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Opthamology > Visual Loss and Blindness > Flashcards

Visual Loss and Blindness Flashcards

1
Q

name 7 causes of sudden visual loss

A 
vascular
vitreous haemorrhage
retinal detachment
age related macular degeneration (wet type)
closed angle glaucoma
optic neuritis
stroke
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2
Q

what is the main blood supply to the eye?

A

branches of the ophthalmic

  • posterior ciliary arteries (either side of central retinal artery)
  • central retinal artery (in the middle)
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3
Q

occlusion of what can cause sudden visual loss?

A 
retinal circulation (retinal artery/vein)
optic nerve circulation
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4
Q

haemorrhage from where can cause sudden visual loss?

A

abnormal blood vessels

normal blood vessels

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5
Q

what does the central retinal artery supply?

A

2/3rds of retina

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6
Q

symptoms and signs of occlusion of retinal circulation (central retinal artery)

A 
sudden vision loss
painless
RAPD
pale, oedematous retina (as vessels occluded so not red)
thread like retinal vessels
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7
Q

why is the macula normal in central retinal artery occlusion?

A

no ganglion cells in macula

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8
Q

name 2 causes of central retinal artery occlusion (CRAO)?

A

carotid artery disease

emboli from the heart (unusual)

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9
Q

name 2 further variants of CRAO

A

branch retinal artery occlusion (less severe as only a branch, problems in bottom half of vision)
amaurosis fugax

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10
Q

what are the features of amaurosis fugax?

A

transient, painless visual loss
“like a curtain coming down”
lasts 5 mins with full recovery
usually nothing abnormal on examination

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11
Q

management of amaurosis fugax?

A

urgent referral to stroke clinic

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12
Q

virchows triad?

A 
hypercoagulable blood (e.g cancer)
turbulent blood flow (e.g hypertension)
endothelial damage (e.g diabetes)
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13
Q

signs and symptoms of central retinal vein occlusion?

A

sudden visual loss (severity dependent on level of ischaemia)
retinal haemorrhages
dilated, tortuous veins
disc swelling and macular swelling
can have cotton wool spots (markers of ischaemia)
can have fluid build up around macula (oedema)

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14
Q

artery vs vein occlusion (colour)?

A 
artery = pale
vein = dark
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15
Q

what vessels supply the optic nerve?

A

posterior ciliary arteries

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16
Q

what is ischaemic optic neuropathy?

A

occlusion of optic nerve head circulation

posterior ciliary arteries become occluded, resulting in infarction of the optic nerve head

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17
Q

name a cause of ischaemic optic neuropathy and how this occurs?

A

giant cell arteritis
medium to large sized arteries inflamed (via multinucleate giant cells) > lumen of artery becomes occluded (posterior cilliary arteries) due to gross thickening of artery wall > visual loss from ischaemia of optic nerve head

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18
Q

symptoms and signs of ischaemic optic neuropathy?

A

sudden severe visual loss
irreversible blindness
swollen optic nerve

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19
Q

6 symptoms of giant cell arteritis?

A 
headache (usually temporal)
jaw claudication
scalp tenderness
tender/enlarged scalp arteries
amaurosis fugax
malaise
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20
Q

where does haemorrhage often occur into and what is this known as?

A

into vitreous cavity

known as vitreous haemorrhage

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21
Q

how can haemorrhages occur in the eye?

A

bleeding occurs from abnormal vessels (e.g retinal ischaemia in diabetes or retinal vein occlusion causes abnormal, fragile new blood vessels to form
bleeding can occur from normal vessels (e.g vessel bridging a retinal tear)

22
Q

name 5 signs and symptoms of vitreous haemorrhage

A 
loss of vision
floaters
loss of red reflex
may see haemorrhage on fundoscopy
find a cause
23
Q

4 signs and symptoms of retinal detachment?

A

painless loss of vision
sudden onset of flashes/floaters (mechanical separation of sensory retina from retinal pigment epithelium)
may have RAPD
may see tear on ophthalmoscopy

24
Q

what can cause a retinal detachment?

A

tear in retina
vitreous humour can pull on the retina causing a tear
vitreous humor (which is more liquid in older people) can go through the hole and get behind the sensory retina and separate it from the retinal pigment epithalium

25
Q

what is the most common cause of blindness in the west?

A

age related macular degeneration (ARMD)

26
Q

what are the 2 types of ARMD?

A

wet (sudden visual loss)

dry (gradual visual loss)

27
Q

risk factors for ARMD?

A

increasing age
smoking
family history
poor nutrition

28
Q

what happens in wet ARMD?

A

new vessels start to grow from the choroid up into the retina
leakage causes build up of fluid/blood and eventually scarring

29
Q

5 signs and symptoms of wet ARMD?

A

rapid central visual loss
distortion (metamorphosia) = straight lines look wiggly
haemorrhage/exudate
swelling/raised up area on imaging (fluid build up)
pale area on retina (oedema from fluid)

30
Q

what is glaucoma?

A

progressive optic neuropathy

ultimately results in optic nerve damage and therefore visual loss

31
Q

what are the 2 types of glaucoma?

A 
open angle (angle between iris and cornea)
closed angle
32
Q

what happens in closed angle glaucoma?

A

aqueous humour encounters increased resistance through iris/lens channel
increased pressure gradient causes peripheral iris to bow forward, obstructing trabecular meshwork - pressure increases

33
Q

features of closed angle glaucoma?

A 
acute (ophthalmic emergency)
painful, red eye
sudden visual loss
headache
nausea and vomiting
cloudy cornea
dilated pupil
34
Q

immediate management of closed angle glaucoma?

A

need to lower IOP with drops/oral medication to prevent blindness

35
Q

general presentation of gradual visual loss?

A

usually bilateral
often asymmetrical
may present early with reduced VA
may present late with decreased field

36
Q

name 5 causes of gradual visual loss

A 
cataract
age related macular degeneration (dry)
refractive error
glaucoma
diabetic retinopathy
37
Q

what is cataract?

A

cloudiness of the lens
abnormal changes in lens protein (crystallina) result in their chemical and structural alteration, leading to loss of transparency

38
Q

causes of cataract?

A 
age related
congenital (intrauterine infection)
traumatic
metabolic (diabetes - sorbitol accumulation)
drug indiced (steroids)
39
Q

what does a nuclear cataract looks like?

A

when beam of light is shone on cornea, shows as greenish/brown colour on lens

40
Q

what does a posterior subcapsular cataract look like?

A

separate distinct beam of light in lens??

41
Q

Christmas tree cataract?

A

crystals in the lens are visible

look like Christmas tree lights

42
Q

name 2 symptoms of cataracts

A

gradual decline in vision (hazy/blurred) that cannot be corrected by glasses
may get glare

43
Q

management of cataract?

A

surgical removal with intra-ocular lens implant if patient is symptomatic

44
Q

what happens in dry ARMD?

A

accumulation of drusen (metabolic by products of pigment epithelium)
drusen builds up and separates the retina from the vascular supply in the choroid, which can lead to ischaemia etc?

45
Q

4 signs and symptoms of dry ARMD?

A

gradual decline in vision
central vision missing (scotoma)
drusen build up below retinal pigment epithelium
atrophic patches on retina

46
Q

how is dry ARMD managed?

A

no cure

supportive treatment

47
Q

what happens in refractive error?

A

eye cannot clearly focus image

48
Q

name 4 types of refractive error

A

myopia (short sighted)
hypermetropia (long sighted)
astigmatism (usually irregular corneal curvature)
presbyopia (loss of accommodation with ageing)

49
Q

management of refractive error?

A

glasses

50
Q

5 symptoms and signs of open angle glaucoma?

A 
often none
optician may discover it
cupped disc
visual field defect
may/may not have high Intra-ocular pressure

Opthamology (18 decks)

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