The common cause of red eyes is caused by eye fatigue on the one hand; on the other hand, it can be considered to be common eye inflammation, foreign body irritation, and so on. 1. Eye fatigue: eye fatigue caused by prolonged viewing of electronic products such as cell phones or computers, which leads to conjunctival congestion, so you will see the phenomenon of red eyes. 2. Eye inflammation: conjunctivitis is caused by microbial infection or physical and chemical factors, allergic reactions, in addition to the redness of the eyes, there will be an increase in eye secretions, foreign body sensation, burning sensation and other uncomfortable symptoms. Iridocyclitis is caused by infectious factors and autoimmune factors, trauma and physical and chemical damage, etc., which can also lead to red eyes, with photophobia, tearing and other irritating symptoms. 3. Eye foreign body irritation: mostly due to flying insects, dust and other foreign bodies into the eyes, causing friction in the eyes so that the eyes appear red, congestion, pain and other symptoms. There are many reasons for the redness of the eyes, and when the symptoms persist and cannot be relieved by rest, it is recommended to consult a doctor in a timely manner to clarify the cause and follow the doctor’s instructions for standardized treatment, so as to avoid delaying the condition.