OPTIC NERVE DISEASES & VISUAL FIELD Dr. Canan Aslı Yıldırım Ophthalmology

Signs of optic nerve dysfunction Reduced visual acuity Diminished light brightness sensitivity Dyschromatopsia Afferent pupillary conduction defect

OPTIC NERVE DISEASES 1. Clinical features 2. Special investigations 5. Leber hereditary optic neuropathy 3. Optic neuritis 4. Anterior ischaemic optic neuropathy Retrobulbar neuritis Papillitis Neuroretinitis

Clinical features Reduced visual acuity Visual field defects Diminished pupillary light reactions Impairment of colour vision Diminished light brightness sensitivity

Uniocular light stimulus evokes bilateral and symmetric pupillary constriction.

Applied anatomy of afferent conduction defect Anatomical pathwaySigns Equal pupil size Light reaction - ipsilateral direct is absent or diminished - consensual is normal Near reflex is normal in both eyes Total defect (no PL) = amaurotic pupil Relative defect = Marcus Gunn pupil 3rd

Optic disc changes Retrobulbar neuritis Early compression Normal Papilloedema Papillitis and neuroretinitis Swelling Optic nerve sheath meningioma Occasionally optic nerve glioma Optico-ciliary shunts Postneuritic Compression Atrophy AION Hereditary optic atrophies Papilledema; increased ICP, hyperemia of the disc, tortuosity of the veins, blurring and elevation of the margin of the disc with hemorrhages (intracranial mass,pseudotumor cerebri,severe acut hipertension)

Classification of optic neuropathies Optic neuritis –Retrobulbar neuritis –Papillitis –Neuroretinitis Ischemic optic neuropathy Hereditary optic neuropathy Toxic optic neuropathy Post-infectious optic neuropathy

Papilledema: bilateral, good central vision Papillitis: inflamatory edema of the disc(anterior optic neuritis):unilateral, decreased VA, impaired color vision, afferent pupillary defect Retrobulbar neuritis: loss of vision, normal- appearing optic nerve and pain on movement of the eye

A. Optic neuritis Retrobulbar neuritis (normal disc) Demyelination-most common Sinus-related (ethmoiditis) Lyme disease Papillitis (hyperaemia and edema) Viral infections and immunization in children (bilateral) Demyelination (uncommon) Syphilis Neuroretinitis (papillitis, macular star) Cat-scratch fever Lyme disease Syphilis

Special investigations Orbital fat-suppression techniques in T1-weighted images Assessment of electrical activity of visual cortex created by retinal stimulation MRI Visually evoked potential

Optic neuritis Women %74, men %34 %70 with multiple sclerosis Uhthoff’s phenomenon + Clinical features; -acute onset of monocular visual loss -periocular discomfort -frontal headache - impairment of colour vision

Multiple sclerosis A common idiopathic demyelination disorder of the CNS characterized by intermittent disturbances of neurological function Clinical features; spinal cord lesions (weakness, stiffness, muscle spasms) brain stem lesions (diplopia, nistagmus, ataxia, dysarthria) hemisphere lesions (depression,dementia,hemianopia,hemiparesis) transient phenomena (epilepsy, uhthoff’s phenomenon)

Uhthoff’s phenomenon Sudden, temporary worsening of visual or other symptoms brought on by physical exercise or increase in body temperature

Diagnosis of Multiple sclerosis Lumbar puncture Evoked potential recordings Magnetic resonance imaging (MRI)

B. Ischemic optic neuropathy 1.Non-arteritic 2.Arteritic

B1.Non-arteritic AION Pale disc with diffuse or sectorial oedema Eventually bilateral in 30% (give aspirin) Age years Altitudinal field defect Presentation Acute signs Few, small splinter-shaped haemorrhages Resolution of oedema and haemorrhages Optic atrophy and variable visual loss Late signs ISCHEMIC OPTIC NEUROPATHY; Non arteritic or arteritic

Non-arteritic AION Monocular sudden, painless visual loss Visual field defect (altitudinal hemianopia, arcuate defects, central scotoma) Colour vision is diminished

FFA in acute non-arteritic ION Generalized hyperfluorescence Increasing localized hyperfluorescence Localized hyperfluorescence

Non-arteritic AION Altitudinal hemianopia Central scotoma Arcuate defect

B2. Arteritic AION Affects about 25% of untreated patients with giant cell arteritis Severe acute visual loss Treatment - steroids to protect fellow eye Bilateral in 65% if untreated Pale disc with diffuse oedema Few, small splinter-shaped haemorrhages Subsequent optic atrophy

Superficial temporal arteritis Headache Age years Scalp tenderness Presentation Superficial temporal arteritis Jaw claudication Polymyalgia rheumatica Temporal artery biopsy ESR - often > 60, but normal in 20% C-reactive protein - always raised Special investigations Acute visual loss

Histology of giant cell arteritis High-magnification shows giant cells Granulomatous cell infiltration Disruption of internal elastic lamina Proliferation of intima Occlusion of lumen

C. Leber hereditary optic neuropathy Maternal mitochondrial DNA mutations Signs Disc hyperaemia and dilated capillaries (telangiectatic microangiopathy) Vascular tortuosity Swelling of peripapillary nerve fibre layer Presents Typically in males - third decade Occasionally in females - any age Initially unilateral visual loss Fellow eye involved within 2 months Bilateral optic atrophy Subsequent bilateral optic atrophy

D. Toxic optic neuropathies Toxic amblyopia -heavy drinkers and pipe smokers -slowly progressive, bilateral,visual impairment -loss of colour vision -centrocaecal scotoma -treatment: 1000 units hydroxycobalamin 10 wks, abstain from drinking-smoking

Toxic optic neuropathies Ethambutol-ınduced optic neuropathy -sudden,dramatic visual loss -impairment colour perception -visual field temporal defect - drug is stopped (recovery time-12 mo)

E. Post-infectious optic neuritis Acute papillitis Measles,mumps,chickenpox,immunization Acute severe visual loss in both eyes Headache, ataxia Treatment; unnecessary (spontaneous recovery) IV steroids for dramatic improvement

VISUAL FIELD

Fovea Horizontal raphe Nasal fibers Arcuate fibers Maculopapillary bundle

Visual Field Defects Scotoma Hemianopia Homonymous hemianopia Bitemporal hemianopia

SCOTOMA: an area of abnormal or absent vision within intact visual field HEMIANOPIA: loss of half the visual field (vertical or horisontal;altitudinal) HOMONYMOUS HEMIANOPIA: loss of either the right or the left half of the visual field in both eyes BITEMPORAL HEMIANOPIA: loss of right half of the visual field in the right eye and loss of the left half of the visual field in the left eye

Scotoma

Visual pathways wih associated field defects 1.Optic nerve Monoocular loss of vision 2.Optic nerve merging Monoocular loss of vision with chiasm associated with contralateral impairment of temporal field 3.Optic chiasm Bitemporal hemianopia 4.Optic tract Totaly homonymous hemianopia 5.Temporal lobe Upper homonymous hemianopia 6.Geniculate body Rare total homonymous hemianopia 7.Parietal lobe Lower homonymous hemianopia 8.Occipital lobe Variety of homonymous hemianopia

Anterior ischemic optic neuropathy (AION)

Altitudinal visual field defect due to central retinal artery inferior branch occlusion Anterior ischemic optic neuropathy

Bilateral optic nerve sheath meningioma

Optic chiasm Craniopharyngioma Hypohysis adenoma Suprasellar meningioma Aneurysms

Craniopharyngioma Endocrinological disorders in children Visual field defects in adults HM CF The posteriorly crossing fibres are most vunerable Craniopharyngioma LE RE

Craniopharyngioma

LE RE Decussating fibres are most vunerable Hypophysis tumour

Hypophysis adenoma

Bitemporal hemianopsia Hypophysis adenoma

Meningioma LE RE Junctional scotoma Tuberculum Sella meningioma Olfactory groove meningioma Sphenoid ridge meningioma

Left homonymous hemianopsia

Right homonymous hemianopsia

Suprasellar aneurysm - optic tractus

Arteriovenous malformation Right homonymous hemianopsia

Posterior fossa tumour

A right sided lesion producing left incongrous inferior quadranopsia

Occipital lobe lesion Left homonymous hemianopsia with macular sparing

Cortical blindness Vascular infarct LR+, retina normal Central vision preserved

Central scotoma : optic nerve lesion Bitemporal field defect : chiasmal disease Homonymous visual field defect : retrochiasmal damage to the optic tracts, radiations, occipital cortex Pituitary adenoma : bitemporal hemianopia Stroke : homonymous hemianopia Summary - Visual Field Defects

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