Removal of Metallic Foreign Bodies with Complete Penetration of the Cornea: Introduction of a New Approach.

Purpose: The purpose of this study was to present a new ab interno approach and relevant case series using a polymer-tipped cannula for the removal of metallic foreign bodies that penetrate the full thickness of the cornea and are located in the posterior corneal region.

Methods: Corneal foreign bodies located on the posterior side of the cornea were gently pushed toward the epithelial side with a polymer-tipped cannula placed using a side-port incision, to be removed without damaging the corneal endothelial layer. The polymer-tipped cannula is specially angled to keep it at a distance from the corneal endothelial layer. In this way, unnecessary endothelial contact and the risk of possible endothelial loss are minimized. The foreign body was held by the epithelium with forceps and carefully removed along the corneal perforation line.

Results: This technique was performed in 5 eyes of 5 patients. The mean patient age at the time of surgery was 38.0 ± 12.1 years (range, 28-59 years). Anterior segment optical coherence tomography showed a metallic foreign body and its shadow that completely penetrated the cornea with the deterioration of the endothelial layer in all cases. In all cases, the corneal foreign body was successfully removed. While preoperative corneal endothelial cell density was 3040.0 ± 512.8 cells/mm2, postoperative corneal endothelial cell density was 2927.2 ± 608.1 cells/mm2 at the third postoperative month, and there was no significant corneal endothelial cell loss in any of the cases (P = 0.31).

Conclusions: The ab interno approach, performed with a polymer-tipped cannula for the removal of corneal foreign bodies that penetrate deeply, stands out as an important surgical method. This method offers a reliable and effective solution by preventing the foreign body from falling into the anterior chamber and minimizing endothelial damage.