Optic Disc Assessment and Visual Fields Flashcards
where does the optic nerve enter the eye?
the optic disc
what are the three C’s used to describe the optic disc?
contour
colour
cup
what should the contour of the optic disc look like?
clear, well defined border
should be circular
what colour should the optic disc be?
orange-pink on the outside
paler centre
what is the cup of the optic disc?
the pale centre that is devoid of neuro retinal tissue
what is a normal size for the cup of the optic disc?
cup to disc ratio of about 0.3
what are disc drusen?
small collections of material within the optic nerve
what does homonymous mean?
the same part of the field in each eye
what does incongruous mean?
different parts of the field in each eye
what does hemianopic mean?
half of the field is affected
what does quadrantanopic mean?
a quarter of the field is affected
what type of visual loss is caused by optic nerve damage?
complete loss in one eye
aka monocular vision loss
what type of visual loss is caused by a lesion in the optic chiasm?
bitemporal hemianopia
what type of visual loss is caused by a lesion in the occipital cortex?
homonymous hemianopia with macular sparing
what type of visual loss is caused by a lesion in the right optic tract?
homonymous hemianopia
