Blood on the white of the eye
A sudden dark area of blood on the white of the eye is called a subconjuctival hemorrhage, and is actually a bruise caused by a broken blood vessel. The membrane or skin that covers the eye is transparent so that when a blood vessel breaks, the red blood is dramatically evident. This condition is painless, safe and not sight threatening although it can be cosmetically disturbing. The blood will resolve in a number of days and no treatment is needed. Artificial tears and warm compresses may help to make the eye more comfortable until it resolves. Contact an optometrist or ophthalmologist for more information