• Visual acuity of both eyes
• Intraocular pressure
• Pupils > size and shape, any pupillary defects

• When the event occurred
  • Sometimes patients present several days after the event occurred (e.g. pain from a flash burn that never relieved).
  • A foreign body that has been present for a long duration can result in white cell recruitment, a rust ring and infective keratitis.
• It is important to know what material you are looking for in the eye.
  • E.g. hammer to cement or grinding metal.
  • This is important so as to understand the velocity at which the object hit the cornea.
• Ask the patient whether they were wearing eye protection (this is also important for educating the patient about the importance of eye protection).

• Topical anaesthetic is the first step to deal with the pain prior to examining.
  • Children may need systemic ibuprofen.
• Then position the patient on the slit lamp once the pain is well managed.

• Observe the ophthalmology or Emergency registrar/consultant before starting to use the slit lamp.
• Ensure the eye pieces are dialled to zero, not a myopic refraction.
• Modify the position by moving the two eye pieces together to suit your interpupillary distance (so as to obtain one image instead of two).
• Switch the slit lamp on, turn on the white light and change it to 45 degrees from the direction you are looking at the patient.
• With this slit of light, you can work out where the foreign body is in the cornea.
• When prepared, ask the patient to put their chin on the chin rest and ensure their lateral canthus is aligned to the black line, and by this you will be able to observe their eye with the light.
• Also ensure their forehead is sitting on the forehead rest, and that their head is pushed forward.
• Focus the beam of light by looking at it on the patient’s nasal bridge, and then move to looking through it in the eye piece.
• By pushing the handpiece forward you are looking at deeper intraocular structures, e.g. the cornea, then the iris, and then the lens.
• Then ask the patient to look at your ear. If looking at the right eye ask them to look at your right ear.
• You may need to lift the upper lid with a cotton tip to get a good view of the cornea.

• Any issues with vision or intraocular pressures. The intraocular pressures are normally between 10-24, so if 5 or 30, this is alerting to something more serious.
• Comment on the pupil, if there are any irregularities in shape. E.g. peaking would indicate a perforation.
• Check the anterior chamber to ensure it is not flat and that it looks formed also commenting on any haemorrhages which can occur with blunt trauma.
• Another red flag would be no relief to topical anaesthetic.

• First, wet a cotton tip and brush gently on the foreign body, you may need to hold the upper eyelid up with your finger or another cotton tip.
• If this does not work, you can use the end of a needle bevel, either as a straight tip or bend in an ice-cream cone shape, and then brush gently down on the foreign body to see if you can dislodge it.
• Always look for more corneal foreign bodies, there may be some in the cornea, or the fornices.
• Even trained ophthalmologists sometimes have difficulty with removing corneal foreign bodies, if it’s a peripheral foreign body you can have an attempt, if it is central it is best for an eye specialist or remove it.

• Topical anaesthesia assists with the pain. Little children may need more assistance to gain cooperation, may need parental help.
• With adults, you can give them something to look at, e.g. a poster on the wall.

• This would result in a corneal reaction and possibly a bacterial infection.
• A rust ring can also develop around the central object causing scarring, this can be vision threatening.

• Removing the corneal foreign body is the main aim.
• If there is a residual rust ring, it is okay to leave this and apply chlorsig ointment, and follow up with an ophthalmologist.
• It is important to tell them that the pain will be there the same day of the removal. But if the pain continues the next day and is just as intense, the patient needs to return to the emergency department.

• Ensure they’re seidel negative, a test with 2% fluorescein to ensure no leak of aqueous solution. The fluorescein will turn the cornea yellow, and, if corneal perforation exists, you would see a waterfall effect which would be washing the fluorescein away.
• This is an urgent eye review.
• Dependent on the mechanism of injury you may need to do further investigations.
  • E.g. facial X-ray.

• The corneal foreign body may be deep, and when removed may reveal a full thickness injury.
• Digging too deep with removal may cause an iatrogenic laceration to the eyelid, or to the nose or eye when holding a needle under a microscope. This is a difficult skill to pick up.
• Always ask for supervision from seniors if you are not comfortable.

• Talk through this with a senior colleague. The most important factors are:
  • If the corneal foreign body is central.
  • If residual rust ring needs to be removed by eye registrar.
  • If it is difficult to remove.
  • If the patient only has one eye.
  • If the vision is not what you expected, or out of the normal range.

• Give the patient analgesia, e.g. NSAIDs.
• Antibacterial drops or ointment
  • Fill the eye with this and double pad shut (fold one against the lid and then another one).
  • The corneal epithelium heals more quickly when it is closed.
• Arrange follow up with an ophthalmologist or optometrist.
• Ensure the patient that the pain will get better and if it doesn’t, to represent to the emergency department.

• No, the use of anaesthetic drops impairs the healing of the corneal epithelium, so they should never be prescribed on discharge.
• Anaesthetic drops would also mask the pain which would bring them back to the emergency department if something’s not right.
  • E.g. the presence of another corneal foreign body, or a more penetrating eye injury.

• Ensure the patient the pain will persist for the rest of the day, and it won’t be completely gone the next day, but should be improving by the next day.
• Additionally, the vision won’t be perfect on day one, but should get better slowly; it takes longer to improve.
• If the next day the pain is worse or the vision is worse, they need to represent to the emergency department.

• The Eye emergency manual – provides simple ways of working out what’s wrong with the patient.

• Ask for help if feeling out of your depth.
• If an eye registrar comes to examine the patient, watch and learn, ask questions, especially with the slit lamp.
• Always arrange follow up with either the optometrist or ophthalmologist.
• Remind the patient of the ‘red flags’ for representation.

Eye Emergency Manual – An Illustrated Guide. Agency for Clinical Innovation (2nd edition) – https://www.aci.health.nsw.gov.au/__data/assets/pdf_file/0013/155011/eye_manual.pdf