Vision 2 Flashcards
What is your visual field?
Everything you see with one eye including the periphery
How is visual field assessed?
By confrontation test or automated perimetry
At the optic chiasma, which type of fibres cross to the opposite side?
Nasal fibres
What kind of fibres does the optic tract contain?

Contains fibres from the (lateral) temporal half of the ipsilateral eye and the crossed-over nasal fibres from the contralateral eye.
In terms of visual field, the optic tract contains all the fibres from the opposite half of the visual field
Where do the fibres from the optic tract synapse?
At the LGB of the thalamus
(Lateral geniculate body)
Where do the fibres travel after reaching the LGB?

Optic radiation travels to reach the primary vidual cortex in the occipital lobe
Thus the Right visual cortex sees the left half of the visual field and vice versa.
What damage do you expect when the right optic nerve is damaged?
Blindness in one eye
What damage do you expect when the optic chiasma is damaged in the middle?
Bilateral hemianopia

What damage would you expect with a right optic tract/right optic radiation that is damaged?
Contralateral homonymous hemianopia

What sits below the optic chiasm?
Pituitary gland
Look

What are intrinsic muscles responsible for?
Control pupil diameter & helps alter lens curvature to enable us to see near objects
What are extrinsic muscles responsible for?
They move the eye
What is the origin and insertion of the eye muscles?

What supplies the superior oblique muscle?
The trochlear nerve (CN 4)
What supplies the lateral rectus?
The abducens nerve (CN6)
Apart from the superior rectus and the lateral rectus, what are the other extrinsic muscles supplied by?
Occulomotor nerve (CN3)
What are the following terms for binocular eye movement?
Dextroelevation, elevation, levoelevation
dextroversion, …………..levoversion
Dextrodepression, depression , levodepression
When the lateral rectus is abducting the eye, what is the action of the superior rectus and the inferior rectus?
SR - Causes elevation
IR - causes depression
When the medial rectus has the eye adducted what is the action of the superior rectus and the inferior rectus?
SR causes intorsion
IR causes extorsion
What is the action of the superior oblique and the inferior oblique when the eyeball is abducted?
Superior oblique - intorsion
Inferior oblique - extorsion

What are the actions of the msucles of the eye?
MR
LR
SR
IR
SO
IO

Define strabisumus
Squint
What are the names given to the two types of squint?
Esotropia - manifest convergent squint
Exotropia - divergeant squint

