Visual System, Diseases, and Impacts

Question 1

Oculomotor System

Answer 1

Made up of many brain areas that cooperate to stabilize images of interest on the high-acuity part of the retina

Question 2

Sclera

Answer 2

Tough white outer layer of the eyeball

Provides protection and form

Question 3

Cornea

Answer 3

Avascular clear front portion of the outer layer

Lets light rays enter the eyes and converges the light rays

Question 4

Iris

Answer 4

Colored part of the eye
Behind cornea and in front of lens
Controls the amount of light entering the eyes

Question 5

Ciliary Body

Answer 5

Portion of the uveal tract between choroid and iris

Ciliary muscle alters the power of the lens

Question 6

Choroid

Answer 6

Layer between sclera and retina

Supplies blood to the retina

Question 7

Retina

Answer 7

Inner sensory nerve layer next to the choroid that lines the posterior two thirds of the eye
Reacts to light and transmits impulses to the brain

Question 8

Lens

Answer 8

Transparent biconvex structure behind the pupil

Helps bring light rays to focus on the retina

Question 9

Optic Nerve

Answer 9

Cranial nerve extending from the optic disk to the optic chiasm
Carries electrical impulses from the retina to the optic chiasm in the brain

Question 10

Vitreous Cavity

Answer 10

Space between the retina and optic nerve posteriorly and between the lens and the ciliary body anteriorly
Hold vitreous that helps maintain the shape of the eye

Question 11

Macula

Answer 11

Functional center of the retina

Gives us the ability to see 20/20 and best color vision

Question 12

Fovea

Answer 12

Responsible for central vision

Located at the center of the retina

Question 13

Uveal Tract

Answer 13

Layer of tissue that runs between the cornea and sclera on the outside and the retina on the inside of the eye.
Made up of Irish, Choroid, and Ciliary Body

Question 14

Optic Chiasm

Answer 14

Junction where fibers coming from the nasal portion of the retina of each eye split off from their optic nerves and cross over to the opposite side to join with fibers coming from the temporal portion of each retina from the opposite side

Question 15

Optic Pathway to the brain

Answer 15

includes the retina, optic nerve, optic chiasm, optic radiations, and occipital cortex

Question 16

Amblyopia

Answer 16

Reduction in visual acuity because of nonuse of that eye or marked differences in refractive errors of the two eyes.

Central vision loss

Question 17

Nystagmus

Answer 17

Involuntary, rhymical. repeated movement of one or both eyes in a horizontal, vertical, or circular pattern.
Low visual acuity is caused by inability to maintain steady fixation of the gaze, most people perceive objects as being stationary

Causes central vision loss

Question 18

Myopia

Answer 18

Means near sighted. There is a convergence insufficiency

Caused by an increase in eye length

Question 19

Hyperopia

Answer 19

Farsighted
Eyes are shorter then the average length
Light rays converge behind the retina

Question 20

Keratoconus

Answer 20

Extreme corneal curvature defect that results in the cornea becoming increasingly cone shaped

Central vision loss

Question 21

Presbyopia

Answer 21

Lens becomes less flexible and less able than previously to accommodate for near point viewing. “arms aren’t long enough”

Presbyopia is a natural part of aging process and usually begins around age 40.

Question 22

Cataracts

Answer 22

Formed when the lens of the eye becomes opaque.

Cataracts are a normal part of the aging process

Question 23

Diabetic Retinopathy

Answer 23

When vitreous starts to pull away from the retina and vessels hemorrhage

Can effect both central and peripheral visual acuity

Question 24

Macular Degeneration

Answer 24

Can be wet or dry; dry is more common
Dry is when a greater number of cone cells die
Can cause visual hallucinations and is a central vision loss

Question 25

Central Scotomas

Answer 25

Areas of diminished or absent vision that result in a “blind spot” in the center of the visual field.

Affect acuity and color vision

Question 26

Glaucoma

Answer 26

Condition in which intraocular pressure becomes sufficiently high to damage the nerves of the retina and optic nerve

Causes peripheral field loss

Question 27

Retinitis Pigmentosa

Answer 27

Group of diseases that result in degeneration of the retina.

Causes peripheral loss

Question 28

Homonymous Hemianopsia

Answer 28

Also called half vision. Results when a specific portion of the optic pathway malfunctions.

Loss of half the central field and entire peripheral field in the opposite eye. Only see one side in each eye.

Left brain injury = loss in right half of vision

Question 29

Cortical Vision Loss

Answer 29

Result of damage to one or both occipital lobes

Question 30

CVA

Answer 30

Cerebrovascular accident, also known as a stoke

CVA is most likely to cause Homonymous Hemianopsia

Question 31

Normal lens changes with age

Answer 31

Lens hardens and become less flixible
Lens thickens
Lens becomes more yellow and absorbs more light

Question 32

Normal pupil changes with age

Answer 32

Pupil size decreases

Question 33

Normal changes light/dark adaptation with age

Answer 33

More sensitive to light
Harder time adapting to dark environments
Harder time adapting from dark to light or vice versa