Vision 2

Question 1

what are the roles of intrinsic muscles?

Answer 1

control pupil diameter & helps alter lens curvature to enable us to see near objects

Question 2

what are the roles of extrinsic muscles?

Answer 2

move the eye

Question 3

what are the 6 extrinsic ocular muscles that move the eye?

Answer 3

Medial rectus (MR)
Lateral rectus (LR)
Inferior rectus (IR)
Superior rectus (SR)
Superior Oblique (SO)
Inferior Oblique (IO)

Question 4

what are the actions of MR?

Answer 4

Adduction

Question 5

what are the actions of LR?

Answer 5

Abduction

Question 6

what are the actions of SR?

Answer 6

Elevation
Adduction
Intorsion

Question 7

what are the actions of IR?

Answer 7

Depression
Adduction
Extorsion

Question 8

what are the actions of SO?

Answer 8

Intorsion
Depression
Abduction

Question 9

what are the actions of IO?

Answer 9

Extorsion
Elevation
Abduction

Question 10

what do you look for in right third nerve palsy?

Answer 10

Drooping eyelid

Eye can move only laterally (and slightly down)

Question 11

what do you look for in left forth nerve palsy?

Answer 11

Eye moving up when adducted

Question 12

what do you look for in abducent (6th) nerve palsy?

Answer 12

Eye being adducted

Eye not able to abduct

Question 13

what is Strabismus?

Answer 13

squint-Misalignment of the eyes

Question 14

what are the 2 different types of squint?

Answer 14

Esotropia (manifest convergent squint)

Exotropia (manifest divergent squint)

Question 15

what is ambylyopia?

Answer 15

(lazy eye) where brain supresses the image of one eye leading to poor vision in that eye without any pathology (correctable in early years using eye patches to stimulate the “lazy” eye to work)

Question 16

what is diplopia?

Answer 16

(double vision) – usually occurs in squints occurring as a result of nerve palsies.

Question 17

what is the definition of the visual field?

Answer 17

Everything you see with one eye (including in the periphery)

Question 18

where do the medial nasal fibres cross to opposite side?

Answer 18

optic chiasma

Question 19

the optic tract contains fibres from which part of the eyes?

Answer 19

ALL fibres from the opposite half of the visual field

Question 20

where do the fibres from the optic tract synapse?

Answer 20

LGB of the thalamus

Question 21

where is the primary visual cortex?

Answer 21

occipital lobe

Question 22

What damage do you expect when the optic nerve is damaged?

Answer 22

blindness in one eye

Question 23

What damage do you expect when Optic chiasma disrupted in the middle?

Answer 23

bitemporal hemianopia- lateral vision of both eyes affected

Question 24

What damage do you expect when optic tract is damaged?

Answer 24

contralateral homonymous hemianopia-lateral vision in one eye and medial vision of the other is affected

Question 25

What damage do you expect when optic radiation is damaged?

Answer 25

contralateral homonymous hemianopia-lateral vision in one eye and medial vision of the other is affected

Question 26

what are the 3 Intrinsic eye muscles?

Answer 26

Ciliaris muscle in ciliary body Constrictor pupillae in iris at pupillary border Dilator pupillae radially running muscle in iris

Question 27

what is the Pupillary reaction to Increased/decreased illumination?

Answer 27

Increased illumination parasympathetic-both pupils constrict | Decreased illumination sympathetic-pupils dilate

Question 28

what is direct and consensual reflex?

Answer 28

Light shined into eye=direct reflex | The other eye has no light shined at it, but constricts anyway=consensual reflex

Question 29

what is anisocoria?

Answer 29

Pupils of different sizes eg: Horner’s syndrome, can be caused by trauma

Question 30

What are some common causes of absent/abnormal pupillary reflex

Answer 30

Diseases of the retina – detachment/ degenerations or dystrophies Diseases of the optic nerve – such as in optic neuritis (frequently seen in MS) Diseases of the III cranial nerve (efferent limb)

Question 31

what is horner's syndrome?

Answer 31

Anisocoria due to damage to the sympathetic innervation to the pupil.

Question 32

what are symptoms of horner's syndrome?

Answer 32

on affected side: constricted pupil Drooping of the upper eyelid Little or no sweating