Red eye generally refers to acute or subacute bacterial conjunctivitis, also known as acute cicatricial conjunctivitis, commonly known as pink eye. Common causes are due to pathogen infections, such as Staphylococcus aureus, Diplococcus pneumoniae, and Haemophilus influenzae. 1. Staphylococcus aureus: Mostly Staphylococcus aureus infections cause conjunctival congestion with red eyes. Most of them are accompanied by blepharitis, and it is difficult to open the eyes in the morning due to mucopurulent secretion that clogs the eyes. 2. Pneumococcus: Pneumococcus infection is self-limiting and has a higher incidence in children than in adults. Pneumococcal infection causes conjunctival congestion, mucopurulent discharge and other symptoms, upper lid conjunctiva and vault conjunctiva may have subconjunctival hemorrhage, bulbar conjunctival edema. 3. Haemophilus influenzae: the most common pathogen in bacterial conjunctivitis in children, 80% of adults can be seen in the upper respiratory tract Haemophilus influenzae symbiosis. Haemophilus influenzae infection will cause conjunctival congestion in addition to conjunctival hemorrhage, but also lead to bulbar subconjunctival hemorrhage, accompanied by purulent or mucopurulent secretions. Therefore, it is important to pay attention to personal hygiene to avoid the transmission of red eye. Contact lens users should clean their hands when wearing and removing contact lenses, and not share towels, etc. When acute conjunctivitis occurs, prompt medical attention and targeted management or treatment is recommended.