The main and common symptoms of keratitis are eye redness, eye pain, photophobia, vision loss, and discharge. When keratitis first starts, it is mostly characterized by ocular congestion, eye pain, photophobia, tearing, and eyelid spasms, which can be accompanied by mild symptoms of vision loss. In patients with severe keratitis, the bulbar conjunctiva and even the eyelids can become edematous. As the disease progresses, corneal transparency decreases and vision loss is further aggravated. Visual acuity may appear hairy, and when corneal ulcers appear, especially when the corneal ulcers are located in the center of the cornea, vision loss is significant. The symptoms of keratitis vary from one cause to another. Bacterial keratitis has the most acute onset and the most severe symptoms, with increased secretions and yellow mucous; viral keratitis is second, with little secretions, aqueous or mucous, and patients with herpes simplex viral keratitis may have reduced corneal perception; fungal keratitis patients often have the mildest symptoms of eye irritation and develop more slowly, and sometimes the corneal lesions are already severe, but the patient does not feel it The corneal lesions are grayish or yellowish-white in color and have a dry and rough appearance. The degree of involvement of vision after the ulcer heals depends mainly on the location of the scar, which not only prevents light from entering the eye, but also changes the curvature and refractive power of the corneal surface, creating irregular astigmatism and preventing objects from being imaged clearly on the retina. In summary, the main symptoms of keratitis are eye irritation and vision loss, and timely treatment can improve the prognosis to some extent.