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THE MERCK MANUAL MEDICAL LIBRARY: The Merck Manual of Medical Information--Home Edition
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Superficial Punctate Keratitis

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Superficial punctate keratitis is death of cells on the surface of the cornea.

The cause of this disorder may be a viral infection, a bacterial infection (including trachoma (see Conjunctival and Scleral Disorders: Trachoma), dry eyes, strong chemicals splashed in the eye, exposure to ultraviolet light (sunlight, sunlamps, or welding arcs), irritation from prolonged use of contact lenses, or irritation from or an allergy to eye drops. The disorder can also be a side effect of certain drugs taken by mouth or intravenously.

In superficial punctate keratitis, the eyes are generally painful, watery, sensitive to bright light, and bloodshot, and vision may be slightly blurred. Often there will be a burning, gritty feeling or a feeling as if a foreign object is trapped in the eye. When ultraviolet light causes the disorder, symptoms usually do not occur until several hours after exposure; they last for 1 to 2 days. When a virus causes the disorder, a lymph node in front of the ear on the affected side may be swollen and tender.

The diagnosis is based on the symptoms, on whether the person has been exposed to any of the known causes, and on an examination of the cornea with a slit lamp (see What Is a Slit Lamp?Figures).

Almost everyone who has this disorder recovers completely. When the cause is a virus, (other than herpes simplex or herpes zoster [shingles]), no treatment is needed, and recovery usually occurs within 3 weeks. When the cause is a bacterial infection or contact lens irritation, antibiotics are used. When the cause is dry eyes, ointments and artificial tears (eye drops prepared with substances that simulate real tears) are effective. When the cause is exposure to ultraviolet light, an antibiotic ointment, an eye drop that dilates the pupil (see Eyelid and Tearing Disorders:CanaliculitisFigures), and an eye patch may provide relief. And when the cause is a drug reaction or irritation from allergy to eye drops, the drug or eye drops must be discontinued.

Last full review/revision February 2003

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