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Eye disease Term 2 > Optic nerve anomalies and neuropathies > Flashcards

Optic nerve anomalies and neuropathies Flashcards

1
Q

what is a optic nerve disease defined as

A

a disease which involves damage to the retinal ganglion cell axons

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2
Q

list the 4 symptoms of a optic nerve disease

A

loss of vision - if papillomacula fibres are affected (the axons that originate from the macula)

positive scotoma - constricted loss of visual field

desaturation of colours - particularly red colours and over all colour reduction

decreased brightness perception in affected eye - things appear dimmer (if in one eye then can notice the difference)

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3
Q

what are the 4 clinical signs of optic nerve damage

A

RAPD - impaired/retarded conduction of the ON in diseased eye

Reduced contrast sensitivity

Visual field defects

Colour vision impairment - reg/green and asymmetrical

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4
Q

list the 4 types of visual fields defects that can occur from optic nerve damage

and what does each one depend on

A

central

centrocaecal

arcuate

altitudinal

depends where in the optic pathway that the lesion is

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5
Q

how can you detect a colour vision impairment on a patient who has optic nerve damage

A

by testing colour vision in each eye separately rather than bilaterally

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6
Q

which 4 signs of optic nerve damage can be picked up by careful evaluation of ophthalmoscopy

A

swelling - total or sectoral

diffuse dropout of RNFL

optic atrophy - 1 months after acute injury to the optic nerve

disc drusen - is not a consequence of optic nerve disease, but if you see a swollen optic disc then you need to exclude the possibility that they might have some disc drusen

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7
Q

what are the 2 classifications of optic nerve anomalies

A

congenital

or

acquired

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8
Q

list the 7 types of congenital optic nerve anomalies

A 
hypoplasia 
coloboma
optic disc pit 
tilted disc 
drusen
glial remnants 
myelinated fibres
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9
Q

list the 4 types of acquired optic nerve anomalies

A

papilloedema
optic atrophy
optic neuritis
AION

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10
Q

what is optic nerve hypoplasia

how does it look

what 2 causes may it be associated with

A

the underdevelopment of tissue or organ - subnormal number of axons with normal mesodermal and glial tissue

it is an abnormally small disc and tortuous blood vessels which are not pathological (it is a physiological variant oh hypoplasia)

may be associated with:
parental alcohol
or
parental drug abuse

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11
Q

what type of condition is optic nerve hypoplasia

what symptom is it associated with and under what condition

what other manifestations does it have and name 3 of them

A

non progressive
non inherited

associated with vision loss - only is papillomacula fibres are affected (i.e. if a subnormal amount of macula axons)

it has other systemic manifestations:

  • pituitary and endocrine disorders
  • short stature
  • agenesis of corpus callosum/septum pellucidum (brain/developmental disorders)
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12
Q

what 2 things can you do for management of optic nerve hypoplasia

A

if associated with astigmatism - correct refractive errors to avoid amblyopia

refer px if not already been investigated - because may have systemic associations

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13
Q

what is a optic disc coloboma

how does the disc appear to look

what is the inheritance type

A

incomplete closure of the embryonic fissure - during stages of ocular development

disc is enlarged - with a sharply demarcated white bowl shaped excavation inferiorly
it may extend inferiorly to involve the retina and choroid

sporadic or autosomal dominant inheritance

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14
Q

list the appearance of a optic disc coloboma (4)

A
  • disc is enlarged - with a sharply demarcated white bowl shaped excavation inferiorly where the fissure hasn’t closed
  • it may extend inferiorly to involve the retina and choroid - the retina appears thin and translucent because of the incomplete closure
  • superior disc is fully developed
  • green around the areas of the coloboma = where the incomplete closure is
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15
Q

what is the symptom of a optic disc coloboma

what else may it be associated with

what is the ddx

A

va may be affected depending on the severity

may be associated with neurological defects

ddx = glaucoma

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16
Q

list 3 things that you will do as management of an optic disc coloboma

A

as its a congenital abnormality - monitor the visual field defect which they will already have due to the coloboma

ensure no associated glaucomatous changes - so check IOPs

inform the GP and patient - refer routinely if your diagnosis is uncertain i.e. if you think its glaucoma, write your ddx in your referral if your uncertain

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17
Q

list 3 optic disc coloboma complications and which speed of referral is required for each

A

serous retinal macula detachment - soon referral

progressive visual field loss associated with neural retinal thinning - routine referral to Hes

rhegmatogenous retinal detachment (break in the retina from the coloboma) - urgent referral to Hes

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18
Q

what is a optic disc pit

what appearances can they have

where abouts in the disc is it most commonly found

A

a crater in the optic disc

round/oval
grey white/yellow
= so could be different sizes and different colours

commonly temporal - but could be anywhere

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19
Q

what does a optic disc pit represent

A

the herniation of rudimentary neuroectoderm tissue

20
Q

what are the complications of a optic disc pit

A

variable VF defects - paracentral arcuate connected to the blind spot

depending on amount of papillomacula bundle fibres affected - px may or may not have VA affected

45% of eyes with optic disc pits develop serous retinal detachments

  • fluid from the vitreous cavity OR sub-arachnoid space around the optic nerve
  • macula - affected if pit is temporal and the fluid can make its way to the macula
21
Q

what symptom will occur in a optic disc pit if the fluid from the virtuous cavity or sub-arachnoid space reaches the macula and what should you do if this occurs

A

from a temporal optic disc

metamorphopsia/distortion in their vision

refer the px soon to the hospital

22
Q

what is your management of someone with a optic nerve head pit if:
previously investigated

not previously investigated

when should you refer the patient soon

A

if previously investigated: do not refer - just educate the px on warnings of symptoms of retinal detachment

if not previously investigated: refer routinely - educate the px

refer soon if presenting with recently reduced visual acuity (with and without the metamorphopsia)

23
Q

what is the cause and appearance of congenital tilted disc syndrome

what else is it associated with

A

non hereditary
titles disc occurs because instead of optic disc entering the globe straight on, it enters the eye at an angle instead

bilateral
superotemporal disc elevated and inferonasal disc displaced posteriorly

associated with thinning of the inferior RPE and choroid (peripapillary atrophy) = lost neural tissue and myopic astigmatism

24
Q

what is the complications of titled disc syndrome

A

bitemporal superior quadrantonopia (as nasal fibres damaged)
as both eyes are affected

chiasmal lesions will respect the midline

25
Q

what is optic disc drusen

how does it develop

what is the prevalence

A

hyaline bodies

  • partly calcified
  • maybe has axonal debris

it is present at birth, but starts to manifest in the patient by the time they get to 6 years old at the margins/borders of the optic disc
but it starts off at the deep layers of the retina and then migrates there
as the patient gets older, the drusen gets more calcified

0.3-1.0% of the population
70% bilateral

26
Q

what is the ddx if optic disc drusen

what should you look for to rule this ddx out

what is the management of optic disc drusen

A

papilloedema
- as the disc margins are ill defined

but papilloedema is also associated with cotton wool spots and haemorrhages
look for swelling and elevation of disc margins
- vessel engorgement

refer urgently if diagnosis is uncertain

27
Q

what is a glial remnant of the optic disc

what will it look like and how can it be seen

A

remnant of the hyaloid artery = birdsmeisters papilla

a white sheath will be floating in the vitreous best seen with binocular indirect ophthalmoscopy

28
Q

what are myelinated nerve fibres and how do they form

what do they look like

which types of patients are they more common in

A

asymptomatic
non progressive
myelination of the RGC axons that starts post lamina cribrosa and due to a mis-messaging of oligodendrocytes, this myelination continues into the retina

look like dense white feathers lesion which follows the course of the retinal nerve fibres

maybe more common in down’s syndrome or in patients with neurofibromatosis

29
Q

what are myelinated nerve fibres often mistaken for/ddx

and what differentiates this from its ddx

what is your management

A

mistaken for cotton wool spots

but myelinated fibres are whiter, larger and denser and almost always adjacent to the optic disc

do not refer this patient if there is nothing of concern

30
Q

what is papilloedema

what is it secondary to

A

bilaterally swollen optic discs - due to blockage of retrograde axoplasmic transport

secondary to raised inter cranial pressure

31
Q

list the 6 possible symptoms of papilloedema

A
  • possibly none
  • transient obscuration of vision (TIA) with postural changes - move head to change ICP
  • diplopia - 6th nerve paresis
  • visual acuity only usually affected in terminal stages
  • headaches
  • nausea, vomiting
32
Q

what are the 3 signs of early papilloedema

what are the 4 signs of established papilloedema

what is your management

A

Early
- mild disc swelling and hyperaemia (nasal margins affected first)

  • blurring of disc margins
  • venous engorgement = redness of disc

Established
- disc swelling

  • cotton wool spots
  • retinal folds
  • hard exudates

management = refer this patient immediately to the Hes - to investigate what this papilloedema is secondary to

33
Q

what is optic atrophy and what are the 2 types

A

irreversible degeneration of the optic nerve

primary or secondary

34
Q

what is the primary type of optic atrophy and what is it called

A
  • not associated with another disease
  • hereditary optic atrophy
  • Leber’s hereditary optic atrophy
35
Q

what is the secondary type of optic atrophy and what can be the causes

A
  • associated with another disease
    e. g. px may have had raised ICP and papilloedema, treatment started too late and after it settled down the px will have permanent damage to the optic nerve
  • alcohol/tobacco
  • drug induced
36
Q

what is the sign/appearance of optic atrophy

what are the 4 main symptoms

what is the management

A

pale disc and nrr atrophy as no axons are functioning

symptoms:
- progressive loss of vision
- colour vision
- visual fields
- visual acuity
all affected

management:
if not noted previously, refer to Hes - speed depends on vision and whether its progressive or not

37
Q

what is optic neuritis

what 2 types are there and what are the causes of each type

A

inflammation of the optic nerve
idiopathic - isolated sporadic incidence
demyelination

para-infectious:

  • viral infection
  • immunisation

infectious:

  • cat scratch fever
  • syphilis
  • AIDS
  • herpes zoster
38
Q

what are the 6 signs of demyelinating optic neuritis

A

unilateral visual loss
- v/a 6/18 to 6/60 or even NLP

discomfort on eye movements

dyschromatopsia - R/G colour defects

visual fields defect
- loss in central field due to centrocaecal type vf loss

RAPD
- due to impaired conduction of nerve

normal appearance of optic nerve head because its retrobulbar
- occasionally papilitis

39
Q

what is the prognosis of demyelinating optic neuritis

what is a drawback to the prognosis

what is the purpose of treatment

what is the optometric management

A

recovery

  • begins within 2-3 weekend maximal after 6 months
  • 75% recover visual acuity of 6/9 or better

but disease is characterised by relapses if its secondary to a demyelinating disease e.g. MS

treatment may delay further relapses

refer to casualty unless associated with demyelination - but is they’re established with MS you can just let their physician know

40
Q

what is anterior ischaemic optic neuropathy

what is it caused by

what are the 2 types

what vf defect does it usually have

A

an infarct of the optic nerve head

caused by occlusion of the short posterior ciliary arteries (which supplies the retrobulbar ON with nutrients)

2 types:
non-arteritic
- more common
- not associated with arteritis

arteritic

  • less common
  • associated with arteritis

usually altitudinal hemianopia which respects the horizontal midline

41
Q

which types of patients will suffer from a non-arteritic AION

what symptom will they present with

what will the the appearance of their optic disc

A

males aged 55-70 y/o

presents with sudden painless loss of vision

pale swollen disc with unclear margins
with surrounding disc haemorrhages

(due to the infarct of the short posterior ciliary arteries)

42
Q

what are the 3 risk factors of non-arteritic AION

what is the prognosis

what is your management

A

‘at risk’ disc = all absent cup and disc, so nerves leaving the eye are congested and so can easily get occlusion of the posterior ciliary artery

hypertension

arteriosclerosis

prognosis:
no treatment possible
30% lose vision in other eye within two years (so try to treat systemic disease soon)

refer to casualty - arteritis needs to be excluded (as we can’t be sure if its arteritic or non-arteritic)

43
Q

what is the symptoms of arteritic AION

what may this be preceded by

what age group does this occur in

A

sudden profound unilateral loss of vision

may have episodes of a TIA before the AION

between 60-70 y/o

44
Q

what are the 8 symptoms of temporal arteritis

and what is it caused by

A 
temporal headaches 
neck ache or stiffness 
jaw claudication 
malaise 
weight loss 
morning stiffness 
depression 
tender inflamed ocular arteritis

caused by AION

45
Q

what is the management of temporal arteritis and what is the risk

what 3 things are done in hospital to treat temporal arteritis

what is the prognosis

A

ophthalmic emergency - as theres a risk of visual loss in the other eye and cerebral vascular account (as its inflamed arteries it can be anywhere in the body)

in hospital:

  • temporal artery biopsy
  • erythrocyte sedimentation (ESR)
  • treated with high doses of oral steroids

visual acuity dos not recover

Eye disease Term 2 (23 decks)

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