NOVEL TECHNIQUE FOR INTRAOCULAR FOREIGN BODY REMOVAL: Magnetized Disposable Microforceps. A Systematic Approach and First Clinical Result.

Purpose: To verify whether disposable microforceps can be magnetized to atraumatically attract and then grasp intraocular foreign bodies. An effective magnetization protocol was developed. The clinical relevance was tested, and a first practical application was performed.
Methods: The magnetic flux density (MFD) of a bar magnet and an electromagnet was measured. Steel screws were used to determine the magnetization protocol. Disposable microforceps was magnetized, MFD generated at the tip was measured, and the weight that can be lifted was tested. Foreign body removal with such forceps was performed.
Results: The electromagnet MFD was much higher than the bar magnet. The most effective magnetization protocol was to pass the screw from the end along the shaft and back over the electromagnet. Magnetized microforceps had a 7.12 mT change in MFD at the tip. Steel balls up to 87 mg could be lifted in buffered saline solution. In clinical use, the intraocular foreign body could be attracted and grasped safely.
Conclusion: Disposable microforceps can be easily and inexpensively magnetized. The achievable MFD is clinically relevant to attract typical intraocular foreign bodies. An electromagnet is best suited for this purpose. With such prepared forceps, foreign bodies can be attracted atraumatically and grasped securely.