Predictive factors of visual outcome in posterior segment intraocular foreign body

Background: To identify the predictive factors for visual outcomes of patients with posterior segment intraocular foreign body (IOFB) after open-globe injury. Methods: A retrospective, interventional study was conducted to evaluate consecutive patients with retained posterior segment IOFB who underwent vitrectomy over a 10-year period from 2007 to 2016. Multivariate linear regression analysis was used to identify the potential predictive factors for final visual outcomes. Results: Forty-two patients were evaluated, with predominantly males (97.6%) and mean age 37.21 years. Hammering on metal (47.62%) was the major mechanism of injury. The majority of foreign bodies were metallic (95.24%) with a mean dimension of 4.3 mm. Twenty-four (57.14%) patients initially presented with a Snellen visual acuity <6/60. After surgery, 19 (45.24%) eyes had final visual outcomes of 6/12 or better; however, visual outcomes worse than 6/60 were documented in 17 (40.48%) eyes. Multivariate linear regression analysis revealed that the occurrence of retinal detachment (RD; p<0.01) and larger IOFB dimension (p=0.02) independently predicted worse final visual outcomes after adjusting for age and initial VA. Eyes with entry wounds located posteriorly into the sclera significantly increased the risk of RD compared to eyes with entry wounds involving cornea only (p=0.03). There was no association between time interval for IOFB removal and development of endophthalmitis. Conclusion: RD and larger IOFB dimension are significant predictive factors associated with worse final visual outcomes. Increased time to IOFB removal is not associated with either a higher risk of endophthalmitis or worse visual outcomes.