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For further information, see CMDT Part 7-09: Infectious Keratitis
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Important categories of infectious keratitis include bacterial, herpetic, fungal, and amoebic
Bacterial keratitis
Herpes simplex keratitis
An important cause of ocular morbidity
The ability of the virus to colonize the trigeminal ganglion leads to recurrences that may be precipitated by fever, excessive exposure to sunlight, or immunodeficiency
Herpetic corneal disease is typically unilateral but can occur bilaterally in the setting of atopy or immunocompromise
Herpes zoster ophthalmicus
Frequently involves the ophthalmic division of the trigeminal nerve
Long-term complications
Optic neuropathy, cranial nerve palsies, acute retinal necrosis, and cerebral angiitis occur infrequently
HIV infection is an important risk factor and increases the likelihood of complications
Fungal keratitis
Tends to occur after corneal injury involving plant material or in an agricultural setting, in eyes with chronic ocular surface disease, and in contact lens wearers
Usually an indolent process
Amoebic keratitis
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