Conjunctivitis is not the same as periostitis, the difference is in the cause of the disease, the site of injury, clinical symptoms and other aspects. 1. Etiology: Conjunctivitis is an inflammation of the conjunctiva caused by microbial infections such as viruses and bacteria, external stimuli and allergic reactions, and is also known as “red eye”. Osteochondritis dissecans is an inflammatory reaction caused by the pulling of periosteal tissue covering the bone surface, bacterial infection, tumor invasion and other factors. 2. Site of injury: Conjunctivitis is an inflammation caused by infection of the conjunctival tissue of the eye. And periostitis is the periosteal tissue that covers the surface of bones all over the body. 3. Clinical symptoms: Conjunctivitis causes conjunctival edema, conjunctival discharge, papillary hyperplasia, and swollen lymph nodes behind the ear. Osteochondritis dissecans may cause tissue swelling, localized congestion and edema, localized pain, and pain on pressure. The symptoms associated with conjunctivitis or osteochondritis need to be actively consulted and treated appropriately in accordance with medical advice.