Ophthalmology Flashcards
(25 cards)
Lesion anterior to optic chiasm
unilateral field defect
Lesion posterior to optic chiasm
Contralateral homonymous defect
Defect at optic chiasm
Bitemporal defect
More congrouous and symetrical defect
Closer to primary visual cortex in occipital lobe
Homonymous hemianopia
Contralateral optic tract affected
Commonly caused by stroke/tumour
Quadrantopia
Bilateral lesion, thus post chiasmal
Bitemporal hemianopia
Lesion at optic chiasm
Usually neoplasia
Pituitary tumour
Bitemporal superior quadrantanopia
Respects vertical but not horizontal midline
Can result in optic neuropathy
Central field defect
Secondary to age-related macular degeneration/optic nerve disease
Symmetrical, subacute, progressive
Reduced colour vision and acuity
Causes of diplopia
Displacement of globe in orbit (trauma, tumour, infection) CN Palsy Decompensated latent squint Extraoccular muscle disease (MG) Thyroid eye disease
Amblyopia
Lazy eye
Acuity
Causes of monocular diplopia
Corneal abnormality (scar)
Uncorrected refractive error
Cataract
Causes of binocular diplopia
Motor nerves
Extraocular muscles
Sign of CN III Palsy
Down and out gaze
Pupillary dilation
Muscles innervated by CN III
Inferior oblique
Medial rectus
Superior rectus
Inferior rectus
Muscles and action innervated by CN IV
Superior oblique
Causes internal rotation of eye mainly
Muscles and action innervated by CN VI
Lateral rectus
Abduction of eye
Causes of CN VI Palsy
Transient and benign in children
Adults: HT, DM, MS, malignancy, trauma, infection, raised ICP
Causes of unilateral optic nerve swelling
Central retinal vein occlusion Non arteritic anterior ischaemic neuropathy Arteritic anterior ischaemic neuropathy Papillitis Neuroretinitis
Central retinal vein occlusion
Common, unilateral severe visual impairment
Retinal haemorrhage
Hyperaemic swollen disc
Large retinal veins
Non arteritic anterior ischaemic neuropathy
Occlusion of short posterior ciliary arteries Infarction of head of optic nerve Painful, monocular sudden loss of vision Reduced acuity Haemorrhages (splinter and flame)
Arteritic anterior ischaemic neuropathy
Sudden, painful monocular loss of vision (Emergency)
Usually >50 YO
Linked to giant cell arteritis (jaw claudication, reduced acuity, non pulsatile tender temporal artery)
Swollen optic disc
RAPD
Flame haemorrhages and cotton wool spots
Papillitis
Inflammation of optic nerve head
Neuroretinitis
inflammation of optic nerve and papillary retina