muscle, function is to change pupil size
   - Radial Fibers (outermost)
   - Circular Fibers (under the radial layer)
3. Inner Layer
   a) RETINA; contains photo-receptors (sense light)
   - contains Rods (for dim light) NEEDS Vit.A
   - Cones (for colors and bright lights)
   – retina is held in place by a gel called, vitreous humor
   - fovea centralis has lots of cones = acute vision
   - optic disc has no rods or cones = blind spot

Question 3

What is a “pink eye”

Answer 3

aka conjunctivitis
- is the inflammation of the conjuctiva which is a thin layer on top of the sclera

Question 4

Issues with the Ciliary Body

Answer 4

If the drainage of aqueous humor is blocked…
- increases intraocular pressure; causes compression of retina and the optic nerve causing Glaucoma (untreated = blindness)
- can be treated by eye drops

Question 5

Issues with the Retina

Answer 5

• Macular Degeneration: a loss of cone/rod cell in the retina; progressive disease
• Retinal Detachment: occurring in the vitreous humor, it gets between the retina and choroid coat. Denying blood into the retina caused by trauma to eye leading to blindness
• Cataracts: opaque areas on the lens occurring within aging
  treated with a layer or replacement of the lens

Question 6

Process of Focusing

Answer 6

Focusing light rays on the retina to “accommodation” which is the change of shape in the lens

Question 7

Vision Problems:

Answer 7

1. Nearsightedness: eyeball is too long
2. Farsightedness: eyeball is too short
3. Presbyopia: lack of elasticity
   - reading glasses around 50ish years of age

Question 8

Process of Vision

Answer 8

1. Refraction (bending) of the light rays: done by the cornea/lens
   - Accommodation of lens
2. Constrict/dilate pupils
3. Convergence; both eyeballs looking at the SAME object
4. Start A.P; optic nerve has been activated > optic chiasma > optic tract > occipital lobe of the cerebrum