Red eye is a common name for acute conjunctivitis with diverse and non-specific symptoms, including red and sore eyes, photophobia and tearing, foreign body sensation, itchy eyes, and increased secretions, which generally do not affect vision. ”Red eye” is the common name for acute conjunctivitis caused by infectious and epidemic pathogenic microorganisms. The typical symptoms are redness and pain in the eyes, photophobia and tearing, foreign body sensation, itchy eyes, and increased discharge. However, the clinical manifestations of acute conjunctivitis are diverse due to the different pathogenic bacteria that cause it, and red eyes are a common symptom of “pink eye”. (1) Acute conjunctivitis caused by viral infection is often accompanied by systemic symptoms of acute viral infection such as fever, sore throat, and swollen ear lymph nodes. Ocular discharge is watery, and in severe cases, pseudomembranes may appear. (2) Acute conjunctivitis with bacterial infection is characterized by mucus or purulent discharge, and the patient often feels an increase in “eye stool” that makes it difficult to open the eyes. (3) Trachoma caused by Chlamydia trachomatis infection, typical symptoms include varying degrees of lacrimation, eyelid redness, and swelling of the lymph nodes in front of the ear. Regardless of the pathogenic bacteria causing acute conjunctivitis, if the cornea is affected and causes keratitis, photophobia and eye pain can be significantly aggravated, and may also cause vision loss, so if there is persistent blurred vision, you should go to the hospital as soon as possible. In summary, the common symptoms of pink eye include red eyes and eye pain, photophobia and tearing, foreign body sensation, and increased secretion. Depending on the causative microorganism, the symptoms may vary in severity and severity.