I had four surgeries in the other eye last june and both eyes were pressure tested. The injured one had a higher pressure but the other one (bloody one) was normal. It always clears up in 3-5 days but it looks really bad and I get tired of having to explain it to everyone that see's it. I have been tempted to get an eye patch and then nobody will ask any questions or make any assumptions.
Since I do alot of metal working I am sure it's from an old injury from metal fragments. I wear saftey glasses but that doesn't always keep every speck out.