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.
Last reviewed 01/2018