Keratitis is a common clinical ophthalmic disease. It is mainly caused by infection of the eye by pathogenic microorganisms such as bacteria, viruses, and fungi. If keratitis is not treated promptly, it may lead to blindness, so it is important to understand the symptoms and manifestations of keratitis. Since keratitis is an inflammatory disease that occurs at the cornea, most patients will experience eye redness, eye swelling, and eye pain. Photophobia, tearing, eyelid spasm, foreign body sensation, and vision loss are also typical clinical manifestations of keratitis. Depending on the cause of keratitis, there are four types of keratitis: bacterial keratitis, fungal keratitis, viral keratitis, and amoebic keratitis. The clinical manifestations of these four types of keratitis have commonalities as well as their own characteristics. Bacterial keratitis is characterized by acute, severe, and rapid onset of symptoms. Viral is characterized by relatively mild symptoms compared to bacterial, but the onset of the disease is often preceded by a cold, and viral keratitis has a high recurrence rate. Fungal is characterized by symptoms that do not match the condition. Patients have very mild symptoms and almost no obvious pain, but when examined by a doctor, the corneal lesions are very serious, often manifested by corneal perforation and pus accumulation in the anterior chamber. Therefore, once symptoms such as eye redness and vision loss are detected, you should immediately go to the hospital, otherwise it will lead to complications such as corneal scarring, corneal edema, corneal perforation, and even cause irreversible vision impairment, leading to the occurrence of blindness and causing great harm to the physical and mental health of patients. Eye redness, eye pain, photophobia, lacrimation, and vision loss are typical symptoms of keratitis. Once these symptoms appear, timely and standardized treatment can prevent complications and shorten the course of the disease.