Foreign Body in the Eye
	What is a foreign body in the eye? Any material such as dust, sand or paint which gets into the eye is called a foreign body. Foreign bodies fall into two important categories Superficial foreign bodies These stick to the front of the eye or get trapped under one of the eyelids, but do not enter the eye. Penetrating foreign bodies These penetrate the outer layer of the eye (cornea or sclera) and enter the eye. These objects are usually travelling at high speed and are commonly made of metal. How do you get foreign bodies in the eye? Non perforating superficial foreign bodies are generally either blown or fall into the eye. This may occur, for instance, when working under a car or when outside on a windy day.  Penetrating eye injuries tend to occur when people are hammering or grinding. Under these circumstances small pieces of metal travelling at high speed hit the eye and enter it through the outer coat of the eye.  Is this a serious condition? Superficial foreign bodies are not usually a serious condition. Penetrating eye injuries on the other hand can be extremely serious and may lead to blindness if not detected and treated promptly. Even if treated appropriately, they may cause loss of vision.  What does a foreign body in the eye feel like? Superficial foreign bodies tend to be very uncomfortable. The foreign body may be stuck on to the cornea or the conjunctiva, causing a red, watery and gritty eye. The foreign material may have become stuck under the upper lid and this means that every time the eye opens and closes the pain increases.  Penetrating eye injuries, although they are much more serious injuries, paradoxically are often much less painful. The vision may be reduced but this is not always the case.  When should a doctor be consulted? It is advisable to consult a doctor if you think you have had a foreign body in your eye and it is continuing to cause irritation.  If you think something has gone into your eye while you have been grinding or hammering, even if you have little in the way of pain or loss of vision, it is essential that you consult a doctor immediately and tell them about the circumstances of your injury.  How does the doctor make a diagnosis? Superficial foreign bodies If you tell your doctor that you have felt something going into your eye then he or she will examine the eye, using a fluorescing stain as this helps to detect any foreign material on the surface of the eye. The eyelid needs to be turned outwards so that the underside of the lid can be examined and any foreign material removed from that surface. The material can be removed using a cotton bud, although occasionally a small needle may be required to lift any embedded particles from the eye. This is carried out with local anaesthetic drops and does not hurt.  Penetrating foreign material  If you tell your doctor that you have suffered a possible eye injury while carrying out a high risk activity such as hammering, then the eye will be examined in full detail. The vision will be assessed and it is possible that this may be reduced. There may be evidence that the pupil is distorted and there may be blood inside the eye. If the lens of the eye has been hit by the foreign material there may be evidence of an early cataract. X-rays or scans may be required if there is any suspicion that there is foreign material inside the eye. What happens if the foreign body is not removed from my eye? Superficial foreign material This will tend to cause persistent irritation and may lead to conjunctivitis. Sometimes the foreign material becomes buried and stops causing problems, although there may be some scarring.  Penetrating foreign bodies  The damage caused by an intraocular foreign body depends upon firstly the type of material that makes up the foreign body and secondly, the amount of damage that it causes as it passes into the eye.  Metal foreign bodies which have iron in them can cause a condition called 'siderosis' which gradually leads to poor vision over the following months to years. Some other metals and vegetable materials may cause rapid destruction of the eye or infection inside the eye. It is possible for a small foreign body to enter the eye and cause no apparent damage but it may lead to bleeding within the eye, early cataract formation, or damage to the retina. Surgery may be required to correct this damage. Surgery to remove penetrating foreign bodies  An operation is needed to remove foreign bodies that have penetrated inside the eye. This usually takes the form of a vitrectomy which involves going into the eye to remove the foreign material. At the same time any damage to the eye caused by the entry of the foreign material can be repaired. This may involve removal of haemorrhage, removal of the lens or repair of retinal damage. Will there be any long-term effects? Superficial foreign bodies are not sight threatening injuries and the eye tends to make a full recovery. Penetrating foreign bodies are potentially very serious and may lead to blindness or loss of the eye, even if treated appropriately.  How can foreign bodies in the eye being prevented?  Wear protective glasses or goggles when necessary, for example when welding, or using a grinder or sander, using a strimmer or doing DIY.