Optic pathway problems Flashcards
What do optic nerve defects affect?
one whole eye OR
horizontal - damage to nerve as it comes into the back of the eye
Name some optic nerve problems?
ischeamic optic neuropathy
optic neuritis
tumours - meningioma, glioma, haemangioma
What is optic neuritis?
progressive visual loss, over 2 weeks, due to the loss of myelin sheath
How long does it take optic neuritis to recover?
weeks to months
What is the presentation of optic neuritis?
pain behind the eye, especially on movement
colour desaturation
central scotoma - blind spot
What can optic neuritis lead to?
death of the optic nerve
What can cause an optic chiasm defect?
pituitary tumour
craniopharyngioma
meningioma - normally around the sphenoid, slow growing, indolent tumour
How do optic chiasm defects present?
bi temporal field defect
What can cause an optic tract defect?
tumours
demyelination
vascular abnormalities
What is the presentation of an optic tract defect?
same side of both eyes affected
macula is NOT spared
defects dont need to be symmetrical in both eyes
What can cause an optic cortex defect?
stroke
demyelination
How do optic cortex defects present?
homonomous defect
macula is spared (because the cortex controls the macula)
symmetry between the defects
