My father has glaucoma, diagnosed 1 yr ago. 3 days ago he woke with blackeye. is it cause for concern and what happened?

See details: It is not a concern unless his vision is effected. There are several causes for this minor soft tissue bleeding.

Probably not: Glaucoma would not contribute to getting a black eye. A black eye usually occurs secondary to trauma which causes damage to blood vessels in the lids resulting in bleeding which appears dark. It should resolve without treatment in time.