Unit 2: Visual field defects, double vision & optic disc swelling

• The 4^th (Trochlear) cranial nerve supplies the superior oblique muscle .
• The primary action of the superior oblique is rotation of the eye towards the nose (intorsion)

Differential diagnosis of the causes of a 4th nerve palsy:

A superior oblique palsy can be:

• Unilateral or bilateral
• Congenital or acquired
• Diabetes or hypertension
• Demylinating diseases e.g. Multiple Sclerosis
• Giant cell arteritis
• Tumours
• Aneurysms

Symptoms

Acquired diplopia

Signs

Abnormal head posture (head tilted away from side of lesion) and the eye deviating upwards as it moves towards the nose.

Treatment

• Children Treat any amblyopia and correct refractive error
• Prisms May benefit depending on orthoptic assessment
• Surgery To improve diplopia and occasionally for cosmetic reasons
• Follow up As appropriate