keratitis

Keratitis is an inflammation or infection of the cornea, the clear front surface of the eye. It can affect one or both eyes and may threaten vision if not promptly treated. Keratitis can be infectious or noninfectious, and the outcome depends on the cause, the severity of corneal involvement, and timely management.

Infectious keratitis is caused by bacteria, viruses, fungi, or protozoa. Bacterial keratitis is commonly associated with contact lens wear or trauma and can involve organisms such as Staphylococcus, Streptococcus, or Pseudomonas. Viral keratitis most often results from herpes simplex virus or varicella-zoster virus. Fungal keratitis may follow eye injury with organic material, and fungi such as Candida, Aspergillus, or Fusarium can be involved. Acanthamoeba keratitis is a rare but serious protozoal infection linked to contact lens use and contaminated water.

Noninfectious keratitis includes exposure keratopathy from eyelid or corneal surface disorders, chemical or thermal injuries, dry eye, autoimmune diseases, or adverse reactions to medications.

Symptoms typically include eye redness, pain, photophobia, tearing, blurred vision, discharge, and a foreign-body sensation. Severe cases may show corneal thinning or perforation. Diagnosis relies on clinical examination with slit-lamp biomicroscopy, fluorescein staining, and microbial cultures or PCR when infection is suspected.

Treatment varies by cause. Bacterial keratitis is treated with topical antibiotics; viral keratitis with antivirals; fungal keratitis with antifungal agents; Acanthamoeba keratitis requires long-term topical antiseptics. Corticosteroids may be used cautiously in selected cases under specialist supervision. Prevention focuses on good contact lens hygiene, eye protection, prompt treatment of ocular surface issues, and avoiding contaminated water exposure.