A corneal foreign body is an external type of eye disorder that occurs when a foreign object is lodged in the cornea. The foreign body may be embedded in or loosely attached to the cornea. 

The cornea is exposed to foreign objects because it is the most anterior part of the eye. 
Often, foreign matter enters the cornea as a result of any eye trauma occasioned by accident. The common foreign objects that may be lodged in, or around the cornea include sand, metal, wood, glass, plastic, and organic matter.

Sand may enter the cornea because of wind. Chopping wood may cause a piece to fly off and enter the eye. A small bit of metal can get stuck in the cornea in during metal works. 

While blinking and tearing removes foreign matter from the eye, at times materials get lodged in the cornea. The foreign object can cause scratches on the cornea and lead to eye inflammation. Thus, it is crucial that it is removed and treated to prevent an eye infection or in extreme cases, vision loss.

Also Known As

Corneal FB

Causes and Risk Factors

Many activities may expose an individual to the risk of a foreign material getting into the eye. These include: 

  • Using equipment such as a wood saw or metal grinder  
  • Using a snow blower or mowing the lawn, and accidentally going over a stick or stone
  • Working on ceiling tiles and other materials that lie above an individual
  • Working under a car 
  • Outdoor activities

Signs & Symptoms

The symptoms of a foreign object in the cornea include:

  • Foreign body sensation in the eye
  • Continuous irritation
  • Eye pain
  • Excessive tearing
  • Light sensitivity
  • Decreased vision

The signs include:

  • Redness
  • Visible cornea foreign object
  • Fluorescent stains in the cornea around the foreign material 
  • Corneal rust ring from a metal object
  • A subconjunctival hemorrhage may occur


Where a foreign body is embedded in the cornea, the eye professional must get a thorough history. It helps professionals to prepare and provide the appropriate eye care. 

The eye physician needs to know the mechanism of the injury to assess the force with which the foreign matter entered the cornea. It also helps to determine the need for any special tests to investigate any potential ocular perforation and intraocular foreign objects.

The professional examines the eye using a slit lamp microscope. It enables them to locate the foreign matter and determine how deep it is lodged in the cornea.

In severe cases, imaging studies such as ultrasound, X-rays, or CT scans may be used to assess the inside of the eye further.


Treatment is aimed at removing the foreign body from the cornea.

Medical Treatment

It is highly recommended that a foreign body is removed in a doctor’s office or an emergency room. The eye physician may prescribe ointment or antibiotic eye drops to prevent or treat eye infection and help with the healing.

Surgical Treatment

Extreme caution must be exercised when removing an embedded foreign object from the cornea. The surgeon uses needles and other instruments to extract the foreign object.

Home Care

If one suspects that they have a foreign object in the eye, they should take the following precautions:

  • Avoid rubbing or putting pressure on the eye
  • Avoid using any utensils or implements on the eye
  • In case the person is wearing contact lenses, they should not remove them unless they have suffered a chemical injury or there is a sudden swelling
  • It is essential to get immediate treatment to avoid infection or even damaged vision.

Prognosis/Long-term outlook

A foreign body in the cornea can lead to eye inflammation, infection, scarring and loss of vision.  Every foreign object in the eye is removed as soon as possible; unless removing it may lead to more significant damage.

After the removal of the foreign body from the cornea, the patient should be checked in 24 hours to asses the cornea for any possible infections, epithelial and edema defects. The exact post-procedural care and follow-up depend on the nature and depth of the foreign body.

Prevention/Follow Up

Where there is a risk of an eye injury, one should wear protective eyewear. It prevents foreign bodies from entering the cornea. 
It is especially important to wear protective eye gear during outdoor activities as wind can blow small particles into the eye. 
One must also use protective eyewear for hazardous undertakings such as metal and wood works.