Cornea
Corneal Foreign Body / Rust Ring
Also known as: corneal foreign body, rust ring, metal foreign body, embedded corneal foreign body, subtarsal foreign body, welding foreign body, grinding foreign body, corneal FB
Filed as: Urgent
Source-cited from the record's own evidence list. Clinical content programme led by Dr Ankit Mathur, PhD, Grad Cert Ocu Thera, B.S. Optom. How the clinical content is governed
Clinical decision support only
Overview
A superficial corneal foreign body is common in optometry, but metal-on-metal and high-velocity mechanisms must be treated as a possible penetrating injury or intraocular foreign body from the outset. The workflow is VA first, mechanism, lid eversion, fluorescein/Seidel assessment when safe, superficial removal only when clearly safe and within competence, and urgent ophthalmology/ED for open-globe, IOFB, deep/central, infected, or uncertain cases.
Recognition
Symptoms: what patients report
- Foreign-body sensation, pain, tearing, photophobia, or blepharospasm.
- Redness and irritation after grinding, drilling, welding, gardening, wind exposure, or occupational debris.
- Blurred vision if the foreign body, rust ring, epithelial defect, or tear film disruption is central.
- Recurrent scratching sensation with blinking suggests subtarsal foreign body.
Signs: what the examination shows
- Visible corneal foreign body, rust ring, or residual epithelial defect.
- Fluorescein staining around the lesion or tracking scratches from a subtarsal foreign body.
- Conjunctival injection and tearing.
- Central, deep, multiple, organic, or contact-lens-associated lesions have higher risk.
- Seidel positivity, irregular/peaked pupil, hyphaema, AC depth asymmetry, or reduced vision suggests penetrating injury/open globe.
What OptoGuide™ covers for corneal foreign body / rust ring
- Pattern reasoning: what this combination of findings points to, and its differentiators
- Don't-miss risks and escalation triggers
- Management tiers with linked Australian therapeutics
- Referral urgency, specialty, and letter drafting
Sources
- Corneal (or other superficial ocular) foreign body — College of Optometrists CMG
- Anterior Eye Disease and Therapeutics A-Z (Bruce & Loughnan) — standard reference text
- Use of Topical Anesthetics in the Management of Patients With Simple Corneal Abrasions: Consensus Guidelines From the American College of Emergency Physicians. Green SM, Tomaszewski C, Valente JH, Lo B, Milne K. Annals o
- Infectious Keratitis in 2021. Durand ML, Barshak MB, Chodosh J. JAMA. 2021;326(13):1319-1320.
Standard texts: Kanski's Clinical Ophthalmology: A Systematic Approach, The Wills Eye Manual, Oxford Handbook of Ophthalmology, Oxford American Handbook of Ophthalmology, Signs in Ophthalmology: Causes & Differential Diagnosis.