60.9 Foreign bodies in the eye

Foreign bodies are often missed, because nobody looks for them. They can be embedded in a patient’s cornea, or lodged in his upper conjunctival fornix, so that they can only be seen when his eye is everted. Always instil some anaesthetic drops into his eye before you try to remove them. The risk with any foreign body is that the eye will become infected.

Figure 60.8: FOREIGN BODIES. A, common sites for foreign bodies. (1) The conjunctival fornix. (2) The cornea. Foreign bodies here usually lie within the fissure formed by the lids. (3) The anterior chamber. (4) The retina. B, single eversion of the lid. C, and D, double eversion. After Peyman, with kind permission.

Fortunately, most foreign bodies don’t go deeper than the conjunctiva or sclera. The commonest one to go right inside the eye is a piece of steel that breaks off a cold chisel when the patient hammers it. When this happens, he may have a stained area in his cornea, a tiny hole in his iris, and signs of an early cataract. He may also have been misdiagnosed as conjunctivitis. His history, and the fact that his eye remains red and watery should however make you suspicious. If a patient has a painful eye and he has been doing anything which might have caused a foreign body to enter it, assume that he has a foreign body in his eye until you have proved that he has not.