[4] In developing countries, children afflicted by vitamin A deficiency are at high risk for corneal ulcer and may become blind in both eyes persisting throughout life.

[2] Among them are bacteria (including Chlamydia trachomatis), fungi, viruses, and protozoa:[3] Superficial ulcers involve a loss of part of the epithelium.

[2] Central ulcers are typically caused by trauma, dry eye, or exposure from facial nerve paralysis or exophthalmos.

Entropion, severe dry eye and trichiasis (inturning of eyelashes) may cause ulceration of the peripheral cornea.

Corneal ulcers are painful due to nerve exposure, and can cause tearing, squinting, and vision loss of the eye.

An axon reflex may be responsible for uveitis formation—stimulation of pain receptors in the cornea results in release inflammatory mediators such as prostaglandins, histamine, and acetylcholine.

However, larger or deeper ulcers often require the presence of blood vessels to supply inflammatory cells.

Diagnosis is done by direct observation under magnified view of slit lamp revealing the ulcer on the cornea.

Doing a corneal scraping and examining under the microscope with stains like Gram's and KOH preparation may reveal the bacteria and fungi respectively.

Bacterial corneal ulcer require intensive fortified antibiotic therapy to treat the infection.

Viral corneal ulceration caused by herpes virus may respond to antivirals like topical acyclovir ointment instilled at least five times a day.

Alongside, supportive therapy like pain medications are given, including topical cycloplegics like atropine or homatropine to dilate the pupil and thereby stop spasms of the ciliary muscle.

Loose epithelium and ulcer base can be scraped off and sent for culture sensitivity studies to find out the pathogenic organism.

In case of progressive or non-healing ulcers, surgical intervention by an ophthalmologist with corneal transplantation may be required to save the eye.

In all corneal ulcers it is important to rule out predisposing factors like diabetes mellitus and immunodeficiency.