vision

Question 1

The eye is protected by

Answer 1

Bones of the skull that make up the orbit (eye socket)
2. Eyelids and Eyelashes – keep debris out of the eye
3. Tears – secreted from the lacrimal gland
- Cleanse the surface of the eye
- Prevent the surface of the eye from drying out
- Have antibacterial properties

Question 2

outer layer: sclera

Answer 2

Sclera = connective tissue surrounding the eye. Forms
the whites of the eye

Question 3

middle layer: Choroid

Answer 3

Choroid = pigmented layer between sclera and retina that contains blood vessels (provide nutrients/O2 to retinal cells). Is continuous with the…

Question 4

middle layer: Ciliary body

Answer 4

Ciliary body = connects choroid to iris. Has suspensory ligaments
and smooth muscle that control the shape of the lens.

Question 5

middle layer: iris

Answer 5

Iris = visible pigmented portion of the eye (eye colour). Contains smooth muscles for pupil constriction and dilation. These muscles are controlled by the autonomic nervous system.

Question 6

outer layer: Cornea

Answer 6

Cornea = most anterior part of the eye. Clear transparent layer that light can pass through. If you wear contact lenses, they sit on the cornea.

Question 7

inner layer: retina

Answer 7

Outer pigment cell layer – dark green colour. Absorbs excess light so that it does not reflect back into eye

Photoreceptor layer – 2 types of photoreceptors that transduce light energy into electrical and chemical
signals

Question 8

inner layer: rods

Answer 8

More abundant photoreceptor type

• grey scale/night vision
  -Low acuity (detects sizes, shapes, brightness) more convergence

located: peripheral retina

Question 9

inner layer: cones

Answer 9

less abundant
colour/day vision- less convergence

located: fovea

Question 10

Anterior compartment

Answer 10

between cornea and lens

• filled with aqueous humor (has similar composition to extracellular fluids)

Question 11

Posterior compartment

Answer 11

between lens and retina

• filled with vitreous humor (gelatinous substance
  produced by the ciliary body)
  Choroid

Question 12

lens, pupil and fovea

Answer 12

bends light to focus it on the retina

opening in the iris that allow light to enter the posterior compartment of the eye.

area of the retina onto which most light entering the eye is focused

Question 13

Myopia

Answer 13

near sightedness
(Difficulty seeing distant objects, but near objects are clear).

Focal point falls in front of the retina instead of directly on the retina
because eye is longer than normal or the cornea is curved too much.

Question 14

Hyperopia

Answer 14

far sightedness

(Difficulty seeing near objects, but distant objects are clear).

Focal point falls in behind the retina instead of directly on the retina
because eye is shorter than normal or cornea is curved too little

Question 15

Astigmatism

Answer 15

flaws in curvature of cornea or lens causes some rays of light to scatter and not hit the fovea , resulting in blurred vision.