Ophthalmology · Trauma

Corneal Abrasion

USMLE2PANCE
7

Bets

The facts most likely to be tested

1

The gold standard for diagnosis is fluorescein staining under cobalt blue light revealing a linear or punctate epithelial defect.

Confidence:
2

Patients typically present with severe eye pain, photophobia, foreign body sensation, and tearing following minor ocular trauma.

Confidence:
3

Topical anesthetic drops (e.g., proparacaine) provide immediate diagnostic confirmation by relieving pain, but they are strictly contraindicated for home use due to risk of corneal melting.

Confidence:
4

Contact lens wearers require pseudomonal coverage with topical fluoroquinolones (e.g., ciprofloxacin or ofloxacin) to prevent bacterial keratitis.

Confidence:
5

Patching is no longer recommended for routine abrasions as it does not improve healing time and may increase the risk of infection.

Confidence:
6

Seidel sign, defined as the streaming of aqueous humor away from a puncture site, indicates a globe perforation and necessitates an emergent ophthalmology consultation.

Confidence:
7

Management for non-contact lens wearers includes topical antibiotic ointment (e.g., erythromycin or polymyxin/bacitracin) and oral analgesics.

Confidence:

Vignette unlocked

A 24-year-old male presents to the urgent care clinic complaining of severe left eye pain and tearing that began after he poked his eye with a tree branch while hiking. On physical examination, the patient has significant photophobia and keeps his left eye closed. Visual acuity is 20/20 in both eyes. A fluorescein stain is applied, and examination with a cobalt blue light reveals a linear epithelial defect on the central cornea. The patient does not wear contact lenses.

What is the most appropriate management for this patient?

+Reveal answer

Topical antibiotic ointment (e.g., erythromycin) and oral analgesics.

The patient has a classic corneal abrasion confirmed by fluorescein staining; since he is not a contact lens wearer, standard treatment involves topical antibiotics to prevent infection and pain control, while avoiding eye patching.

Mo

Depth

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Etiology / Epidemiology

Common in contact lens wearers and trauma. Often caused by fingernails, foreign bodies, or makeup brushes.

Clinical Manifestations

Severe foreign body sensation, photophobia, and tearing. Fluorescein staining reveals linear epithelial defects.

Diagnosis

Fluorescein staining with cobalt blue light is the gold standard. Rule out intraocular foreign body.

Treatment

Topical antibiotics (erythromycin or polymyxin/trimethoprim). No topical anesthetics for home use.

Prognosis

Heals in 24-48 hours. Monitor for corneal ulcer or secondary infection.

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Epidemiology & Etiology

Most frequent ocular injury in primary care and ED settings. High-risk groups include contact lens wearers (risk of Pseudomonas) and those with occupational exposure to debris. Common mechanisms include accidental trauma, foreign bodies, or improper contact lens removal.

Pertinent Anatomy

The cornea is the most highly innervated tissue in the body, explaining the intense pain associated with epithelial disruption. The epithelium regenerates rapidly, while deeper stromal involvement leads to scarring.

Pathophysiology

Mechanical trauma strips the superficial corneal epithelium, exposing the underlying nociceptive nerve endings. This triggers a reflex arc causing blepharospasm, miosis, and lacrimation. If the basement membrane is breached, healing is delayed and risk of recurrent corneal erosion increases.

Clinical Manifestations

Patients present with acute onset of foreign body sensation, intense photophobia, and tearing. Examination reveals conjunctival injection and ciliary flush. Red flags include vision loss, hypopyon, or fixed pupil, which suggest corneal ulcer or globe rupture.

Diagnosis

Fluorescein staining viewed under cobalt blue light is the gold standard for visualization. The defect appears as a bright green area of uptake. Always perform a Seidel test if penetrating trauma is suspected to rule out aqueous humor leakage.

Treatment

First-line therapy is topical antibiotic ointment (e.g., erythromycin) to provide lubrication and prevent infection. Do not prescribe topical anesthetics as they cause corneal melting and delayed healing. Contact lens wearers require fluoroquinolones (e.g., ciprofloxacin) to cover Pseudomonas.

Prognosis

Uncomplicated abrasions typically heal within 24-48 hours. Corneal ulceration is the primary complication, especially in contact lens users. Patients should be instructed to avoid contact lenses until the eye is fully healed.

Differential Diagnosis

Corneal Ulcer: presence of white infiltrate/opacification

Foreign Body: visible object requiring removal

Herpetic Keratitis: dendritic pattern on staining

Uveitis: ciliary flush and cells/flare in anterior chamber

Chemical Burn: history of exposure, requires immediate irrigation