Corneal Foreign Bodies and Rust Rings

Patients will not always recall a foreign body having entered the eye so it is important to have a high index of suspicion and examine for a conjunctival or corneal foreign body if a patient presents with an uncomfortable red eye.

Use of anaesthetic

Local anaesthetic may be needed both to examine the eye and to remove any foreign body – proxymetacaine has been shown to be the optimal agent [14].

Visualising the foreign body

The foreign body can usually be easily visualised although clues as to its position may be gained by the pooling of administered fluorescein around the foreign body and/or the presence of conjunctival injection adjacent to it.

Eyelid eversion

If there is a history of a possible foreign body entering the eye and it cannot be seen, then the eyelid must be everted to exclude a subtarsal foreign body, provided a penetrating injury is not suspected. If a subtarsal foreign body is present, it is easily removed using a cotton bud.

High-velocity foreign bodies

Also, where the history is of a high-velocity foreign body (e.g. metallic fragment from angle grinding or hammering a metal chisel), the possibility of a penetrating injury with an intraocular foreign body must be considered. For more information on this topic please refer to the reference session on Penetrating Trauma to the Eye.