If oedema occurs in the eyes, it is necessary to distinguish between unilateral and bilateral oedema. If unilateral, it is mainly caused by local factors, such as local eye lesions, allergies, as well as trauma or mosquito bites. If the edema is bilateral, it is necessary to exclude local factors such as allergies, e.g. drugs, certain cosmetics, or ocular diseases. Systemic diseases, such as kidney disease, liver disease, cardiovascular disease, and rheumatologic disease, should also be excluded. Kidney disease is often associated with bilateral edema of the lower extremities and increased foam in the urine. Liver disease is associated with jaundice of the eyes or face and a history of liver disease. Cardiac disorders are often associated with inability to lie down at night and palpitations after activity, while rheumatic disorders are often associated with facial erythema, mouth ulcers, and alopecia. Therefore, ocular edema needs to be distinguished as unilateral or bilateral, and if it is bilateral, it needs to be distinguished as to which systemic disease it is, and different diseases have their own characteristic manifestations at the same time.