This is called subconjunctival haemorrhage. There is accumulation of blood under the layer of eye called conjunctiva. This may occur due to trauma to the eye, vigorously rubbing the eye or may occur due to high blood pressure. Nothing to worry about.... It resolves on its own... Bit it will take nearly 2 to 3 weeks for the blood to get absorbed completely.

This kind of problem are common in hypertensive patient Here minor blood vessel of superficial conjunctiva gives away due to high BP Best thing is Its self resolving condition with few medication