Under normal circumstances the white of our eyes (clinically known as the sclera) is covered with a layer of conjunctiva although the capillaries are very dense, under normal circumstances, the sclera appears white porcelain white, the surface of the transparent conjunctiva can be seen in the tiny blood vessels once stimulated in some way, the blood vessels immediately wake up, expansion, blood swarming, the surface of the sclera is also red up manifested as eye congestion. Various reasons for sclera and conjunctiva stimulation can lead to eye congestion as follows: 1, excessive use of the eyes: long time to look at the computer screen and cell phone eyes blink less often, resulting in the evaporation of the tear film on the surface of the eye, thinning, and even rupture, the protective effect on the eyes is weakened, foreign body stimulation is easy to become red. 2, allergic reactions: all kinds of foreign bodies into the eyes can lead to eye allergies, congestion. The main manifestation of allergic conjunctivitis is eye itching and congestion. 3, inflammatory infections: acute and chronic conjunctivitis, various keratitis, sclerenitis, when the invasion of bacteria and viruses can be manifested to varying degrees of congestion. 4, trauma: external damage to stimulate the conjunctiva, sclera, etc. can lead to congestion. For example, light irritation burns caused by welding, etc. 5, systemic diseases: thrombocytopenia, aplastic anemia, leukemia and other hematologic diseases resulting in abnormal coagulation mechanisms. Diabetes, hypertension, and kidney disease can also manifest as eye congestion. In addition, glaucoma, excessive alcohol consumption, some drugs can also lead to eye congestion, as long as the irritation of the eye sclera, conjunctiva, etc. can lead to eye congestion and redness, such situations we had better go to the hospital for examination, usually we should also pay attention to protect our “window to the soul”, avoid excessive use of the eyes.