Internuclear Ophthalmoplegia

Whereas double vision is a common symptom in multiple sclerosis, it is unusual to see an

Visual Fields

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Retina Optic nerve

Optic chiasma

Optic tract

Lateral geniculate body

Optic radiation

Figure 22.5. The visual pathway.!

Retina Optic nerve

Optic chiasma

Optic tract

Lateral geniculate body

Optic radiation

Occipital cortex

Figure 22.5. The visual pathway.!

obvious defect of the ocular movements. Sometimes it can be seen that one eye fails to turn inwards when the patient is asked to look to the opposite side, and yet when the patient is made to converge the eyes on a near object, the medial rectus moves normally. This failure of the muscle action with certain co-ordinated eye movements only (i.e., limitation of adduction),while the opposite abducting eye shows nystagmus, is termed "internuclear ophthalmoplegia". It is characteristic of multiple sclerosis when seen in young people (when the internuclear ophthalmoplegia is usually bilateral and is caused by a demyelinating lesion in the pons) but usually has a vascular cause in the elderly (when it is usually unilateral).

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