Last reviewed 01/2018

There are several circumstances where bilateral miosis may occur. These include:

  • pontine haemorrhage or tumour may cause bilateral miosis possibly by affection of both sympathetic pathways.
  • in infancy the pupils are often miotic.
  • in old people, senile miosis occurs as a result of fibrous replacement of the sphincter pupillae muscles. The pupils may be small and not readily dilated with mydriatics.