γγ1. Herpes simplex virus keratitis: this is a very common keratoconus lesion that often leads to severe visual impairment due to its recurrence and is the first blinding disease of keratoconus, which is extremely dangerous; 2. Superficial punctate keratitis: this is caused by the degeneration and shedding of epithelial cells and infiltration of inflammatory cells in the most superficial layer of the cornea. Most patients with superficial punctate keratitis have mild symptoms that they can feel themselves, sometimes with mild intraocular foreign body sensation, photophobia and tearing. The white conjunctiva next to the cornea is not red, and the corneal surface appears dotted with grayish-white cloudiness; 3, fungal keratitis: due to the widespread use of antibiotics and glucocorticoids the incidence of this fungal-induced infectious keratopathy has increased significantly and has become a highly blinding infectious eye disease. Patients have the main conscious symptoms of keratitis, but the onset is relatively slow and the course of the disease often lasts several months; 4, bacterial keratoconus: is a very serious purulent keratitis, often due to bacterial infection after corneal trauma, contact lens scratches or removal of corneal foreign body surgery.γγThe above introduces you to the classification of keratoconus. The main role of the cornea is similar to that of a lens in a camera, refracting and focusing the light coming into the eye on the retina to identify the shape and color of objects. Based on these roles, the cornea must remain optically clear and clean spherically.