Ballistic Eye Protection: Why Are Soldiers Reluctant to Use Them?

INTRODUCTION

The Israel Defense Forces (IDF), as well as many other armies, faces major challenges in balancing the need to protect soldiers from harm while not impeding their ability to fight. Eye protections available in the IDF are underused, for reasons that are as yet unclear. In this study, we aim to gain a better understanding of the influence of eye protection currently in use in the IDF on vision.

MATERIALS AND METHODS

In this cross-sectional study, subjects were assessed for best corrected visual acuity, contrast sensitivity, and binocular visual fields (Goldmann) in a crossover design (with and without eye protection). In addition, we established a comprehensive review on the subjective faults of the eye protection, both from personal experiences of soldiers who used them during their military service and from civilian volunteers who used them in a sterile laboratory setting.

RESULTS

Visual acuity, contrast sensitivity and visual fields with and without the eye protection were assessed in 25 subjects. Eye protection did not cause any statistically significant change in visual acuity. However, the eye protection caused a statistically significant decrease in visual fields in all quadrants and in both isopters used.

CONCLUSIONS

Significant restriction of the visual field can pose a major challenge for soldiers on the battlefield. The use of eye protection with wider lenses or no frame should be considered. Education and instruction should focus on increasing awareness among commanders and soldiers of the benefits of eye protection and fostering trust in the technology's capabilities. In parallel, it is crucial to educate soldiers about its disadvantages, and how such disadvantages can be overcome. We stipulate the findings to the standard IDF goggle and might not apply to other designs.

Topogram-based tube current modulation of head computed tomography for optimizing image quality while protecting the eye lens with shielding

BACKGROUND

Multiple rounds of head computed tomography (CT) scans increase the risk of radiation-induced lens opacification.

PURPOSE

To investigate the effects of CT eye shielding and topogram-based tube current modulation (TCM) on the radiation dose received by the lens and the image quality of nasal and periorbital imaging.

MATERIAL AND METHODS

An anthropomorphic phantom was CT-scanned using either automatic tube current modulation or a fixed tube current. The lens radiation dose was estimated using cropped Gafchromic films irradiated with or without a shield over the orbit. Image quality, assessed using regions of interest drawn on the bilateral extraorbital areas and the nasal bone with a water-based marker, was evaluated using both a signal-to-noise ratio (SNR) and contrast-noise ratio (CNR). Two CT specialists independently assessed image artifacts using a three-point Likert scale.

RESULTS

The estimated radiation dose received by the lens was significantly lower when barium sulfate or bismuth-antimony shields were used in conjunction with a fixed tube current (22.0% and 35.6% reduction, respectively). Topogram-based TCM mitigated the beam hardening-associated artifacts of bismuth-antimony and barium sulfate shields. This increased the SNR by 21.6% in the extraorbital region and the CNR by 7.2% between the nasal bones and extraorbital regions. The combination of topogram-based TCM and barium sulfate or bismuth-antimony shields reduced lens doses by 12.2% and 27.2%, respectively.

CONCLUSION

Image artifacts induced by the bismuth-antimony shield at a fixed tube current for lenticular radioprotection were significantly reduced by topogram-based TCM, which increased the SNR of the anthropomorphic nasal bones and periorbital tissues.