aetiology

Last reviewed 10/2022

The common causes of a squint are neurogenic:

  • III nerve palsy:
    • ptosis
    • dilated pupil unreactive to light
    • double vision present in all directions except for lateral gaze to the side of the lesion

  • IV nerve palsy:
    • double vision is maximal when looking down and in
    • doubling may be horizontal, vertical or tilted

  • VI nerve palsy:
    • horizontal diplopia maximal when looking to the side of the lesion

  • brainstem syndromes including:
    • internuclear ophthalmoplegia
    • one and a half syndrome
    • Weber's syndrome

Paralytic squints may be caused by:

  • head trauma
  • cerebrovascular disease
  • demyelinating disease
  • space occupying lesions:
    • tumour
    • haemorrhage
    • abscess
    • cerebral aneurysm
  • raised intracranial pressure
  • diabetes mellitus