Keratitis can cause pain in the eye because the cornea is more sensitive and its nerves are more abundantly distributed. Most keratoconjunctivitis is primarily an infiltration of the epithelium or stroma, whether it is the epithelium or the stroma, which can cause damage to the cornea. This damage results in increased nerve sensitivity and pain, which is accompanied by conjunctival congestion in the periphery of the black eye. Usually, the closer to the periphery of the conjunctiva, the greater the congestion, and the closer to the black eye, the heavier the congestion, which is typical of damage to the corneal layers. Therefore, keratitis requires aggressive symptomatic treatment according to the disease, as it may be caused by a virus or due to an immune response, so medication needs to be used according to the situation in order to avoid damage to the vision.