High Blood Pressure and Blood In Eye?

My friend all of a sudden has severe broken blood vessels in her eyes. She didnt sneeze, cough, fall, get hit or anything. She went to the ophthalmologist and he said her eyes were fine (no infection) but when he took her blood pressure it was extremely high. She is usually perfectly healthy and only 21. Is the high blood pressure a cause of the broken blood vesels in her eye? And why would this all of a sudden happen?