1
Q
Causes of a Raised Optic Disc
A
- Not swollen but very similar appearance
- Compression
- Infiltration
- Congenital optic neuropathies (Leber’s optic neuropathy)
- Toxic optic neuropathies (methanol poisoning)
- Traumatic optic neuropathy
2
Q
Compression
A
- Orbital masses may compress optic nerve and venous drainage
3
Q
Compression - Symptoms
A
- Monocular
- Slow, compressive visual loss
- VF loss - may be central or diffuse
4
Q
Compression - Signs
A
- Eyelid oedema
- Proptosis
- EOM involvement
- Pupils - RAPD
5
Q
Compression - Disc Appearance
A
- If anterior lesion, get disc oedema (will appear oedematous but will be raised)
- If intraorbital/intracanalicular (further back from ONH), get disc pallor
- If vasculature not compromised, get ON dysfunction and atrophy despite no preceding disc oedema
- If BV’s normal, may get dysfunction without raised appearance
- If swollen or raised, may have simple oedema or visible signs of infiltration
- Optociliary shunt vessels - smaller vessels that dilate up to try and provide blood supply to affected area
6
Q
Compression - Management
A
- Referral for hospital investigations
- MRI and CT scans conducted if lesion suspected
7
Q
Compressive Lesion Types
A
- Optic nerve sheath meningioma
- Optic nerve glioma
- Melanocytoma
8
Q
Optic Nerve Sheath Meningioma
A
- ON sheath surrounds ON providing it with protection
- ON sheath meningioma - Benign tumour
- Proliferation of meningoepithelial cells lining the sheath of the ON
- One third of ON tumours
- Mean age - 40-50 yrs
- More common in females (as are meningiomas elsewhere)
9
Q
Optic Nerve Sheath Meningioma - Signs and Symptoms
A
- Painless, slowly progressive monocular visual loss (95% of cases)
- Proptosis (60-90% of cases)
10
Q
Optic Nerve Sheath Meningioma - Disc Appearance
A
- Optic oedema then atrophy (again after 4-6 weeks)
- Optociliary shunt vessels
11
Q
Optic Nerve Sheath Meningioma - Management
A
- Observe if stable and no visual loss
- Radiotherapy:
- Stability or improvement in up to 94%
- Complications:
- Radiation retinopathy
- Pituitary dysfunction
- Surgery:
- Biopsy or excision
- Risk of ON trauma and visual loss
- Considered if intracranial extension
12
Q
Optic Nerve Glioma
A
- Optic glioma are usually pilocyctic tumours
- Most common primary tumour of ON
- Most are slow growing and benign
- Some are malignant and more rapidly progressing, causing blindness and death
- 70% detected during first decade of life, 90% by second
- Hence less likely if px over 20
- Association with Neurofibromatosis 1 (NF1):
- 10-30% of NF1 have optic gliomas
- 10-70% with optic glioma have NF1
13
Q
Optic Nerve Glioma - Symptoms
A
- Proptosis - 94% (main presenting symptom)
- Visual loss - 87%
- OD pallor - 59%
- OD oedema - 35%
- Strabismus - 27%
14
Q
Optic Nerve Glioma - Signs
A
- RAPD
- VF defect
- Optociliary shunt vessels
15
Q
Optic Nerve Glioma - Management
A
- Observation if good vision and stable imaging appearance
- Chemotherapy if severe visual loss
- Radiotherapy has a risk of complications including pituitary dysfunction
16
Q
Optic Nerve Melanocytoma
A
- Typically a benign pigmented tumour of uveal tract
- Composed of melanocytes and melanin, and don’t grow
- Likes the lamina cribrosa of ONH
- Rarely become malignant
17
Q
Optic Nerve Melanocytoma - Presentation
A
- Can get ON dysfunction if large but usually a coincidental finding
- Black lesion with feathery edges
- Typically small and don’t grow
- Good to monitor with photographs to check if growing
- Growth (if present) will be very slow
- Would take pics every 6/12, not every week
18
Q
Optic Nerve Melanocytoma - Complications
A
- CRVO
- Malignant transformation
19
Q
Optic Nerve Melanocytoma - Management
A
- Observation every 6-12 months
20
Q
Infiltration
A
- Infiltration/invasion of ON by NEOPLASTIC (abnormal growth of cells which replicate - can be benign or malignant replication) or inflammatory cells
- Ocular involvement may be presenting feature of systemic disease
21
Q
Infiltration - Symptoms
A
- Progressive, severe visual loss over days to weeks
- Associated with headache
22
Q
Infiltration - Signs
A
- Retrobulbar infiltration (infiltration behind ONH) - disc appears normal
- Disc involvement - swollen appearance
23
Q
Infiltrative Lesions
A
- Leukaemia
- Lymphoma
- Granulomatous infiltration
- Sarcoidosis, TB, syphilis
- Metastases
- Rare but most commonly from breast or lung cancer (can manifest in the eye)
24
Q
Infiltration - Management
A
- Urgent referral to ophth
Hospital Investigations:
- MRI of brain and orbits
- CSF analysis
- Screening tests for inflammatory/infective/neoplastic disorders
- Early identification allows life-saving treatment
- Palliative care may improve vision if poor prognosis
25
Inherited Optic Neuropathies - Leber's Hereditary Optic Neuropathy
- Hereditary condition characterised by bilateral optic atrophy
- Affects maternal mitochondrial DNA
- More common in males aged 10-30
26
Leber's Hereditary Optic Neuropathy - Signs and Symptoms
- Ask about FH
- Acute, severe, painless visual loss (<6/60)
- Initially monocular but both involved quickly
- Central visual loss
- RAPD when monocular involvement but NOT when BE affected
27
Leber's Hereditary Optic Neuropathy - Disc Appearance
- Normal in up to 40%
- Hyperaemia and elevation of disc
- Thickening of peripapillary retina
- Peripapillary telangiectasia
- Tortuosity of medium sized retinal vessels
- Eventual optic atrophy
28
Leber's Hereditary Optic Neuropathy - Management
- MRI scan to exclude a treatable cause
- Once diagnosed, there is no treatment and visual loss usually permanent
29
Toxic Optic Neuropathies
- Typical history - alcohol/tobacco excess with neglect of diet (B vitamins & thiamine)
- Can get neuropathy in well-nourished individuals with pernicious anaemia (can't metabolise ion properly) or vitamin B12 deficiency
Other causes:
- Methanol intoxication (component of industrial solvents, antifreeze, fuel)
- Amiodarone (treatment of cardiac arrhythmias)
- Tamoxifen (prevention and treatment of breast cancer)
- Ethalbutamol treatment for TB)
- Isoniazid (treatment for TB)
- Isotretinoin (treatment for acne)
30
Toxic Optic Neuropathies - Symptoms
- Chronic (gradual & progressive) or acute, depending on the cause
- Bilateral and symmetrical
- Painless loss of vision
- Dimness of vision (like walking into a cloud)
31
Toxic Optic Neuropathy - Signs
- Affects central vision with central scotoma
- Minimal findings on initial presentation:
- OD can be normal/mild pallor/hyperaemia
- In a small group of px's with hyperaemic discs, could get small splinter haemorrhages on disc edge
- Mild depression on Amsler fixation target (general dimming)
- Reduced CV
- Months-years after presentation:
- Papillomacular bundle dropout
- Temporal disc pallor followed by optic atrophy
32
Toxic Optic Neuropathy - Management
- Investigations of exclusion:
- Fluorescein angiography
- Blood testing
- Electrophysiology
- MRI imaging
- Reversal of inciting cause (can be difficult - alcohol/tobacco abuse, med subs)
- Can get reversal of ocular signs if optic atrophy has not happened
- Optic atrophy is a sign of permanent damage, the nerves are damaged and the disc has gone pale, if that hasn’t happened there is potential to reverse the problem
33
Traumatic Optic Neuropathy
- ON damage from trauma to head/orbit/globe
- Direct traumatic optic neuropathy
- Avulsion of nerve (nerve has dislocated and gone out of its position) from laceration by bone fragments/FB's
- Direct compression from haemorrhage (blood from trauma can directly affect ONH)
- Indirect traumatic optic neuropathy - something hasn’t physically happened to the nerve/gone into the nerve
- Shear forces on nerve (shear force - 2 forces pulling in opposite direction)
- Shear forces on vascular supply
34
Traumatic Optic Neuropathy - Examination
- Visual loss
- Immediate loss
- Severe - no perception of light
- RAPD
- Optic disc
- If pathology is posterior, OD may appear normal
- Eventual atrophy
- Neuroimaging
- Assesses extent of injury and co-morbidity
35
Traumatic Optic Neuropathy - Management
- Neuroimaging to assesses extent of injury and co-morbidity
- Prognosis poor
- Intravenous steroids
- Anti-inflammatory and neuroprotective
- Increased risk of mortality when combined with other head injuries
- Consider when isolated injury with no other evidence of head injury
36
Causes of APPEARANCE of a Raised Optic Disc
- Optic disc drusen
- Tilted optic disc
- Myelinated nerve fibres
- Hypermetropic crowded disc
- Intraocular disease
- Central retinal vein occlusion
- Posterior uveitis
- Posterior scleritis
- Hypotony
37
Optic Disc Drusen
- Calcified nodules within ONH
- 0.34% - 2% of population
- Bilateral in 75%
- Unclear pathophysiology - impaired ganglion cell axonal transport (debris from axonal flow deposited in ONH)
- Buried in childhood, more prominent with age
- Most px's asymptomatic
38
Optic Disc Drusen - Examination
- Possible RAPD if monocular/asymmetric
- Visual fields
- VF loss in 75-87%
- Enlarged blind spot/arcuate defect
- Fibres branch from OD to retina, if those fibres were to die, would cause a VF defect along pathway of that fibre (will follow horizontal midline)
- Remains stable or very slowly progresses
39
Drusen - Optic Disc
- Appears small in diameter (if drusen pushing things inwards)
- Anomalous branching vascular patterns
- Round, whitish, yellow refractile bodies - describe in terms of size (in disc diameters, how many) and location (clock like, or nasal/temporal etc)
- Disc may be pale/atrophy/RNFL loss
40
Buried Drusen vs Swollen Disc
- Both may elevate the OD and blur its margins
- OD drusen does not have:
- Lack of hyperaemia
- Lack of microvascular changes (telangiectasia etc)
- Normal/atrophic nerve fibre layer
- Anomalous retinal vascular patterns
41
Tilted Optic Disc
- 1-2% of the population
- 80% bilateral
- Congenital or associated with myopia (as eye grows in myopia, OD can change and its orientation can tilt)
- Oblique insertion of ON
- Often the area the disc is tilted away from there is atrophy
- Normal vision
42
Tilted Optic Disc - Examination
- Visual field - Bitemporal loss (can be associated with area of atrophy), superior arcuate scotoma
43
Myelinated Nerve FIbres
- 1% of population
- Unilateral in 80%
- Myelin covers the nerves after they have left the ONH - function of myelin is to speed up the transmission of nerves
- During development sometimes the myelin doesn’t stop just behind the ONH and can protrude within the ONH
44
Myelinated Nerve Fibres - Signs and Symptoms
- Usually asymptomatic
- Fundus examination
- Visible yellow patch of myelin around ONH
- Visual fields
- Enlarged blind spot corresponding to the area of myelin (covering photoreceptors so light can't get to that area)
45
Hypermetropic Crowded Disc
- Hypermetropic eyes are smaller and have smaller discs
- Small discs can make BV's look crowded/dilated and can be misdiagnosed for a swollen or unusual looking disc
- BV's just look thicker in comparison to the disc, in reality it is normal
46
Intraocular Disease
- CRVO
- Posterior uveitis
- Posterior Scleritis
- Hypotony
47
Other Optic Neuropathies - Excavated OD anomalies
- OD pit
- Coloboma
- ON hypoplasia
- Morning glory disc syndrome
48
Optic Disc Pit
- Congenital
- Depression of disc surface
- Associated with VF defect
- Serous macular detachment (fluid seeping through hole)
- Communication between optic pit and macula - that area of the disc normally contains the fibres which travel to the macula then you can get some fluid in a tunnel where the fibres should have been
- Can be liquified vitreous or subarachnoid fluid
- That detached area of the retina would have a greyish appearance, normally temporal/inferior to the disc
- Associated central vision loss when situated on maculopapular bundle (bit of fibres that takes information back from the macula to the brain)
49
Optic Disc Pit - Management
- Difficult (higher risk as affects macula)
- Observe (25% spontaneously resolve, some develop macular involvement)
- Argon laser along temporal aspect of disc
- Pars plana vitrectomy (take out vitreous if it is the vitreous that is leaking into the pit)
50
Coloboma
- A focal glistening white, bowl-shaped excavation, decentred inferiorly
- Congenital defect from incomplete closure of the embryonic fissure (gap left at bottom)
- Unilateral or bilateral
- Usually occur inferiorly
51
Coloboma - Examination
- Visual acuity
- Reduced
- Visual Fields
- Superior field defect (as is an inferior disc problem)
- Can mimic glaucomatous loss (as affecting ONH)
- Fundus
- Larger than normal OD
- Can involve uvea and retina if large
52
Colobomas - Associations
- Microphthalmos (small eye)
- Colobomas of iris, choroid and retina
53
Optic Nerve Hypoplasia
- Reduced number of nerve fibres
- In isolation (by chance), part of bigger problem with development or associated with:
- Midline structures of the brain
- Endocrine abnormalities – growth hormone and other pituitary hormones (eye won't grow during development and causes reduced number of nerve fibres and other pituitary hormones)
- Suprasellar tumours
54
Optic Nerve Hypoplasia - Predisposing Factors
- Maternal diabetes
- Agents ingested by mother during pregnancy including alcohol, LSD, quinine, steroids, diuretics, anticonvulsants, cold remedies etc
- Spectrum of severity from asymptomatic to no perception of light depending on how many nerve fibres haven't developed
- Unilateral or bilateral
55
Optic Nerve Hypoplasia - Bilateral Cases
- Roving eye movements (not enough nerve fibres - macula not developed properly - poor vision - can't fixate on something - eye will rove side to side looking for clear vision)
- Sluggish pupil responses - not many fibres working there and taking info about how much light there is
- Less severe bilateral cases:
- Squint in one eye
- Minor VF defects
56
Optic Nerve Hypoplasia - Unilateral Cases
- Squint in affected eye
- RAPD
- Unsteady fixation in affected eye
57
Optic Nerve Hypoplasia - Examination
- Visual Fields
- Peripheral and arcuate defects (as affects ONH)
- Disc appearance
- Small diameter of disc (comparison of 2 eyes useful if unilateral)
- Grey disc colour and surrounding hypopigmentation
- Relatively large retinal BV diameter
- Double ring sing is characteristic - white ring of visible sclera
*If ratio of, disc diameter: disc-fovea distance > 3:1, likely they have this*
58
Optic Nerve Hypoplasia - Management
- Referral for endocrine opinion
- MRI in all cases
59
Morning Glory Disc Anomaly
- Rare congenital malformation, embryonic origin unclear
- Funnel-shaped staphylomatous excavation of the ON
- Usually unilateral
- More common in females
60
Morning Glory Disc Anomaly - Examination
- Visual acuity <6/60
- RAPD
- Visual field loss
- Fundus
- Enlarged disc
- Disc pink or orange colour
- Chorioretinal pigmentation around excavation (blue/grey pigment coming from the choroid)
- White glial tissue on central disc surface
- Retinal vessels appear at periphery of disc
- Serous retinal detachment
Clinical Ophthalmology
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