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Flashcards in Vision 2 Deck (32):
1

what are the roles of intrinsic muscles?

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

2

what are the roles of extrinsic muscles?

move the eye

3

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

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

4

what are the actions of MR?

Adduction

5

what are the actions of LR?

Abduction

6

what are the actions of SR?

Elevation
Adduction
Intorsion

7

what are the actions of IR?

Depression
Adduction
Extorsion

8

what are the actions of SO?

Intorsion
Depression
Abduction

9

what are the actions of IO?

Extorsion
Elevation
Abduction

10

what do you look for in right third nerve palsy?

Drooping eyelid
Eye can move only laterally (and slightly down)

11

what do you look for in left forth nerve palsy?

Eye moving up when adducted

12

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

Eye being adducted
Eye not able to abduct

13

what is Strabismus?

squint-Misalignment of the eyes

14

what are the 2 different types of squint?

Esotropia (manifest convergent squint)
Exotropia (manifest divergent squint)

15

what is ambylyopia?

(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)

16

what is diplopia?

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

17

what is the definition of the visual field?

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

18

where do the medial nasal fibres cross to opposite side?

optic chiasma

19

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

ALL fibres from the opposite half of the visual field

20

where do the fibres from the optic tract synapse?

LGB of the thalamus

21

where is the primary visual cortex?

occipital lobe

22

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

blindness in one eye

23

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

bitemporal hemianopia- lateral vision of both eyes affected

24

What damage do you expect when optic tract is damaged?

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

25

What damage do you expect when optic radiation is damaged?

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

26

what are the 3 Intrinsic eye muscles?

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

27

what is the Pupillary reaction to Increased/decreased illumination?

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

28

what is direct and consensual reflex?

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

29

what is anisocoria?

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

30

What are some common causes of absent/abnormal pupillary reflex

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)

31

what is horner's syndrome?

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

32

what are symptoms of horner's syndrome?

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