The common causes of yellow eyeballs include blepharospasm, hyperpigmentation, and diseases of the hepatobiliary system. 1. Blepharospasm: It is a grayish-yellow bulbous conjunctival nodule elevated at the connection of the angle scleral margin in the blepharospasm area, which is usually induced by stimulation of ultraviolet rays and other external factors. 2. Pigmentation: it is because the conjunctival tissue is exposed to the outside world and easily stimulated by various chemical and physical factors, and at the same time, the yellowing of conjunctiva is caused by age factor and metabolic abnormality which leads to conjunctival pigmentation. 3. Hepatobiliary system diseases: yellow eyes may also be caused by hepatobiliary system diseases, such as hepatitis B, bile duct obstruction, etc., which will cause elevated bilirubin in the blood, thus leading to scleral yellowing, making the eyes look yellow. The presence of yellow eyeballs, if accompanied by other discomforts of the organism, it is recommended to go to the hospital in time for examination and treatment.