Corneal iron debris cannot be removed cleanly, and another corneal foreign body removal may be considered after 2 to 3 days depending on corneal recovery and the development of the rust ring.
The cornea is a transparent transverse oval tissue structure located in the center of the front part of the eye, slightly convex forward. The thickness of the cornea is approximately 0.5 mm in the center and 1.0 mm in the periphery.
The histology is divided into five layers, with the outermost layer being the epithelial cell layer, which is thinner at approximately 35 micrometers thick. Generally, iron filings are closely connected to the epithelial cell layer, and foreign body removal will damage the corneal epithelium, which needs to be repaired after the growth of the corneal epithelium and then removed again.
The iron filings usually produce rust rings, which are located deep in the corneal epithelium and grow outward as the corneal epithelium grows. Two to three days after the removal of a foreign body, depending on the degree of corneal repair and the condition of the rust ring, another corneal foreign body removal operation can be performed.