The Use of a Magnet to Remove Corneal Foreign Bodies
Phase: NA
Conditions: Corneal Foreign Body
Sponsor: Kendall Healthcare Group, Ltd.

Removing a Corneal Foreign Body with a Magnet 
NCT03778190 
Nov 15, 2018 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Introduction 
 
The removal of corneal foreign bodies is a common ophthalmologic procedure in the emergency 
department (ED) [1].   There are a few different techniques for removing corneal foreign bodies 
[2]. A cotton-tipped applicator is useful for superficial foreign bodies that can be swept away, 
but this does not work for adherent foreign bodies.  For adherent corneal foreign bodies, the most 
common technique in the ED is to use a needle to dislodge the foreign body.  Using a burr drill is 
also an option, but this device is less commonly available and may lead to significant epithelial 
damage.   
 
The vast majority of corneal foreign bodies are metallic [3] and thus are frequently 
ferromagnetic.  Consequently, it may be possible to use a magnet to remove most corneal foreign 
bodies.  The use of a magnet has been described for removal of soft tissue foreign bodies [5,6] 
and nasal foreign bodies [7], but the use of a magnet to remove corneal foreign bodies in the ED 
has not been studied.  In a letter to the editor [4], it was suggested that magnetized forceps might 
be used to remove a corneal foreign body, but this technique never became commonplace.   
 
There is literature supporting magnetic extraction of intraocular metallic foreign bodies [8,9,10].   
 
Thus, we propose a prospective study to assess the effectiveness of a rare earth magnet to 
remove corneal foreign bodies. 
 
 
Methods 
 
This will be a prospective interventional study to assess the use of a rare earth magnet for the 
removal of corneal foreign bodies.  Patients may be included if they are over 18, and present to 
the emergency department with a metallic corneal foreign body.  Patients will be excluded if they 
are prisoners, pregnant women, have pacemakers, have metallic facial implants, or if there is any 
suspicion of a globe rupture. 
 
After the patient sign written, informed consent, the physician will attempt to remove the corneal 
foreign body with an N45 3” x 1/2" x 1/4" Neodymium bar magnet OR the North by Honeywell 
326734G Eye Magnet with Loop.  The treating physician will make sure that there are no 
magnetic objects within one foot of the patient’s eye while the magnet is being used for this 
procedure.  If the physician is unable to remove the corneal foreign body with the magnet, he or 
she may proceed with standard care. 
Only the investigators of the study who have established an agreed upon method for this 
technique will be allowed to perform this procedure.  The patient will be asked to remove any 
metallic nose, ear, or facial jewelry prior to the procedure.  The approach should be parallel to 
the floor and at the height of the foreign body.  This approach should minimize the risk of the 
foreign body sliding on the surface of the eye.  The magnet will be brought next to the foreign 
body and then it will gently touch the foreign body.  If that does not result in the foreign body 
latching onto the magnet, the attempt to remove the foreign body with the magnet will be 
discontinued.   

 
The treating physician will fill out a brief data collection form for each patient including the 
patient’s age and gender, the type of substance thought to be on the patient’s cornea, the time 
since the incident, whether or not the technique was successful, whether or not there was 
increased fluorescein uptake after the attempt with the magnet, whether or not the patient 
experienced discomfort with the procedure, and (if the magnet did not remove the corneal 
foreign body) other techniques used to remove the corneal foreign body. 
 
The primary outcome will be the percentage of patients with metallic corneal foreign bodies in 
whom the foreign body was successfully removed.  Secondarily, we will assess to see if this 
technique results in any adverse outcomes such as discomfort to the patient or epithelial damage 
to the surface of the eye.  As this technique has never before been studied in the ED, we intend to 
enroll 10-20 patients. 
 
 
 
References 
 
1. Babineau MR, Sanchez LD. Ophthalmologic procedures in the emergency department. Emerg 
Med Clin North Am. 2008 Feb. 26(1):17-34, v-vi. 
 
2. Roberts JR, Hedges RJ. Ophthalmologic procedures. Clinical Procedures in Emergency 
Medicine. 4th ed. Philadelphia, Pa: WB Saunders; 2014. 1259-97. 
 
3. Macedo Filho ET, Lago A, Duarte K, Liang SJ, Lima AL, Freitas D. Superficial corneal 
foreign body: laboratory and epidemiologic aspects. Arq Bras Oftalmol. 2005 Nov-Dec. 
68(6):821-3. 
 
4.  Arnold RW, Erie JC. Magnetized Forceps for Metallic Corneal Foreign Bodies. Arch 
Ophthalmol. 1988;106(11):1502. doi:10.1001/archopht.1988.01060140670007. 
5.  Bocka JJ, Godfrey J. Emergency Department Use of an Eye Magnet for the Removal of Soft 
Tissue Foreign Bodies. Ann Emerg Med. 1994;23:350-351. 
6. Sarihan A, Can Cagdas. A case series featuring soft tissue foreign body removal with 
magnet in ED settings. American Journal of Emergency Medicine. 2014.32(8):952.e3-952.e5.  
7. Douglas SA, Mirza S, Stafford FW. Magnetic removal of a nasal foreign body. Int. J. Pediatr. 
Otorhinolaryngol. 2002. 62:165–167. 
8.  Coleman DJ, Lucas BC, Rondeau MJ, Chang S.  Management of Intraocular Foreign Bodies. 
Ophthamology. 1987.94(12):1647-1653.  
9.  Chiquet C, Zech JC, Gain P, Adeleine P, Trepsat C. Visual outcome and prognostic factors 
after magnetic extraction of posterior segment foreign bodies in 40 cases.  Br J Ophthalmol. 
1998;82:801–806.  

10.Venkatesh P, Keshavamurthy R, Verma L, Tewari HK. Removal of metallic intraocular 
foreign body impacted in the retina by magnetizing the mvr blade using an external magnet. Clin 
Experiment Ophthalmol. 2003;31:451–452.