8th December 2023

Corneal abrasion

Up to 24% of patients presenting to an emergency department with an eye issue have a corneal abrasion. In primary care, they account for 2% of all visits. Corneal abrasions are one of the commonest form of anterior segment trauma. A cornea is abraded when there is removal or loss of the epithelium, leading to a defect in the affected area. Common causes of corneal abrasion are fingernails (usually accidental injury from a child), contact lenses, cosmetic brushes, occupational exposure in high-risk occupations (e.g. mining, metal work, welding), sport-related trauma and abrasions from subtarsal foreign bodies. Corneal epithelial defects can also occur due to a breakdown of the epithelial cells from disease processes such as exposure, dry eye syndromes and neurotrophic keratopathy. In hospital, high-risk patients include NICU patients and ventilated adults. Patients present with redness, pain, foreign body sensation, photophobia, watering and blurred vision. A careful history to identify, if possible, the cause of trauma is necessary. Injury from organic matter carries a higher risk of contamination and, in particular, fungal inoculation. The cornea should be stained with fluorescein to delineate the defect. A seidel test (observation of washing out of fluorescein from the cornea surface by aqueous fluid from the anterior chamber) should be performed to assess for any signs of leakage indicating penetrating eye injury. An abnormal pupil shape might be a sign of penetrating eye injury. Eyes with abrasion secondary to blunt trauma or evidence of trauma in other ocular tissues will require ophthalmological assessment. Eyes with hyphaemas or hypopyon also necessitate urgent ophthalmology referral.

Image Source: Wikimedia Commons (2017). Corneal Abrasion with Fluorescein Staining, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Corneal_Abrasion_with_Fluorescein_Staining.jpg (Accessed on: 5  May 2022).

Small epithelial defects heal quickly, and the principle of treatment is to prevent infection during this healing process. Topical antibacterials such as chloramphenicol are usually sufficient. In patients with suspected exposure to fungal matter, appropriate prophylaxis might be necessary. Oral analgesia can be used for simple pain relief. Contact lens users should discontinue contact lens use during treatment. Larger defects and deeper defects take longer to heal and can be complicated by infection. Corneal abrasions increase the risk of developing recurrent corneal erosions where there is spontaneous breakdown of the epithelium. This is because of a dysfunctional adherence of the epithelial cells post-trauma. Persistent epithelial defects or recurrent corneal erosions will need specialist treatment such as tarsorrhaphy, amniotic membrane graft, micro-puncture, etc.