immediate features of paralysis

Last reviewed 01/2018

The acute features of oculomotor nerve palsy may include:

• divergent strabismus:
• the paralysed eye is rotated outwards and downwards when the normal eye fixates - due to intact actions of lateral rectus and superior oblique muscles
• concurrent trochlear nerve palsy is indicated by absence of intorsion on attempted down-gaze

• only lateral movement is possible

• pupil may be fixed and dilated, and accommodation lost:
• however the pupil is spared in 75% of cases due to diabetes since the inner pupillary fibres are more affected than the outer ones

• ptosis of the upper eyelid - may cover the pupil due to loss of action of levator palpebrae superioris

• ipsilateral oculomotor nerve palsy may feature as part of Benedikt or Weber syndromes

• there may be a mild proptosis arising from loss of tone of three of the four recti muscles