You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Ulcus serpens is caused by and explain in detail?
Hypopyon corneal ulcer The characteristic hypopyon corneal ulcer caused by pneumococcus is called ulcus serpens. Source of infection: for pneumococcal infection is usually the chronic dacryocystitis. Clinical features: Signs: Typical features of ulcus serpens are: 1) Ulcus serpens is a greyish white or yellowish disc shaped ulcer occuring near the centre of cornea. 2) The ulcer has a tendency to creep over the cornea in a serpiginous fashion. One edge of the ulcer, along which the ulcer spreads, shows more infiltration. The other side of the ulcer may be undergoing simultaneous cicatrization and the edges may be covered with fresh epithelium. 3)Violent iridocyclitis is commonly associated with a definite hypopyon. 4)Hypopyon increases in size very rapidly and often results in secondary glaucoma.  5) Ulcer spreads rapidly and has a great tendency for early perforation. Ref:- A K KHURANA; pg num:-96