Approach to Disc Pallor and Automated Fields in Neuro-

ophthalmology

Dr.Shah-Noor Hassan FCPS,FRCS(Glasgow)

Approach to Optic disc pallor

Types of optic atrophy• Primary• Secondary• Consecutive• Temporal pallor• Glaucomatous

Primary optic atrophy

• cause not detected ophthalmoscopically • eg, pituitary tumor, optic nerve tumor, traumatic optic

neuropathy, multiple sclerosis ,toxic/nutritional

• Fundus features of disc Color-chalky white Margins-sharp Demarcated cup Cup may be enlarged normal retinal vessels

Secondary optic atrophy

• eg, papilledema, papillitis • Damage due to swelling of the disc with glial proliferation

• Fundus features of disc

Color-yellow waxy/dirty white Margins-blurred Obliterated cup Perivascular sheathing Retinal vessels attenuated

classification

Pathologic classification • Ascending optic atrophy - follows damage to

RGC/nerve fibre layer

• Descending optic atrophy - retrolaminar optic nerve/chiasma/optic tract

• Trans-synaptic degeneration- seen in patients with occipital damage incurred either in utero or in early infancy.

Unilateral optic atrophy

Ischemic (anterior ischemic optic neuropathy, retinal occlusive disease)

Compressive (orbital, anterior fossa)

Inflammatory (demyelinating, infectious,Autoimmune, sarcoid)

TraumaticInfiltrative

Bilateral optic atrophy

GlaucomaSecondary to retinal degenerationPost-papilledemaCongenital anomalies: hypoplasia, colobomaMethyl alcohol toxicityInherited ON : LHON, Auto dominantNutritional/toxic

Optic Atrophy

• Varies from temporal pallor to chalky white• Due to changes in blood supply, axonal loss,

glial tissue• Also nature and extent of injury/damage

Differentials

• Axial myopia• Optic nerve hypoplasia• Brighter-than-normal luminosity• Optic nerve pit• Myelinated nerve fibers• Scleral crescent• Optic disc drusen• Tilted disc

Myelinated nerve fibers

Optic nerve hypoplasia

Optic atrophy

• Slight, moderate, severe

• Diffuse or sectoral

Optic atrophy

• Color of disc not indicative of atrophy• Often temporal side of disc has less color than

nasal side• O.A diagnosis is based on

-color of disc,changes in vessels,nf layer

- v.a, color vn, VF, pupils,VER

0ptic atrophy

• In AION – Limited to upper and lower quad• Chiasmal lesions – temp and nasal

pallor(bowtie or band atrophy) due to crossing nasal fibres being involved

Also seen in eye contralateral to unilateral optic tract lesion

Causes of primary optic atrophy

IdiopathicDemyelination Post inflammatoryToxic Inflammation of orbit, sinus and meningesCompressive Nutritional Hereditary

Causes of secondary optic atrophy

• Anterior ischaemic optic neuropathy • Papllitis• Papilledema• Metabolic diseases (Diabetes)

Optic disc pallor

Clinical approach

• Demographic profile

–Age

- Gender

- Race• Clinical history

Optic disc pallorDemographic profile

• Age – most important of demographic parameters

• No watertight compartments• Significant overlaps between age groups• Glaucoma can present with pallor at any age

Optic disc pallor

• Gender can guide in favour of a diagnosis but not always

• Male: LHON, Traumatic ON,Tapetoretinal deg,ToxicON,Occupational(heavy metal exposure), lead, arsenic,Nutritional(chronic alcoholism)

• Female: MS, Meningioma, Autoimmune/collagen vasc dis.,Sheehan synd, ecclampsia

Optic disc pallor- Racial differences

• Blacks – lower incidence of Ischaemic ON, better visual fn in IIH

• Caucasians more likely for MS than Hispanics and Asians

• Overall Optic atrophy more in blacks than whites

Optic disc pallor- Clinical history

• Onset –over hrs or days- Optic neuritis, Iscemic ON, Traumatic ON

Subacute- over few days – in demylenating, compressive

• Course- resolved naturally, recurrent episodes- demyelinating

residual poor vn ,progressive,protracted course- other pathologies

Optic disc pallor -History

• Laterality

- Unilateral – Typical ON

NAION

Traumatic ON

Compressive

- Bilateral - Toxic, Nutritional,Hereditary,Arteritic AION, Atypical Optic neuritis

Optic disc pallor - History• Systemic – fever, jaw claudication,

palpitations, dyspnoea, hypertension,diabetes,thyroidTB etc

• Ocular painful eye movements, diplopia, proptosis

• CNS –Headache, vomiting,TIAs, motor deficits, paraesthesias etc.

• Trauma• Family history• Medications- for toxic

Optic disc pallor –Ocular Exam

• V.A.• Visual Fields• Color Vision• Pupils• Fundus – Disc color, cup, margins,

vascularity(Kestebaum count -10 capillaries on disc. In optic atrophy<6)

• RNFL Defects – Red free green filter exam

Optic disc pallor – diagnosis by optic disc appearance

• Ischaemic – pallid edema- arterial

attenuation,sheathing- superior /inferior disc

pallor- Haemorrhages- fellow eye small cup-disc

ratio(disc at risk)

Inferior disc oedemaDilated inferior veins

Disc at risk

Optic disc pallor - Infective

• Macular star• Mild pallor or oedema

Disc pallor- Toxic/nutritional• Temporal disc pallor, bilateral

Disc pallor-LHON/DOA• Temporal, occasionally diffuse

Optic disc pallor- Chiasma/tract lesion

• Bowtie/band atrophy

Glaucomatous

Nonglaucomatous

Optic disc pallor• Compressive neuropathy– unilateral or bil edema– painless progressive

pallor– shunt vessels

Optic disc pallor- papilloedema

• Dirty grey pallor, bilateral, blurred margins, obscured cup and gliosis, attenuation of vessels

Papilloedema -stages

Disc pallor – systemic exam

Look for• Nutritional deficiency• B.P• Anemia• Lymph nodes• CVS /CNS

Optic disc pallor-Ocular investigations

At baseline and followup• V.A• Color Vn• Contrast sensitivity• VF• FFA(if necessary)• OCT• VER/ERG

Optic disc pallor- Investigations

First line

1.Haemogram,peripheral smear,TLC,DLC

2.ESR

3.Mx

4.Chest Xray

5.MRI Head and Orbit with thin cuts and fat suppression

6.VDRL

7. LP(if reqd)

Optic disc pallor- Investigations1.Sarcoidosis-Serum ACE, serum Ca, CT chest

2.Collagen dis- Immunology workup;ANA,RF

3.Nutritional- Serum B12, Folate levels

4.Toxic-heavy metal screening

5.TORCH

6.Hereditary-LHON mutation(full mitochondrial sequencing or common mutations 11778,3460,14484)

7.NMO ab for Devic’s. MRI Spine

8. Thyroid functions- T3,T4 and TSH levels

9.Temporal artery biopsy for AAION

VISUAL FIELD EVALUATION

VF testing strategies

• Confrontation• Goldmann kinetic or static• Humphrey static automated

Confrontation fields

Presentation Outline

1. General aspects of automated perimetry

2. Components and basics of interpreting visual field reports

3. Physiological basis of visual field defects in neurological afflictions

4. Clinical examples discussing the topographic representation of visual fields

5. Visual field alterations in neuro-ophthalmological afflictions

6. Algorithm for field assessment and interpretation

7. Review of various field defects

Why choose automated perimeters: Humphrey perimeter

Advantages of Automated Perimetry •Provides more sensitive and reproducible results •Provides quantitative information•Provides results in a more timely and precise manner •Experienced perimetrist is not required

Advantages of Static Perimetry •Scotomas better defined•Temporal summation of stimulus possible•Less dependence on Perimetrist

Patient Information

• Name• Age• Refractive Error• Visual acuity• Pupil Diameter

• Stimulus/Target• Strategy• Fixation• Gaze monitor

Reliability Indices

• Fixation Losses• False Positive• False Negative

• High fixation losses maybe pseudolosses due to misalignment or true in cases of central vision loss

• High FP rates almost always indicate unreliable test

• High FN rates in abnormal fields are common in perfectly attentive patients

• In normal visual field it shows patient was inattentive

Test Parameter

• Any Patient with visual loss unexplained on Ocular or refractive basis should have a visual field examinatin as the very next test.

Extent of normal visual field

• Nasally 60 degrees• Superiorly 60 degrees• Inferiorly 70 to 75 degrees• Temporally 100 to 110 degrees

Interpretation of Humphrey visual Field

Why is the Grey scale plot suited for field assessment in Neuro-ophthalmology cases

• Optic nerve diseases are more likely to result in absolute field losses

• Absolute field defects are very clearly demarcated on grey scale plots

• These visual fields often respect the vertical meridians and these are well defined on grey scale plots

• Orientation of scotoma with respect to the blind spot is best appreciated on the grey scale plots

Effects of distortion or obscuration

• Of light entering eye

by eyebrows, skin of lid

Lens rim, spectacle power(high plus/minus),incorrect lenses

• By eyelids and media

Pupil size,opacities in media

Basis of visual field defect• Anatomical structure of retinal nerve fibres-

which has 4 groupings which enter Optic disc

a.Inf. Ret n. fibres subserve Sup. visual field

b.Sup. Ret. N. fibres – Inferior visual field

c.Fibres bet macula & optic disc(papillomac bundle)- central Vn

d.Nasal fibres which enter disc in wedge shaped manner

Basis of field defect• Superior and Inferior fibres form arcuate

bundles around papillomacular bundle to enter optic nerve at 12 o’ clock and 6 o’ clock

• Peripherally in retina they join horizontal raphe. Fibres do not cross horizontal raphe.

• Arcuate n.f.bundle –arcuate field defect. Nasal extent is hor. Meridian

• Pap-mac bundle-central or centrocaecal scotoma

• Nasal wedge-temporal defect

Basis of field defects

• Optic disc lesions will produce VF defects identical to those of retina

• Posteriorly fibres rotate 90degrees• Macular fibres occupy central core of Optic

nerve• Hence retrobulbar optic nerve lesions produce

more central scotomas.

Basis of Visual Field Defects in Neuro-Ophthalmology

Arrangement of nerve fibres along the course of visual pathway

Lateral Geniculate BodyUpper retina fibers - medial partLower retina fibers - lateral partMacular fibers -posterior 2/3

Preview of field defects seen in

neuro-ophthalmology

Topographic principle of visual field alterations in ret vasc dis

CRVO (Non-ischemic)

BRVO

BRAO

PRP done for Diabetic Retinopathy

Visual Field alterations in nerve fibre layer affliction

Visual field changes in neuro-ophthalmology1. Optic disc pit

2. Tilted optic disc

3. Optic disc drusen

4. Anterior ischemic optic neuropathy

5. Papilledema

6. Hereditary optic atrophy

7. Toxic optic neuropathy

8. Optic neuritis

9. Optic nerve meningioma

10. Pituitary adenoma

11. Craniopharyngioma

12. Optic tract and LGB lesions

13. Optic radiation afflictions

14. Visual cortex lesions

15. Miscellaneous field alterations

Optic disc pit

Tilted optic disc

Crater like optic disc pit

Optic Disc Drusen 60° field

Optic Disc Drusen

Optic Disc Drusen 30° field

AION with cecocentral sparing

Typical AION

Maculopapular ischemia

Papilledema (IIH)

Hemorrhagic Papilledema

Papilledema secondary to astrocytoma

Principle behind cecocentral scotoma

Hereditary optic nerve atrophy

Toxic optic neuropathy

Visual Field defects in optic neuritis

CentralDiffuse depressionAltitudnalNasal hemianopiaNerve fibre bundle defectsCombined defects

Orbital apex meningioma –alt defect

Optic nerve sheath meningioma

Sphenoid ridge meningioma with left orbital apex involvement

Field alterations in chaismal and

perichiasmal lesions

Junctional scotoma in a case of sphenoid meningioma

Pituitary Adenoma

Early stage of pituitary adenoma

Late stage pituitary adenoma- Hemianopia and subtotal defects

Craniopharyngioma Chiasmal meningioma

Field alterations in optic tract and lateral geniculate body lesions

Basal Ganglia neoplasm: Incongruent Hemianopia

Field alterations in lesions involving optic radiations

Astrocytoma of left temporal lobe

Substance defects in left brain

Infarct of left occipital and parietal lobe

Complete hemianopia in total involvement of all optic radiations

Hemianopia with sparing of fixation in subtotal in involvement of all optic radiations

Involvement of all optic radiations after left cystic tissue defect following neurosurgery

Incongruent field losses in occipital lobe infarct affecting the optic radiations asymmetrically

Incongruent field losses in multiple sclerosis seen in a 30-2 field

Incongruent field losses in multiple sclerosis are better demarcated in this 10-2 field

Field alterations in afflictions of the visual cortex

Congruent homonymous hemianopia with macular sparing

Occipital lobe infarct with complete homonymous defects

Occipital lobe infarct with incomplete homonymous defects

Miscellaneous Field Defects

Peripheral field defects

• May be out of field for 30-2• A fast 60-2 protocol used

Bilateral homonynous hemianopia• Seen in vascular lesions• May have both congruent

and incongruent areas

Miscellaneous Field Defects

Central homonymous hemianopia

• Seen in occipital lobe abscess

• Also called reading scotoma

Functional visual field loss

• No organic lesion

Localisation of homonymous hemianopia

• Macular sparing• Congruity• Pupillary response – normal in Op Radiation• Asymmetric OKN -Parietal• Saccadic pursuit to side of lesion-parietal

Algorithm for Field Assessment and Interpretation

• References 1. Field charts referenced from Atlas of Computerized

Perimetry by Weber and Caprioli, Published by W.B. Saunders Co.Philadelphia,2000

2.Clinical Neuro-Ophthalmology by Ulrich Scheifer et al,Publishers,Springer

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