4 Neuro-ophthalmology

Anatomy of the Visual Pathway

Optic nerve → chiasm → optic tract → lateral geniculate body → optic radiation → occipital lobe (Figure 4-1)

Optic nerve

composed of 1.2 million nerve fibers; approximately 1.5 mm in diameter, enlarges to 3.5 mm posterior to lamina cribrosa due to myelin sheath; located 3–4 mm from fovea; causes absolute scotoma (blind spot) 15° temporal to fixation and slightly below horizontal meridian; approximately 45-50 mm in length (1 mm intraocular, 25 mm intraorbital, 9 mm intracanalicular, 10–15 mm intracranial) (Figure 4-2); acquires myelin posterior to lamina cribosa

Other areas



Visual Field (VF) Defects (Figure 4-9)


Neurologic VF defects

Eye Movements under Supranuclear Control

Nonoptic reflex systems

integrate eye movements with body movements

Eye Movement Disorders

Horizontal Gaze Palsies


Vertical Gaze Abnormalities


Rhythmic involuntary oscillations of the eyes due to disorder of SEM system. Direction named after fast phase (brain’s attempt to correct problem), even though abnormality is noted with slow phase

Acquired Nystagmus

Pattern helps localize pathology, may have oscillopsia

Cranial Nerve Palsies (FIGURE 4-16)

Oculomotor Nerve (CN 3) Palsy

7 syndromes (Figure 4-17)

Jun 4, 2016 | Posted by in OPHTHALMOLOGY | Comments Off on Neuro-ophthalmology
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