From the Research
A retained rust ring after removal of a metallic corneal foreign body is significant because it can cause persistent inflammation, delayed healing, and potential scarring if not properly addressed. The rust (iron oxide) should be removed completely, typically within 24-48 hours of the initial injury. Treatment involves careful removal of the rust ring using a small-gauge needle, an ophthalmic burr, or an Alger brush under slit lamp magnification after applying topical anesthesia (such as proparacaine 0.5%) 1. Following removal, patients typically require antibiotic drops like moxifloxacin or ofloxacin 4 times daily for 5-7 days to prevent infection. A cycloplegic agent such as cyclopentolate 1% may be prescribed to reduce pain and ciliary spasm. Patients should be advised to avoid eye rubbing, swimming, and contact lens wear until healing is complete. Rust rings are problematic because iron can catalyze free radical formation, causing cellular damage and inflammation in the corneal tissue. Complete removal is essential as retained iron can lead to persistent epithelial defects, corneal opacification, and potentially permanent visual impairment if left untreated.
Key Considerations
- The use of a burr for rust ring removal was associated with a longer healing time in a study published in 2023 1.
- Antibiotic and antiseptic treatments were found to be equally effective in preventing infectious keratitis after corneal foreign body removal 1.
- The management of corneal foreign bodies should include accurate history, thorough examination, atraumatic removal, elimination of the rust ring, and appropriate antibiotic prophylaxis 2.
Treatment Approach
- Remove the rust ring completely within 24-48 hours of the initial injury.
- Use a small-gauge needle, an ophthalmic burr, or an Alger brush under slit lamp magnification after applying topical anesthesia.
- Prescribe antibiotic drops like moxifloxacin or ofloxacin 4 times daily for 5-7 days to prevent infection.
- Consider a cycloplegic agent such as cyclopentolate 1% to reduce pain and ciliary spasm.
- Advise patients to avoid eye rubbing, swimming, and contact lens wear until healing is complete.