- Ocular foreign bodies can lead to loss of vision and so, if they are suspected, they should be treated quickly.
- A foreign body may be found
- on the conjunctiva (it is important to invert the eye lid to inspect for such FBs),
- in the cornea (usually fine, sharp particles e.g. glass/metal etc) or
- intraocular (usually high velocity metal particles e.g. metal on metal strikes).
- There may be a history of known foreign body in the eye or injury suggestive of occular foreign body (e.g. dust flown into eye or working in a wood/metal workshop)
- The patient may complain of irritation, pain, FB sensation, tearing and/or red eye (injection) if the FB is on the conjunctiva.
- If the FB is on/in the cornea, the patient will usually complain of intense ocular pain with some photophobia (as well as symptoms of conjunctival FB).
- Intraocular FBs typically do NOT cause any pain, but they can cause damage to the lens and/or retina so may cause some visual disturbance (usually, however, these patients are asymptomatic).
- On examination
- A full examination of the conjunctiva (including under the eyelid) should be done in search of any FB that may be able to be removed there and then. There is usually scleral injection around the site of the FB.
- Corneal FBs are more easily seen under slit lamp examination. There may be normal or reduced visual acuity (due to corneal oedema- or chemosis); there is usually some ciliary injection; an entry site may be visualised using fluorescein and there may be some hypopyon (evidence of immune response to FB).
- An entry point may be seen using fluorescein but this might have healed depending on the time to presentation.
- A FB can usually be removed there and then with saline irrigation
- If this is unsuccessful, try using a wetted cotton tip (NB this MUST be done carefully and correctly to avoid further damaging the eye or causing secondary infection).
- Anaesthetic (lidocaine) drops may be required, particularly for corneal FBs/
- If this is unsuccessful, occasionally a hyperdermic needle can be used, although extreme care is required (e.g. approach tangentially)
- In intraocular FB needs to be identified, so normally the eyes are X-rayed to do this. Removal of the Fb depends on the location:
- An anterior chamber FB can be removed by paracentesis (drainage)
- An intralenticular FB, unless it causes a cataract, can often be left in situ
- A vitreous chamber FB usually requires a vitrectomy
- In most cases, chloramphenicol is also usually given to prevent secondary infection and to help soothe the eye.
Further management of secondary eye injury/damage may or may not be required. See also, corneal abrasions.