Corneal Foreign Body and Corneal Abrasion

 A 28-year-old man felt something fly into his eye while he was using a table saw without wearing protective eye gear. He presented with pain, tearing, photophobia, and thought that something was still in his eye.
On examination with a slit lamp, the physician noted that he had a wood chip that had penetrated the cornea (See pictures below)

                                Wood chip is visible in the cornea on close inspection of the eye.
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                          Slit-lamp examination reveals this wood chip has penetrated the cornea.

He was referred to an ophthalmologist who successfully removed the foreign body. He was treated with a short course of topical NSAIDs for pain relief, and had complete healing.

Case Discussion:

Corneal Foreign Body and Corneal Abrasion

Introduction: Corneal abrasions are often caused by eye trauma and can cause an inflammatory response. Corneal abrasions are detected using fluorescein and a UV light. A corneal foreign body can be seen during a careful physical examination with a good light source or slit lamp.
Nonpenetrating foreign bodies can be removed by an experienced physician in the office using topical anesthesia. Refer all penetrating foreign bodies to an ophthalmologist.

Pathophysiology: The cornea overlies the iris and provides barrier protection, filters UV light, and refracts light onto the retina.
• Abrasions in the cornea are typically caused by direct injury from a foreign body, resulting in an inflammatory reaction.
• The inflammatory reaction causes the symptoms and can persist for several days after the foreign object is out.

History and Physical Examination:
• History of ocular trauma or eye rubbing (although corneal abrasions can occur with no trauma history).

• Symptoms of pain, eye redness, photophobia, and a foreign-body sensation.
• Foreign body seen with direct visualization or a slit lamp
• Fluorescein application demonstrates green area (which represents the disruption in the corneal epithelium) under cobalt-blue filtered light
• History of contact lens wear.
• History of ocular or perioral herpes virus infection.

Differential Diagnosis: 
• Uveitis or iritis—Usually unilateral 360-degree perilimbal injection, eye pain, photophobia, and vision loss.
• Keratitis or corneal ulcerations—Diffuse erythema with ciliary injection often with miosis; eye discharge; pain, photophobia, and vision loss depending on the location of ulceration  There is often a history of trauma, herpes simplex virus (HSV), or contact lens wear. Patients should see an ophthalmologist urgently.
• Conjunctivitis—Conjunctival injection; eye discharge; gritty or uncomfortable feeling; no vision loss, history of respiratory infection, or contacts with others who have red eyes
• Acute-angle closure glaucoma—Cloudy cornea and scleral injection; eye pain with ipsilateral headache; severe vision loss, acutely elevated intraocular pressure.

Management: 
• Confirm diagnosis with fluorescein and a UV light (for abrasion) if no foreign body is readily visible.
• Carefully inspect for a foreign body. Invert the upper eyelid for full visualization. Slit-lamp visualization may be needed to determine if the cornea has been penetrated.
• Remove (or refer for removal) non penetrating foreign bodies. Apply a topical anesthetic, such as proparacaine or tetracaine. Remove with irrigation, a wet-tipped cotton applicator, or a finegauge needle.
• Remove contact lenses until cornea is healed
• Avoid patching in corneal abrasions smaller than 10 mm; it does not help.
• Prescribe ophthalmic NSAIDs for pain if needed
• Consider topical antibiotics. Chloramphenicol ointment reduced the risk of recurrent ulcer in a prospective, nonplacebo, controlled trial. Although chloramphenicol is rarely used in the United States, other ophthalmic antibiotics, such as erythromycin ointment, are used for corneal abrasions.