Under normal condition, the blood vessels of eyeball conjunctiva are shriveled and in a state of "fast asleep", and there is no blood flowing in the vessels, so the sclera appears white. When the bacteria or virus intrude, the blood vessels wake up with a start and begin an eclasis, so the blood flows from all around, hence the red sclera. The most obvious symptom of the inflamed eyes is bloodshot. Suffering acute or chronic conjunctivitis, keratitis, iris eyelash inflammation, sclera inflammation, glaucoma, chemical burn of ocular region can give rise to different degrees of bloodshot in the eyes. Also, stress can cause bloodshot in the eye. Under this circumstance, you need to take a good rest to avoid the eye strain. But I advise you to go to the hospital for a thorough examination, after all, eye problem should be taken seriously.