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新世紀眼科
陳筱諺醫師
Visual Pathway
1. Retina (photoreceptor cells)
⇒ 2. Optic nerve
1
2
⇒ 3. Chiasm
⇒ 4. Optic tract
3
4
⇒ 5. Lateral geniculate body
5
⇒ 6. Optic radiation
6
⇒ 7. Occipital cortex
7
Optic nerve dysfunction
„ VA
„ Pupillary reaction
(afferent pupillary defect)
„ Color vision
„ VF defect
central scotoma)
cecocentral,
altitudinal
Ophthalmoscopic findings
„ Normal
„ Disc edema
„ Opticociliary shunt
„ Disc atrophy
Investigation
„ Automated perimetry
„ MRI
„ VEP
„ FAG
Optic neuritis
„ Retrobulbar neuritis (associated MS)
„ Papillitis (children, bilateral, after viral infection,
headache, seizure)
„ Neuroretinitis (neurosyphilis, cat-scratch fever, lyme
disease)
Optic neuritis associated multiple
sclerosis???
Papilledema
„ Swelling of optic disc head secondary to IICP
Papilledema
„ Increased intracranial pressure (IICP)
„
Headache
„
Vomiting
„
Papilledema
„ CT, CSF
Brain tumor
„ Early papilledema
(NÆSÆIÆT,
loss of venous pulsation,
disc hyperemia,
VA may be normal or
transient blurring)
„ Established papilledema
(disc hyperemia, elevation
disc margin blurred,
venous engorgement,
peripapillary hemorrhage,
cotton wool spot,
VA may be normal or
impaired)
„ Chronic papilledema
( no hemorrhage or cotton wool spot,
prominent elevation of disc
Opticociliary shunt)
„ Atrophic papilledema
(pale and chalky white disc, VA impaired,
after trauma, tumor, brain surgery)
AION (anterior ischemic optic neuropathy)
„ Non-arteritic: NAION
„ Arteritic: AAION
„ Different treatment modality and prognosis
NAION
„ Monocular, sudden, painless visual loss (1/3 mild)
„ Altitudinal VF defect
„ Color vision
„ Pale disc with sectoral or diffuse edema (fellow eye
crowded disc)
„ Old age, HTN, smoking.
„ Fellow eye involved (1/3) Æ pseudo-Foster Kenedy
syndrome
„ No definited treatment
AAION
„ Associated with giant cell arteritis (scalp tenderness,
headache, jaw claudication)
„ ESR, CRP, temporal artery biopsy
„ VA severely impaired
„ Treatment to prevent blindness of fellow eye
(pulse steroid Tx Æ80mg/day Æ60mg/day
Æ…..10mg)
Toxic optic neuropathy (drug induced)
„ Ethambutol, isoniazid, streptomycin, vigabatrin,
chlorpromazine
„ 6%, dose dependant (>2 months)
„ Red-green color perception
„ VF: central or cecocentral scotoma
„ Recovery is good if recognized early
Glaucoma
Visual Pathway
1. Retina (photoreceptor cells)
⇒ 2. Optic nerve
1
2
⇒ 3. Chiasm
⇒ 4. Optic tract
3
4
⇒ 5. Lateral geniculate body
5
⇒ 6. Optic radiation
6
⇒ 7. Occipital cortex
7
Anatomy
„ Retina v.s. visual field --
inverted & reversed
„ Nerve fibers of nasal retina
(53%) decussate across
the chiasm
Optic Nerve
„ Optic nerve gliomas: children (first decade), NF-1, proptosis/
visual loss, fusiform enlargement of optic nerve
„ Optic nerve meningiomas:
middle-aged female
(40-50 y/o), painless progressive
visual loss, optic atrophy
tubular enlargement of ON.
Optic Chiasm
Bitemporal hemianopsias
„ VA sparing
„
Pituitary adenoma
craniopharyngioma
Optic Tract
„ Optic tract syndrome
incongruous homonymous
hemianopsia
Eg. astrocytoma
Band atrophy
Optic Radiations
„ Anterior parietal radiations
„ Pie on the floor
„ Ex: stroke
„ Temporal radiations
„
Pie in the sky
R
L
Occipital Lobe
„ Extremely congruous
homonymous hemianopsia
„ Middle cerebral artery &
posterior cerebral artery
Occipital hematoma
Stroke in the Primary visual cortex
„ Anterior visual cortex: Macula sparing homonymous
hemianopsia--(key hole sparing)
„ Occipital tip: homonymous congruous central scotoma
(middle cerebral artery)
Goldman Perimetry Shows bilateral Concentric Reduction of the Visual Fields,
Leaving an Area of Preserved Vision Around Fixation (Keyhole Vision)
Cortical blindness
„ Normal pupillary response/ optic nerve appearance
„ Bilateral occipital lobe destruction
„ Anton syndrome
denial of blindness
classically associated with cortical blindness
(lesion at any level of visual pathway severe enough to cause blindness)
Pupillary disorder
Pupil
„ Parasympathetic pathway
„ Sympathetic pathway
Parasympathetic pathway
1. Retina
⇒ 2. Optic nerve
⇒ 3. Chiasm
⇒ 4. Optic tract
⇒ 5. Superior colliculus
⇒ 6. Edinger-Westphal nucleus
⇒ 7. Oculomotor nerve
⇒ 8. Ciliary ganglion
⇒ 9. Ciliary nerve
⇒ 10. Iris sphincter
Ocular reflexes
„ ２進３出 (light reflex)
„
„
２進：vision
３出：pupil constriction (parasym)
„ ５進７出 (blinking reflex)
„
„
５進：corneal sensation
７出：orbicularis m blinking (motor)
lacrimal tearing (parasym)
Sympathetic pathway
1. Posterior hypothalamus
⇒ 2. C8-T2
⇒ 3. Superior cervical ganglion
⇒ 4. Cavernous sinus
⇒ 5. Optic canal
⇒ 6. Ciliary ganglion (no synapse)
⇒ 7. Ciliary nerve
⇒ 8. Iris dilator
„ Horner syndrome
„ Miosis, esp. in dim illumination
„ Mild ptosis (Müller’s muscle)
„ Anhydrosis of the affected side of face
Horner’s
LIGHT-NEAR DISSOCIATION
diminished or absent response to light but intact near
response (convergence, accomodation, pupil constriction)
Damage to the pretectal nucleus cause LND
While neurosyphilisis the most common cause of LND ( The
Argyll Robertson pupil) , other causes exist:
„ 1. Advanced diabetes mellitus
„ 2. Tumours of the pituitary gland
„ 3. Mid-brain lesions
„ 4. Aberrant regeneration of cranial nerve III
„ (pseudo - Argyll Robertson pupil)
Eye movement disorder
Oculomotar nerve palsy
„ the eye is turned down and out, severe ptosis
„ Superior/ medial/ inferior rectus muscles, levator muscle,inf
oblique
„ Complete vs incomplete (pupil sparing)
„ Causes :
1. ischemic event from diabetes or hypertension, 25%
idiopathic .
2. aneurysm pushing on the nerve. at the junction of the
internal carotid and posterior communicating arteries.
A third nerve palsy involving the pupil must be assumed to be
secondary to an aneurysm until proven otherwise
Trochlear Nerve palsy
„ Trochlear Nerve (IV)---superior oblique muscle:
„ The fourth cranial nerve is the skinniest nerve and runs the longest distance
inside the cranial vault. This long passage makes it more susceptible to injury if
the brain sloshes around and bounces against the tentorium. The fourth nerve is
also susceptible to being pulled from the root where it exits from the back of the
brainstem. The long course also makes it susceptible to neoplasm.
„ 1/3rd Trauma
1/3rd Congenital
1/3rd Ischemic (diabetic)
„ 3-step test
Abducens palsy
„
„
„
„
Nasopharyngeal tumor
Acoustic neuroma
IICP, usually bilateral palsy Æ false localizing sign
Basal skull fracture
Cavernous sinus syndrome
„ III, IV, VI, V-1
„ Painful ophthalmoplegia
„ Eg. CC- fistula
tolosa-hunt syndrome
aneurysm
menigioma
Cavernous sinus syndrome