The cornea is normally a nearly invisible, clear structure covering the iris of the eye. Its two purposes are to transmit and focus the light entering the eye.

Causes of cloudy cornea include:

• Chemical burns to the cornea
• Herpetic keratoconjunctivitis (a form of conjunctivitis caused by herpes simplex )
• Infectious diseases
• Poor nutrition
• River blindness (onchocerciasis -- an infection common in parts of Africa)
• Several rare inherited diseases involving abnormal metabolism
• Sjogren syndrome
• Trachoma
• Trauma
• Vitamin A deficiency

Clouding leads to varying degrees of vision loss .

Consult your health care provider. There is no appropriate home care.

Contact your health care provider if:

• The outer surface of the eye appears cloudy
• You have trouble with your vision

Note: It is appropriate to see an ophthalmologist for vision or eye problems. However, your primary health care provider may also be involved if a whole-body (systemic) disease is suspected.

The doctor will take a medical history and examine your eyes.

Medical history questions may include:

• Did the cornea become cloudy quickly, or did it develop slowly?
• When did you first notice this?
• Does it affect both eyes?
• Is there any history of injury to the eye?
• What other symptoms do you have?
• Do you have any trouble with your vision?
• If so, what type (blurring, reduced vision, or other) and how much?

Physical examination will include a thorough check of your eyes and vision.

Diagnostic tests may include:

• Biopsy of lid tissue
• Ophthalmoscopy
• Special photographs to measure the cells of the cornea
• Standard eye exam
• Tests for suspected causes
• Ultrasound to measure corneal thickness

After seeing your health care provider:

You may want to add a diagnosis related to cloudy cornea to your personal medical record.

Crouch JR ER, Crouch ER, Grant T. Ophthalmology. In: Rakel RE. Rakel: Textbook of Family Medicine. 7th ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 53.

Brunette DD. Ophthalmology. In: Marx JA. Marx: Rosen's Emergency Medicine: Concepts and Clinical Practice. 6th ed. Philadelphia, Pa: Mosby; 2006: chap 70.

Newlin AC, Sugar J. Corneal and External Eye Manifestations of Systemic Disease. In: Yanoff M, Duker JS, Augsburger JJ, Azar DT. Yanoff: Opthalmology. 2nd ed. Philadelphia, Pa: Mosby; 2004: chap 66.