Corneal Superficial Injury
Corneal superficial injury refers to minor, non-penetrating trauma affecting the corneal surface, most commonly corneal abrasion or corneal foreign body.
This updated UKMLA guide to corneal superficial injury is based on NICE CKS, which covers: causes, symptoms, assessment, referral, and management.
Terms and Definitions
Corneal abrasion: superficial epithelial defect
Corneal foreign body: material on or embedded in the corneal surface, often causing abrasion
Corneal laceration and intra-ocular foreign body are NOT superficial corneal injuries
- Corneal laceration: partial or full-thickness corneal defect
- Intra-ocular foreign body: foreign body has entered the eye
They involve deeper ocular trauma and may indicate an open-globe injury, which is an ophthalmic emergency.
Causes
- Mechanical trauma (e.g. fingernail, twig, paper edge, mascara brush, trichiasis)
- Foreign bodies (e.g. dust, glass, rust)
- Contact lens insertion or removal
- Injury upon removal is more common
- Areas of the corneal epithelium can become adherent to contact lenses and be removed with them if the lens and eye are dehydrated or the lens is ill-fitting
- Chemical, radiation, flash burns
Clinical Features
| History of precipitating event (often present) | Possible precipitating events include:
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| Clinical presentation | Typically unilateral:
Relatively minor superficial injuries can cause significant pain as the cornea is densely innervated with sensory fibres from the ophthalmic branch of the trigeminal nerve. |
| Signs of a corneal foreign body |
A metallic foreign body can give rust rings |
Complications
Serious complications resulting from corneal superficial injury are rare
- Corneal ulceration
- Infective keratitis
- Anterior uveitis
- Recurrent erosion syndrome (spontaneous abrasions can occur days to years after an initial abrasion heals)
Assessment and Management
Referral Criteria
Important features suggesting penetrating eye injury +/- open globe injury
- Dilated, nonreactive or irregular pupil
- Protruding iris
- A ruptured globe may present with blue, brown or black material on the surface of the eye (iris or choroid plugging the wound)
- Seidel sign on fluorescein staining: a dark, waterfall-like stream seen under cobalt blue light
- Caused by aqueous humour leaking through a corneal or scleral defect and diluting the fluorescein dye
- This indicates an active aqueous leak and suggests a penetrating/open-globe injury
Indications for immediate referral to emergency eye service:
- All high-velocity injuries (e.g. from drilling, lawn mowing, hammering)
- Injuries caused by sharp objects (e.g. glass, knives, pencils, thorns)
- Suspected penetrating eye injury
- Suspected intra-ocular foreign body
- Chemical eye injury – immediately irrigate the eye with copious irrigation fluid for 20-30 min, then refer to ophthalmology
- Foreign body that cannot be removed safely in primary care
- Organic material foreign body (e.g. seeds, soil, insect scales, caterpillar setae) due to a higher risk of infection and complications
- Foreign bodies in or near the cornea centre due to a higher risk of permanent visual loss
- Suspected infection or corneal ulcer
- Any of the following red flags
- Severe pain
- Irregular, dilated or non-reactive pupils
- Significant reduction in visual acuity
- Hypopyon (pus in the anterior chamber)
- Hyphema (blood in the anterior chamber)
- Large or deep abrasions
- Corneal opacity
Have a low threshold for referral of young children who may not be able to explain symptoms or are reluctant to open their eyes for examination
Discuss the following with ophthalmology or refer:
- Superficial corneal injury associated with contact lens use
- Presence of a rust ring
Primary Care Assessment and Management
Beyond a detailed history, assessment should include the following:
- Visual acuity with a Snellen chart
- Eye movements
- External eye examination, including the conjunctiva, cornea, eyelids, sclera and anterior chamber
- If a penetrating injury has been excluded, evert the upper eyelids to check for foreign bodies
- Fluorescein staining
- Examine under cobalt blue light using an ophthalmoscope or Wood’s lamp
- Corneal epithelial defects stain bright green (normal conjunctiva / cornea does not show focal bright-green staining)
- Some typical staining patterns
- Traumatic abrasions: linear or geographical shapes
- Foreign body under the upper lid (subtarsal): multiple vertical lines on the superior cornea
- Contact lens-related injury: several punctate lesions coalescing around a central defect
If the patient is experiencing significant pain, consider a topical anaesthetic to ease symptoms and aid examination.
Primary care management:
| If foreign body is present | Ensure to check visual acuity before, and after attempting removal
Methods of removal:
Foreign body under the upper lid (subtarsal) needs eyelid eversion to access it. Refer to ophthalmology if:
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| Symptom relief |
Do NOT offer:
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| Antibiotic therapy | Consider topical antibiotics (e.g. chloramphenicol ointment for at least 5 days) if there is a risk of infection
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| General management | Patient education:
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| Follow up | Arrange follow-up in 24 hours
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