Any object or substance that enters the eye is a foreign body. It could be dust, a metal object, cosmetics and so on. Foreign bodies are likely to be found on the conjunctiva (a thin membrane that lines the outer surface of the eye). They can also be found on the cornea (clear, dome-shaped surface at the front of the eye).
Foreign bodies affect both genders and can occur at any age. The most common types of foreign bodies on the conjunctiva include dust, dirt, cosmetics, contact lenses and sand. Those affecting the cornea include pieces of metal, glass, sand, wood or plastic. Foreign bodies can move around, lie under the eyelid or be stuck on the eye’s surface.
- Extraocular foreign bodies - Affect the lid, conjunctiva, sclera and cornea. They do not penetrate the eye. These are the most common.
- Intraocular foreign bodies - Found in the angle of the anterior chamber, vitreous, iris, intraorbital and retina. These are penetrating ocular injuries often due to workplace accidents.
Causes and Risk Factors
Foreign bodies in the eye may occur when objects enter during the normal day to day activities. Intraocular objects may find their way in through high speeds like in explosions or accident scenes.
Anybody is at risk of having a foreign body in the eye. However, those at a higher risk are people who work with tools like hammers and chisels.
Signs & Symptoms
Harmless foreign bodies prompt individuals to rub their eyes. It is advisable to avoid rubbing the eye. Most of the time tears will wash the foreign body to the corner of the eye removing the discomfort. However, those foreign bodies that remain or scratch the eye may present the following symptoms:
- Red and watery eye
- A feeling of something in the eye
- Pain during blinking
- Burning in the eye or irritation
- Blurred vision or loss of vision in the affected eye
- Increased sensitivity to bright light
- A scratchy feeling when one blinks
- In extraocular objects, there may be blood or fluid from the eye
Symptoms may manifest immediately or after about 8 hours or so.
Prompt diagnosis and treatment are necessary to prevent infection and loss of vision. The eye professional will examine the history behind the foreign body. The following can be done immediately:
- A dilated examination after dropping anesthesia in the eye
- Examining the iris before dilation to check for perforating injury
- Close examination of the natural lens after dilation
- A complete examination of both eyes even if the other one is not affected
- Careful examination of the eyelids and eyebrows
- A slit lamp examination to locate a foreign body in the anterior segment
- A fluorescein stain to establish an abrasion in the cornea
- Imaging to determine the presence of an intraocular object
Treatment of is directed towards removing the foreign bodies that exists in the eye.
Treatment depends on whether the object is extraocular or intraocular. The following may be done:
- The eye may be washed in saline to flush out objects like dust or dirt. A small cotton applicator can also remove the object
- The foreign body can be removed using a needle with a binocular device
- Paracetamol may be prescribed in case of pain
- An antibiotic ointment may be placed in the eye
- An X-ray is needed if the object has entered the eyeball
- The eye doctor will place a patch over the eye to give it time to heal. This happens with corneal abrasions. The patch should last for 12 to 24 hours
- The doctor may give a tetanus injection
Some intraocular cases might require surgery. The surgical techniques used depend on the size and composition of the object. Surgery is conducted using techniques such as limbal incision and viscoelastic solution for the anterior chamber. Pars plana vitrectomy (PPV) is used for foreign bodies in the posterior chamber.
Some minor cases of foreign bodies can be treated at home through:
- Washing hands with soap and water
- Flushing out the object with a gentle stream of warm water using an eyecup or a shower. Holding the eyelid open, aim the shower over the forehead.
- Removing the contact lenses when washing the eye. Sometimes the object may be lying on the contact lens.
However, in severe cases, no attempt should be made to remove the foreign body. If the object is as described below, medical attention should be sought immediately:
- So large the individual can’t close their eyes
- Has rough or sharp edges
- Lodged in the eye
- Causes bleeding in the eye
- Entered the eye at high speed
- Contains chemicals or is rusty
The patient should do the following after treatment:
- Wash hands before using the drugs prescribed
- Follow the doctor's advice on medication and home care
- Avoid the use of contact lenses until the eye is healed
Frequent postoperative examinations are needed. They check for major complications like retinal detachment and anterior segment injuries.
Poor visual outcomes could arise due to many factors. One of them could be the extent of the injuries. Another is the emergency treatment the patient received; whether the diagnosis was immediate and accurate.
Foreign objects can cause infection inside the eye (endophthalmitis). For example, organic objects like vegetable matter can cause infection. The rust in metallic objects may cause a scar which can interfere with vision. These can lead to poor vision outcomes if left untreated.
People who work in industrial settings or use machines like lawn mowers should ensure they wear eye safety glasses.
Avoid standing or sitting in places where there is grinding or drilling taking place.