Particulate matter or sand may be blown into the eye under windy conditions, but usually there is an appropriate history and the patient can date the exact moment that their eye became irritated.
Visual acuity is normal unless the foreign body is large and occupies the visual axis.
Treatment consists of removal of the foreign body and subsequent patching for the resultant corneal epithelial defect. Imbedded corneal foreign bodies rarely if ever can be flushed out and manual removal with a sharp or blunt instrument is often required. Large non metallic foreign bodies can be removed with any fine, preferably blunt, instrument, but metallic foreign bodies and their accompanying rust ring are best removed using a 25 gauge needle and slit lamp control. Topical anesthetic drops are an indispensable part of the diagnosis and foreign body removal and standard patching for 24 hours with a topical antibiotic ointment usually results in complete healing.