Written by: Julian Richardson, MD, MBA (NUEM PGY-2) Edited by: Andrew Moore, MD (NUEM ‘18) Expert commentary by: Brad Sobolewski, MD, MEd
A 40 yo construction worker comes to Emergency Department with a foreign body sensation in his left eye for two days. He states that he forgot to wear his eye protection while sanding a plank of wood the other day and felt like something has been scratching his eye ever since. Upon entering the room, his left eye is hyperemic and the patient appears to be in discomfort.
Approach to the painful red eye with foreign body sensation
The initial differential diagnosis to a painful red eye is broad and includes entities such as keratitis, corneal abrasions, corneal ulceration, acute angle glaucoma, iritis, chemical burn, scleritis, subconjunctival hemorrhage, and conjunctivitis. The patient’s history is particularly concerning for corneal abrasion, corneal ulceration, or globe rupture. A simple test to distinguish these diagnoses is the fluorescein exam.
Fluorescein exam
Fluorescein has been used in ophthalmology since the 1880s. This exam should be included for all patients where there is a suspicion of abrasion, foreign body, or infection. Fluorescein absorbs light in blue-wavelengths and emits energy in green wavelengths. It fluoresces in alkaline environments, for example Bowman’s membrane which is located below the corneal epithelium. It does not fluoresce in acidic environments such as the tear film over intact cornea. Because of this, defects in the cornea increase fluorescein uptake and assist in locating corneal damage.
The eye should first be numbed usually with the use of a topical anesthetic drop, such as tetracaine. Next, take a fluorescein strip and place one drop of saline or local anesthetic to the strip. Place this strip inside the lower lid, remove, and ask the patient to blink. The key to a good exam is to produce a thin layer covering the surface of the eye. If too much is applied, the excess can easily be removed by asking the patient to blot their eye while closed with a tissue. The eye should then be examined using a Wood’s lamp, blue filter of a slit lamp, or penlight with a blue filter
Warning! this dye will permanently stain soft contact lenses and clothing. Be sure to remove any contacts and have plenty of gauze or other absorbant material available prior to instillation. Irrigating the excess dye out the eye after examination will help minimize staining the patient’s clothing.
Corneal Abrasion
Definition
Scratch to the epithelium that comprises the cornea and exposes the basement membrane. Patients generally complain of a foreign body sensation, pain, photophobia, and some vision loss. On physical exam, the clinician may find injected conjunctiva, and decreased visual acuity (if the defect is large or lies in the visual axis).
Fluorescein Exam
Typically, abrasions are seen at the central part of the cornea due to limited protection of closure of the patient’s eyelids. The margins are sharp and linear in the first 24hrs. Circular defects suggests an embedded foreign body is present and may persist for greater than 48hrs. Foreign bodies can also produce vertical linear lesions and the upper lid should be lifter up to look for a foreign body under the eyelid
Management
Treatment with antibiotics have become the standard of care. Antibiotics are particularly indicated for abrasions caused by contacts (cover for pseudomonas), foreign bodies, or history of trauma with infectious or vegetative matter due to a higher risk of infection. Ophthalmic antibiotic therapy include: erythromycin ointment or sulfacetamide 10%, polymyxin/trimethoprim, ciprofloxacin, or ofloxacin drops (4 times a day for 3-5 days). Pain relief can be provided with oral or topical pain meds. Topical NSAIDs include .1% indomethacin, .03% flubiprofen, .5% ketorolac, 1% indomethacin, and .1% diclofenac. If symptoms persist greater than 24 hours after treatment the patient should follow-up with a physician. If the abrasion has not healed in 3-4 days the patient should be evaluated by an ophthalmologist.
Corneal Ulceration
Definition
When a defect in the corneal epithelium becomes infected with bacteria or fungi it is defined as a corneal ulceration. This is a common complication of corneal abrasions and if left untreated can result in a corneal perforation.
Fluorescein Exam
Corneal staining with infiltrate or opacification around the lesion should raise suspicion for ulceration. Contact lens wearers raise the suspicion of a Pseudomonal infection. Many Pseudomonal organisms fluoresce when exposed to UV light and fluoresce prior to fluorescein application.
Management
Concern for ulceration requires an urgent ophthalmology consultation within 24hrs. Discharged patients should be treated with antibiotic drops or ointment.
Globe Rupture
Definition
Full thickness injury to the cornea, sclera, or both secondary to penetrating of blunt trauma.
Fluorescein Exam
Seidel test: instill a large amount of fluorescein onto eye and looking for small stream of fluorescent blue or green fluid leaking from the globe.
Management
Once suspected, avoid further examination or manipulation, make the patient NPO, and place an emergent ophthalmology consultation. These patients also require broad spectrum IV antibiotic coverage with a 3rd generation cephalosporin or aminoglycoside and vancomycin to prevent post-traumatic endophthalmitis.
In summary, all patients with eye pain, particularly with a foreign body sensation, warrant a fluorescein exam. A wealth of information can be gained by this simple test and will guide the management of the patient.
Expert Commentary
This is a very comprehensive review of a common complaint in the Emergency Department. You correctly identified that one must be careful to avoid instilling too much fluorescein so as to cause a false positive result. Though a drop of tetracaine or saline dilutes the fluorescein from the strip somewhat the quantity is hard to control at times – especially in noncompliant patients (like the children I usually examine in the Pediatric Emergency Department). Excess fluorescein can collect across the eye making identification of small abrasions challenging. If you put too much in rinse the eye and try again. It is also incredibly important to not sent the patient home with tetracaine drops, as too frequent use may lead to further corneal injury. The evidence is based on animal models and case series and is far from complete. Read more on this great R.E.B.E.L. EM post (link: http://rebelem.com/topical-anesthetic-use-corneal-abrasions/).
One of the main pitfalls to the use of fluorescein strips is the risk of actually causing an abrasion. The method noted in this article – placing the strip inside the lower lid margin and asking the patient to blink – can cause an abrasion if the edge of the strip touches the cornea. This is particularly challenging to do in children, since even with proper restraint the blink reflex and their tendency to recoil is high. Therefore I recommend doing one of the following:
Hold the patient’s eyelids open. Drip the tetracaine or saline down the strip and allow it to drip into the eye, being careful to avoid touching the strip to the eye.
Make a fluorescein dropper. This is well detailed in the Tricks of the Trade: Fluorescein application techniques for the eye form Academic Life in Emergency Medicine (link: https://www.aliem.com/2015/06/tricks-of-the-trade-fluorescein-eye/). The Angiocath dropper allows for better control of droplet size and makes it easier to instill fluorescein into the squinting eye without the risk of touching the cornea.
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Brad Sobolewski, MD, MEd
Associate Professor, Assistant Director - Pediatric Residency Training Program
Division of Emergency Medicine
Cincinnati Children's Hospital Medical Center
How To Cite This Post
[Peer-Reviewed, Web Publication] Richardson J, Moore A. (2019, May 20). Corneal Abrasions [NUEM Blog. Expert Commentary by Sobolewski]. Retrieved from http://www.nuemblog.com/blog/corneal-abrasion
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References
Images courtesy of http://www.tedmontgomery.com/the_eye/
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Roberts, J. R., In Custalow, C. B., In Thomsen, T. W., & In Hedges, J. R. (2014). Roberts and Hedges' clinical procedures in emergency medicine. Ch 62. Opthalmologic procedures.
Gardiner, M. F. Overview of eye injuries in the emergency department. Retrieved September 16, 2017, from https://www.uptodate.com/contents/overview-of-eye-injuries-in-the-emergency-department.
Jacobs, D. S. Corneal abrasions and corneal foreign bodies: management. Retrieved September 16, 2017, from https://www.uptodate.com/contents/corneal-abrasions-and-corneal-foreign-bodies-management.
Waldman, N., Winrow, B., Denise, I., Gray, A., McMAster, S., Giddings, G., & Meanley, J. (2017). An observational study to determine whether routinely sending patients home with a 24-hour supply of topical tetracaine from the emergency department for simple corneal abrasion pain is potentially safe. Annals of Emergency Medicine, 02(016).
