Red patches on the eye are bulbar conjunctival hemorrhage. Bulbar conjunctival hemorrhage is commonly caused by rupture of blood vessels in the bulbar conjunctiva caused by forceful eye rubbing, coughing, sneezing, trauma, or vomiting. It is also caused by systemic diseases such as hypertension, diabetes and arteriosclerosis, which increase the permeability of blood vessels. Bulbar conjunctival hemorrhage occurs in winter, when the brittleness of blood vessels increases and their elasticity decreases, making it easier to bleed.