Poison ivy is all green. The stem of poison ivy is brown and cylindrical, while blackberry and raspberry stems can be green, can be squared in cross-section, and can have prickles. Raspberries and blackberries are never truly vines; that is, they do not attach to trees to support their stems.
Occasionally, these blood vessels can burst and led to hemorrhage (bleeding) that appears as a red patch on the white of the eye. In the majority of cases, this type of bleeding (called subconjunctival hemorrhage) occurs without a known cause. Subconjunctival hemorrhage can also result from certain medical conditions including trauma, high blood pressure, eye infections, and bleeding disorders. The straining associated with vomiting, coughing, or sneezing can also sometimes lead to subconjunctival hemorrhage. Stress is not a recognized cause of subconjunctival hemorrhage. The good news is, if you had a conjunctival hemorrhage, these are only cosmetically annoying but go away and do not endanger the vision.
1 The small blood vessels within the conjunctiva may break spontaneously or from injury, causing a red area on the sclera, resulting in a subconjunctival hemorrhage.  A subconjunctival hemorrhage appears as a bright red or dark red patch on the white of the eye.