The white of the eye, commonly referred to as the white of the eye, is medically known as the sclera, which is also covered by a clear layer of the bulbar conjunctiva. Under normal circumstances, both the conjunctiva and scleral tissues are covered with a network of capillaries, so they are visible when normal. However, if the blood vessels are abnormally dilated, tortuous and dark in color, it may be a pathological phenomenon. The essence of this is what is known medically as “congestion”. Common causes of bloodshot whites are inflammation, trauma, foreign body irritation, etc. Common inflammatory conditions such as conjunctivitis, sclicitis, keratitis, and iridocyclitis can all cause blood in the white of the eye. Trauma to the eye can also cause localized blood congestion in the eye. Wind and sand irritation or chemicals entering the tears, or other foreign bodies entering the tears, can also cause congestion. Some people because of poor rest and sleep, prolonged overuse of the eyes, long-term exposure to electronic products, can also cause an increase in the blood in the white of the eyes, a condition that is generally common in signs of fatigue. Frequent smokers and drinkers, as alcohol and its metabolites enter the bloodstream, can lead to vasodilatation throughout the body, which can also lead to increased white blood in the eyes. In conclusion, blood vessel congestion on the surface of the eye can be a normal physiological state or an abnormal pathological state. The physiological state is mainly related to the number of blood vessels in the eye itself and eye habits, while the pathological state is commonly caused by eye lesions or other diseases that cause irritation.