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.
Like other vessels, they, too, can be damaged by high blood pressure: Eye blood vessel damage (retinopathy). High blood pressure can damage the vessels supplying blood to your retina, causing retinopathy. This condition can lead to bleeding in the eye, blurred vision and complete loss of vision. If you also have both diabetes and high blood pressure, you're at an even greater risk.