Comparison of External Magnet and Intraocular Forceps for Intravitreal Foreign Body Extraction

Purpose: To compare the adverse events after the use of 2 conventional methods of magnetic intravitreal foreign body (IVFB) extraction and to identify the prognostic factors in a series of patients with retained IVFB. Design: Retrospective comparative interventional case series. Participants: Seventy-one eyes of 71 patients with IVFB undergoing foreign body extraction. Methods: A retrospective review was conducted on a consecutive series of patients undergoing vitrectomy, IVFB extraction, and other necessary vitreoretinal procedures. On the basis of the method of IVFB extraction, the eyes were categorized into 2 groups: group 1 (intraocular forceps extraction of IVFB [n = 30 eyes]) and group 2 (external magnet extraction of IVFB [n = 41 eyes]). Main Outcome Measures: The rate of retinal break formation, the rate of development of retinal detachment (RD), and the change in visual acuity were observed. Univariate and multivariate analyses of a number of potential prognostic factors were undertaken. Results: The overall rate of retinal break formation and development of RD was 41% and 7%, respectively. There was no significant difference between the 2 methods of IVFB extraction in relation to retinal break formation (group 1, 43%; group 2, 39%) and development of postoperative RD (group 1, 6.6%; group 2, 7.3%). However, 3 cases of giant retinal dialysis occurred in group 1 (P = 0.021). According to multivariate regression analysis, the factors predictive of poor visual outcome were the following: (1) longer duration between injury and FB extraction (P = 0.006), (2) lower preoperative visual acuity (P = 0.02), and (3) presence of afferent pupillary defect (P = 0.043). Conclusions: The data from this study suggest no preference between external magnet and intraocular forceps for the extraction of magnetic IVFB. However, the use of external magnet for the extraction of IVFB may offer several advantages, including easier surgical handling and, as a result of decreased intraocular manipulation, the lower rate of giant retinal dialysis formation.