Physiology

Question 1

what is hypermetropia

Answer 1

long sightedness

- can see objects clearly at a distance but struggle focus on things up close

Question 2

what type of lens is needed to correct hypermetropia

Answer 2

converging lens

- eye needs the light to come closer (converge) before it hits the retina

Question 3

what is myopia

Answer 3

short sightedness

- can see objects clearly up close but struggle to focus on things at a distance

Question 4

what type of lens is needed to correct myopia

Answer 4

diverging lens

- eye needs light to move apart (diverge) before it hits the retina

Question 5

what is presbyopia

Answer 5

eye’s reduced ability to focus on near objects because of age

Question 6

the ophthalmic artery is a branch of what artery

Answer 6

internal carotid

Question 7

what are the chambers of the eye?

what fluid is contained in each?

Answer 7

anterior chamber (between cornea + iris) - aqueous humour 
posterior chamber (between lens + iris) - aqueous humour
vitreous chamber - vitreous humour

Question 8

what structure produces aqueous humour

Answer 8

ciliary body

Question 9

what structure drains the aqueous humour

Answer 9

trabecular meshwork into canal of Schlemm

Question 10

what is the function of the ciliary muscles

Answer 10

control the refractive shape of the lens – accommodation

Question 11

what nerve innervates the ciliary muscles

Answer 11

CN III

- parasympathetic stimulation causes muscle contraction – flattens lens to allow near vision

Question 12

what nervous system division causes pupil constriction

Answer 12

parasympathetic

Question 13

what nervous system division causes pupil dilation

Answer 13

sympathetic via

Question 14

what effect will pilocarpine have on the pupil

Answer 14

pilocarpine is a miotic drug – pupil constriction

Question 15

what effect will topicamide or atropine have on the pupil

Answer 15

mydriatic drugs – pupil dilation

Question 16

sensory supply to cornea

Answer 16

CN V(1) - 1st division of trigeminal

Question 17

blink reflex:

• afferent limb
• efferent limb

Answer 17

afferent limb = CN V(1)

efferent limb = CN VII

Question 18

light reflex:

• afferent limb
• efferent limb

Answer 18

afferent = optic nerve 
efferent = oculomotor

Question 19

name the extra-ocular eye muscles

Answer 19

medial rectus 
lateral rectus 
inferior rectus 
superior rectus 
inferior oblique 
superior oblique

Question 20

nerve supply to extra-ocular eye muscles

Answer 20

LR6 SO4 AO3
Lateral rectus = CN 6 (abducens)
Superior oblique = CN 4 (trochlear)
All others = CN 3 (oculomotor)

Question 21

function of superior oblique

Answer 21

moves eye down + out

Question 22

function of inferior oblique

Answer 22

moves eye up + out

Question 23

symptoms of a 3rd nerve palsy

Answer 23

eye is down + out, ptosis, pupil dilated

Question 24

symptoms of 4th nerve palsy

Answer 24

head tilt

congenital palsy

Question 25

symptoms of 6th nerve palsy

Answer 25

horizontal diplopia

failure to abduct affected eye