What causes a Subconjunctal Haemorrage? If you don’t know it’s okay ;)

Question: What causes a Subconjunctal Haemorrage? If you don't know it's okay ;)
- Keywords:
  cause,
  subconjunctival haemorrhage
Asked by Spearofstiles to Deborah, Euan, Maheen, Rob, Stu on 17 Jun 2016.
- Maheen Siddiqui answered on 17 Jun 2016:
  
  It can be caused by a sudden increase in blood pressure that can result from heavy lifting, coughing, sneezing, laughing and constipation.
  
  I have actually had it twice! Once when I had really bad food poisoning and threw up so hard (sorry TMI) that I got bleeding in my eye. And another time my brother and I were messing around and he smacked my face and ended up hitting my eye!

Question: What causes a Subconjunctal Haemorrage? If you don't know it's okay ;)