Procedure: Ocular foreign body removal

The Procedure

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Ocular foreign body removal

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Instructions

Indications

• Suspected conjunctival or corneal foreign body

Suggested by:

• Mechanism
• Foreign body sensation
• Eye pain
• Photophobia

Contraindications (absolute in bold)

• Penetrating eye injury (requires IV Abx and ophthalmology assessment)
• Noncompliant patient (e.g. children require specialist review with anaesthesia)
• Foreign body over pupil (consider referral to ophthalmology if available)

The factors suggesting penetrating eye injury are:

• High risk mechanism (working with wire, power tool, hammering, lack of eye protection)
• Decreased in visual acuity (compared to normal or uninjured eye)
• Eccentric or teardrop pupil
• Hyphaema
• Tenting or chemosis of the cornea or sclera at the site of globe puncture
• External prolapse of internal structures (iris, ciliary body, or choroid)
• Positive Seidel sign (clearing of instilled fluorescein in a teardrop pattern away from the puncture site)

Alternatives

• Irrigation with 0.9% Sodium Chloride
• Referral to ophthalmology

Informed consent

• Verbal consent
• Less complex non-emergency procedures with low risks of complications

Potential complications

• Pain
• Failure (to remove foreign body)
• Penetrating eye injury (caused by needle)
• Infection (conjunctivitis, endophthalmitis)
• Scarring with visual compromise (if centrally located)

Procedural hygiene

• Standard precautions
• PPE: non-sterile gloves

Area

• Eye room with slit lamp

Staff

• Proceduralist

Equipment

• Sterile cotton bud
• Slit lamp with (cobalt) blue filter
• Bevelled needle (23G – 25G)
• Small syringe
• Rotary ophthalmic corneal burrs (used as an alternative to using a needle or for rust ring removal)

Positioning

• Patient sitting comfortably at slit lamp
• Chin on chin rest, forehead firmly against head rest (reducing movement)

Medication

• Local anaesthetic drops (improve comfort aiding examination)
  • Amethocaine (tetracaine) 0.5%, Oxybuprocaine 0.4%, Benoxinate 0.4%, Lignocaine 1%
• Fluorescein (visualise abrasions under blue light after foreign body removal)
  • Fluorescein 1-2% drops or Fluorescein paper
• Antibiotics (infection prevention, ointment preferred for lubricant and protective function)
  • Chloramphenicol ointment or drops 0.5% 4 times a day for 3 days or
  • Ofloxacin 0.3% 4 times a day for 3 days (for contact lens wearers or organic foreign body – pseudomonas)

Sequence (visual acuity)

• Anaesthetise eye with 1 to 2 drops of topical anaesthetic
• Measure visual acuity in each eye using a Snellen chart (keeping glasses on if required)
• Measure best corrected acuity with a pinhole (if vision is not optimal)
• If vision improves with a pinhole this is reassuring  (the patient requires a sight test or prescription change)

Sequence (slit lamp preparation)

• Sit patient with their chin on the rest and forehead against the strap
• Align patient eye level with the black line on the slit lamp
• Set the light filter to produce bright white light
• Increase light beam height by rotating the top dial on the illumination tower (balance illumination and comfort)
• Note that turning this dial fully until it clicks produces blue light used for fluoresceine exam
• This blue light different to setting the filter to produce a green “red free” light (used for blood vessels and bleeds)
• Set the width to 1 mm or 10 on the scale on the bottom dial on the moving arm
• Set the swing arm at 45 degrees to the patient’s eye (reducing reflection and improving depth assessment)

Sequence (examination for foreign body and excluding a penetrating injury)

• Examine the unaffected eye without fluorescein
• Examine the affected eye without fluorescein
• Evert affected eye lids then examine conjunctiva
• Note the position and size of any foreign bodies
• Examine for signs of penetrating eye in injury without fluorescein (if signs present refer to ophthalmology)

Sequence (removing sub-tarsal foreign bodies)

• Using a cotton bud evert the lower and upper lids
• If a foreign body is located ask patient to fix vision in a position which allows best access
• Remove using a cotton bud with a rolling motion lifting the superficial foreign body from the surface

Sequence (needle removal of embedded foreign bodies)

• Explain the needle is held parallel to the eye and does not enter the eye
• Explain you will hold needle tip to scoop off the foreign body
• Perform the procedure using the ipsilateral hand to the patient’s eye
• Hold the 23 – 30 G needle as you would hold a pencil
• Position your operating hand (ulnar) against the patient’s face (zygomatic arch) or slit lamp frame
• Use the middle and fourth finger to fix lid position and keep the lids open
• Approach the foreign body from the periphery of the cornea without magnification until within 1 cm
• Initially look over the top of the lenses of the slit lamp until you see the needle come into the light beam
• Then look through the lens and use magnification to guide the needle the final 1 cm onto the corneal surface
• Pick up or scoop the foreign object away from the cornea
• Repeat as required to fully remove the foreign body
• The needle can be bent (with sterile haemostat) or attached to a small syringe to improve angle and control
• If the foreign body become dislodged but remains on the surface of the eye use irrigate or a cotton bud
• Reassess upper and lower lids with eversion to confirm foreign body removed

Sequence (burr removal of embedded foreign bodies)

• Explain the burr is a blunt instrument and cannot enter the eye
• Explain you will hold burr tip parallel to the eye to flick off the foreign body
• Hold and approach with the burr as you would for a needle
• Gently and briefly press the rotating burr against the foreign body
• Retreat and assess how much was removed
• Repeat as required to fully remove the foreign body

Sequence (fluorescein examination after removal of foreign body)

• Once removal attempted apply fluorescein to the affected eye
• Rotate the top dial on swing arm fully to switch to cobalt blue light
• Estimate the size and position of the epithelial defect
• Assess for corneal leak (seidels sign) with immediate ophthalmology follow up if found (penetrating injury)
• If there is a corneal defect without a foreign body consider corneal abrasion or infection

Post procedure care

Documentation

• Document approximate size and position of epithelial defect (e.g. 2 mm defect at 6 O’clock position outside pupil)
• Document type of foreign body if known (metal, vegetation)
• Document method of removal, difficulties and if any material remaining

Discharge medications:

• Chloramphenicol drops 0.5% 4 times a day for 5 days or
• Ofloxacin 0.3% 4 times a day for 3 days (for contact lens wearers or organic foreign body – pseudomonas)
• Oral pain relief (paracetamol, ibuprofen, oxycodone if large epithelial defect)

Discharge instructions

• Keep eye clean and avoid swimming for a week
• No contact lenses wear for a week (risk of pseudomonas keratitis)
• Return for reassessment if increase in pain, irritation, redness, or a decrease in vision (Keratitis)

Ophthalmology follow up within 24 hours is recommended for patient at high risk of complications:

• Corneal defects over pupil or greater than 5 mm (greater risk of complications)
• Retained foreign body or rust ring
• Organic material or contact lens wearers (risk of bacterial keratitis)
• Purulent discharge (infection present)

Other patients should return to the emergency department if symptoms worsen or are not resolved at 48 hrs

• To confirm epithelium healing (refer to ophthalmology if incomplete healing)
• To exclude keratitis (refer to ophthalmology if increase in pain, irritation, redness, or a decrease in vision)

Tips

• Suspected penetrating injury = systemic antibiotics + eye shield + immediate ophthalmologic consultation
• Proceed from least invasive to more invasive; non-metallic foreign bodies can often be rinsed away with irrigation
• Vertical linear abrasions on cornea are suggestive of a sub-tarsal foreign body
• Risk of corneal perforation by a needle is low if the approach is tangential and your hand is anchored to the face
• Remove foreign bodies prior to impairing view with fluorescein application

Discussion

Fluorescein emits green wavelengths when exposed to corneal basement membranes (alkaline) under blue light. To see this reaction shine “cobalt” blue light on the cornea by rotating the top dial on the illumination tower until it clicks. This is different to setting the light filter to produce green or “red-free” light (a common error). The green light is used by specialists to highlight blood vessels and vitreous haemorrhage, and although it fluoresces bright yellow over epithelial defects, it has the potential to confuse the non-expert.

A rust ring may form around foreign bodies containing iron, typically those that are metallic. Rust ring formation takes a few hours. Debridement of rust rings is recommended and may be attempted in the ED on the first visit or at follow up. Removal is simplest after 24-48 hours when the ring often comes out as one lump. Central rust rings should undergo aggressive removal as they have the most impact on future vision. Small, retained rust may resorb without complication but follow up is recommended to ensure epithelial healing and avoid secondary iritis.

Rotary ophthalmic corneal burrs (also referred to as a spud, or “Alger brush”) are rotating tools without a sharp point and are a safe alternative for removing foreign bodies and rust. As the burr rotates it can flick out a foreign body. More commonly, it is used to shave down the rust ring from a metallic foreign body. Burrs create a larger epithelial defect than a needle. For this reason we prefer a needle but acknowledge the burr as an alternative for providers who prefer to use it. 

We believe discharge with topical anaesthesia with 1.5 ml of local applied 30 minutely for a maximum of 24 hours is most likely safe (practised by some departments) and supported by the best available evidence (1 RCT, and a large observational study). Previous studies raised concern over the possibility of delayed healing or overuse masking symptoms of worsening infection. Concerns remain in the ophthalmology community and more evidence will likely be required to make this mainstream practise. Additionally, some experts feel the benefit is minimal for small abrasions which typically heal overnight with pain greatly reduced after foreign body removal, antibiotic ointment, and oral pain meds.

We do not recommend cycloplegic drops (e.g. homatropine 2% BD) for corneal defects. They may have a small impact at reducing pain for large abrasions by inhibiting the pupil-constricting response to light which causes ache and photophobia. However they also last at least 24 hours causing glare, blocking accommodation interfering with near work such as reading.

We do not recommend eye patches. Simple fabric patches do not impair lid opening and may worsen abrasions. Pressure eye patches prevent lid opening and may reduce pain but are difficult to apply, impair assessment and application of antibiotics.  

Antibiotics are recommended for all patients due to a small risk of infective keratitis. Keratitis presents with an increase in eye pain, eye irritation, eye redness, or a decrease in their visual acuity. Many abrasions heal overnight. Patients with contact lenses or organic foreign material in the eye are at high risk of pseudomonas infection and a fluroquinolone (e.g. ciprofloxacin, ofloxacin) is recommended. We suggest low risk abrasions with resolution of symptoms within 48 hours do not need follow up, while those at higher risk of infection are followed up by ophthalmology within 24 hours.

References

• Sehu W. Emergency eye manual. 2nd edition. North Sydney: NSW Department of Health, 2009.
• South-Eastern Melbourne PHN Foreign Body in Eye pathway. South-East Melbourne Public Health Network. 2020. Available from: https://irp.cdn-website.com/b60ea18f/files/uploaded/pathways-ophthalmology-foreign-body-eye.pdf
• Fraenkel A, Lawrence RE, Lee GA. Managing corneal foreign bodies in office-based general practice. AFP Volume 46, Issue 3, March 2017. Available from: https://www.racgp.org.au/afp/2017/march/managing-corneal-foreign-bodies-in-office-based-ge
• College of Optometrists, UK. Corneal (or other superficial ocular) foreign body. Version 15 2020. Available from: https://www.college-optometrists.org/clinical-guidance/clinical-management-guidelines/corneal_orothersuperficialocular_foreignbody
• College of Optometrists, UK. Corneal abrasion. Version 15 2020. Available from: https://www.college-optometrists.org/clinical-guidance/clinical-management-guidelines/cornealabrasion
• Flanagan D. Common Eye Condition Management. Moorfield Eye Hospital, UK. Available from: https://www.moorfields.nhs.uk/sites/default/files/GP%20Handbook%20-%20Common%20eye%20condition%20management.pdf
• The Royal Victorian Eye and Ear Hospital. Clinical Practise Guideline: Emergency Department – Corneal Foreign Body 2020. Available from: https://eyeandear.org.au/wp-content/uploads/2021/08/Corneal-Foreign-Body-Clinical-Practice-Guideline.pdf
• Roberts JR, Custalow CB, Thomsen TW. Roberts and Hedges’ clinical procedures in emergency medicine and acute care. 7th ed. Philadelphia, PA: Elsevier; 2019.
• Jacobs DS. Corneal abrasions and corneal foreign bodies: Management. UpToDate 2021 Aug. Available from: https://www.uptodate.com.acs.hcn.com.au/contents/corneal-abrasions-and-corneal-foreign-bodies-management.
• Gardiner MF. Approach to eye injuries in the emergency department. In: UpToDate. Waltham (MA): UpToDate. 2020 Jan 14. Available from: https://www.uptodate.com/contents/approach-to-eye-injuries-in-the-emergency-department
• Brady CJ. How to Remove a Foreign Body from the Eye, 2020 May. MSD Manual. Available from: https://www.msdmanuals.com/en-au/professional/eye-disorders/how-to-do-eye-procedures/how-to-remove-a-foreign-body-from-the-eye
• Nickson C. Something in my eye, Doc. LITFL
• Camodeca AJ, Anderson EP. Corneal Foreign Body. Updated 2021 Apr 26. StatPearls Publishing; 2022 Jan.
• Brissette A, Mednick Z, Baxter S. Evaluating the need for close follow-up after removal of a noncomplicated corneal foreign body. Cornea. 2014 Nov;33(11):1193-6.
• Shaikh MH, Adams AD. Red-free versus cobalt blue illumination in fluorescein diagnostic staining of the external ocular surface. Hong Kong Journal of Ophthalmology. December 2003. Vol. 7 No. 1.
• Lim CH, Turner A, Lim BX. Patching for corneal abrasion. Cochrane Database Syst Rev. 2016 Jul 26;7(7):CD004764
• Meek R, Sullivan A, Favilla M, Larmour I, Guastalegname S. Is homatropine 5% effective in reducing pain associated with corneal abrasion when compared with placebo? A randomized controlled trial. Emerg Med Australas. 2010 Dec;22(6):507-13.
• Waldman N, Densie IK, Herbison P. Topical tetracaine used for 24 hours is safe and rated highly effective by patients for the treatment of pain caused by corneal abrasions: a double-blind, randomized clinical trial. Acad Emerg Med. 2014 Apr;21(4):374-82.
• Brilakis HS, Deutsch TA. Topical tetracaine with bandage soft contact lens pain control after photorefractive keratectomy. J Refract Surg. 2000 Jul-Aug;16(4):444-7. 
• Ball IM, Seabrook J, Desai N, Allen L, Anderson S. Dilute proparacaine for the management of acute corneal injuries in the emergency department. CJEM. 2010 Sep;12(5):389-96.
• Brissette A, Mednick Z, Baxter S. Evaluating the need for close follow-up after removal of a noncomplicated corneal foreign body. Cornea. 2014 Nov;33(11):1193-6.

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