Class notes eyes

Question 1

What protects the eye?

Answer 1

Bony orbital cavity

Additional protection from—eyelids (injury, strong light, dust); and lacrimal apparatus

Question 2

What kind of vision do humans have?

Answer 2

Human have a binocular, single-image visual system

Question 3

Extraocular muscles (EOMs) movements:

Answer 3

straight and rotary movement

conjugate movement—parallel axis of movement in both eyes

Question 4

Movement of EOMs stimulated by three cranial nerves:

Answer 4

CN VI (abducens)
CN IV (trochlear)
CN III (oculomotor)

Question 5

3 layers of eye:

Answer 5

Sclera; choroid; retina

Question 6

outer layer of eye:

Answer 6

sclera

Question 7

Sclera characteristics:

Answer 7

tough protective white covering
Continues anteriorly as smooth
transparent cornea

Question 8

Cornea does:

Answer 8

refracting medium—bends light rays to focus on retina

Question 9

Corneal reflex:

Answer 9

stimulation of cornea causes blinking

Question 10

Nerves for blinking:

Answer 10

CN V (trigeminal)—afferent sensation to brain
CN VII (facial)—efferent message-stimulates blinking

Question 11

Middle layer of eye:

Answer 11

Choroid

Question 12

Choroid characteristics:

Answer 12

Darkly pigmented
Continuous anteriorly with iris
Highly vascularized—delivers blood to retina

Question 13

Iris:

Answer 13

Controls amount of light admitted to retina

Question 14

Iris bright/dark light:

Answer 14

In bright light—the eye contracts and accommodates for near vision
In dim light—the eye dilates and accommodates for far vision

Question 15

Pupil size reacts to:

Answer 15

Amount of ambient light and accommodation

Question 16

Pupil is:

Answer 16

round, regular

Question 17

Parasympathetic and sympathetic nervous system determines what in pupil:

Answer 17

Size

Question 18

Stimulation of parasympathetic—through CN III causes pupil to:

Answer 18

pupil constricts

Question 19

Stimulation of sympathetic pupil:

Answer 19

pupil dilates, eyelid elevates

Question 20

Lens of eye is:

Answer 20

biconvex disc posterior to pupil
Serves as refractory medium—bulges for focusing on near objects
flattens for far objects

Question 21

Inner layer of eye:

Answer 21

Retina

Question 22

Retina function:

Answer 22

light waves changed into nerve impulses

Question 23

Retinal structures viewed with ophthalmoscope:

Answer 23

Viewed: optic disc; retinal vessels; general background; macula

Question 24

What determined by balance between amount of aqueous humor produced and resistance to outflow at angle of the anterior chamber?

Answer 24

Intraocular pressure

Question 25

What does the aqueous humor do?

Answer 25

Nourishing the cornea and the lens by supplying nutrition such as amino acids and glucose Maintain intraocular pressure. Transport Vitamin C in the front segment to act as an anti-oxidant agent.

Question 26

Pupillary Light Reflex tests which nerves?

Answer 26

``` CN II (optic)—sensory afferent link CN III (oculomotor)—motor efferent path ```

Question 27

With different light reflex, what occurs?

Answer 27

consensual light reflex occurs

Question 28

What is accommodation?

Answer 28

adaptation of the eye for near vision; convergence of axes of the eyes when changing focus from far vision to near vision

Question 29

Examine for accommodation?

Answer 29

focus on distant object (pupils dilate) and then shift gaze to near object (Such as finger) caused pupillary constriction and convergence

Question 30

When does macula Macula mature?

Answer 30

absent at birth; mature by 8 mo.

Question 31

Eye movements in infant:

Answer 31

poorly coordinated

Question 32

binocularity established at what age in infants?

Answer 32

3-4 months

Question 33

% of infants born with farsightedness:

Answer 33

80%

Question 34

When does farsightedness decrease in children?

Answer 34

this decreases by age 7-8

Question 35

What happens to lens in aging adults?

Answer 35

Lens loses elasticity—becomes hard and glass-like

Question 36

Increase or decreased ability to change shape to accommodate for near vision in aging adult?

Answer 36

decreased

Question 37

What age does 50% of aging adults develop presbyopia (farsightedness)?

Answer 37

By age 40 | So may need images magnified

Question 38

What age does normally transparent fibers of lens begin to thicken and yellow?

Answer 38

By age 70 | Cataracts

Question 39

What is arcus senilis?

Answer 39

Narrow opaque band encircling cornea | Common in old age

Question 40

Most common causes of decreased visual functioning?

Answer 40

Cataract formation Glaucoma Age-related macular degeneration (AMD) Diabetic retinopathy

Question 41

Age-related macular degeneration (AMD) is?

Answer 41

Yellow deposits & neovascularity in macula; loss of central vision

Question 42

Optic nerve neuropathy; loss of peripheral vision caused by ↑IOP is called?

Answer 42

Glaucoma

Question 43

What do you ask about eyes for sub data:

Answer 43

``` Vision changes; pain Ask about acute onset of floaters, halos around lights, loss of peripheral vision, blind spot ```

Question 44

What is Strabismus?

Answer 44

misalignment of eyes, inward or outward

Question 45

What is diplopia?

Answer 45

double vision

Question 46

Ask about these things in eye sub data:

Answer 46

Redness, swelling—one or both eyes, watering, discharge

Question 47

Ask about vaginal infections in mother at time of delivery such as:

Answer 47

genital herpes, GC lead to risk for eye disease in the newborn

Question 48

test for visual acuity:

Answer 48

Snellen eye chart | 20 feet away

Question 49

Vision parameters:

Answer 49

Normal visual acuity—20/20 Poor than 20/30—refer to eye provider impaired vision: 20/50

Question 50

Vision impairment due to:

Answer 50

Refractive error Opacity in the media (cornea, lens, vitreous) Disorders in the retina or optic pathway

Question 51

Visual field test is testing for:

Answer 51

Testing for peripheral vision loss | In older adult—screen for glaucoma

Question 52

Diagnostic Positions Test:

Answer 52

Lead the eyes through six cardinal position of gaze to determine any EOM weakness There should be parallel tracking with both eyes

Question 53

nystagmus

Answer 53

fine oscillating movement (can be seen with ear or eye disease; MS; brain lesions; overdose of phenytoin)

Question 54

3 things to assess in eye:

Answer 54

Check lateral canthus (corner of eyes) for pallor Check sclera for jaundice Check if pupils are equal

Question 55

What is anisocoria? How many have it normally?

Answer 55

Unequal pupil size, 5% have anisocoria normally