Foreign body removal in community practice

The question:

An otherwise healthy mechanic in his 30s presents in practice with soreness in one eye. He explains that the soreness appeared after he cut a rusty exhaust off a car two days ago. How would you diagnose in this case, and what would your management be?
 

OT’s panel says...

Kevin Wallace: The obvious culprit in a case like this is metallic foreign body. These can be uncomfortable but are usually easy to find and not too difficult to remove. I’d first want to know what he was doing – particularly as the speed of impact of a foreign body is very important. If he was grinding and a fragment got into the eye this can cause a lot of damage, but if it was debris just falling into the eye that is less worrying. If there is any suspicion of corneal penetration, you should not attempt to remove a foreign body and should seek advice from your local eye casualty.

The main investigation will be examination of the eye with a slit lamp, using fluorescein to look for foreign body tracks – if a foreign body is trapped under the eyelid, it leaves a characteristic pattern of stain. Instillation of a topical anaesthetic will aid in examination, as these patients can be quite uncomfortable, and that will make removal much easier too. It is definitely useful to evert the eyelids, even if you think you have found the cause – I recently saw a patient with a simple corneal foreign body but after I had removed it I found another particle under the upper lid.

If I do find a foreign body my basic rule is to start with the least sharp instrument possible and escalate as required. I’m not a fan of cotton buds as they can leave fluffy debris, but have purchased foam spears, which are very useful – they’re stiff enough to pick up many foreign bodies but still soft enough not to do much damage.

If the foreign body is embedded in the cornea it may need to be picked off with a needle, if you are comfortable to do that. The most important point here is to hold the needle tangential to the cornea to reduce the risk of damage. I find it very helpful to use a cotton bud in the handle end of the needle – that makes it much easier to control it, in the same way as a screwdriver in the palm of your hand is more stable than one just in your fingertips.

If the foreign body is metallic then there may be a rust ring. This can be removed either carefully with a needle or with an Alger brush.

For a small foreign body no other treatment may be required following removal, but for something with a higher risk of infection I usually prescribe a few days of chloramphenicol ointment (which in cases like this could be sold or supplied by any optometrist). I always warn patients that it’s the anaesthetic making them feel much better just now. Once that wears off, I expect their eye to be uncomfortable again – but the ointment will help and usually they will feel much better the next day.

The main investigation will be examination of the eye with a slit lamp, using fluorescein to look for foreign body tracks

Ceri Smith-Jaynes: I do like the heroism of a foreign body removal. That’s a great tip, Kevin, about using the cotton bud to create a handle for the needle; I’ll be trying that out. I like to slightly bend the very tip of the needle, so it’s a bit less pointy.

I’d just like to add to check visual acuity before and after, and to examine the anterior chamber for activity. We have an Optomap, so I’ll usually take a widefield fundus image to make sure there’s no penetrating foreign body; if in doubt, dilate and use the Volk. The Seidel test is useful to check for a leaking wound – you’ll need a bit more fluorescein in than when you check for staining.

If there’s a significant corneal epithelial defect, I’ll often get the patient to use chloramphenicol ointment until it’s healed and then a thick lubricant before bed for a month or so, to help prevent a recurrent corneal erosion. The healed epithelium can be a bit weak, and I don’t want the closed lid sticking and opening the wound back up when the patient wakes up.

It’s worth finding out which optometrists in your area are competent in foreign body removal. If you have a CUES or MECS scheme, you could refer to another optometrist rather than having the patient wait in A&E or a walk-in centre.

After removing a bit of metal from his cornea, I was preaching to the last patient about safety eyewear when he gave me an ironic smile; he was a lecturer in health and safety and had given out the same speech many times himself.

Ankur Trivedi: A slightly curved needle is advantageous as it makes the tangential approach easier. Aside from that, I think all other points that I would make have already been covered in the advice given by Kevin and Ceri.