Contact lens-related complications in austere conditions among military personnel: a systematic review

INTRODUCTION: Military service personnel are required to deploy to austere environments where they are exposed to harsh conditions. Many service personnel continue to wear contact lenses when deployed as they are an effective alternative to spectacles by affording superior ergonomic functionality, although they are associated with significant complications. We aimed to explore the prevalence and type of contact lens-related complications among deployed service personnel worldwide. METHODS: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 statement. PubMed, Medline, CINAHL and EMBASE databases were searched for relevant articles published between 1950 and 2023. The keywords 'contact lens' and 'military' or 'army' or 'navy' or 'air force' and 'austere' or 'deployed' or 'adverse' were used. RESULTS: Five eligible articles were included. Excluded articles reported contact lens wear in the firm base, were not related to military personnel or did not involve the deployed setting. Major complications associated with contact lens wear included microbial keratitis and contact lens-related discomfort. Excluding case reports, the overall incidence of contact lens-related complications ranged from 0.35% to 25.4%. The three case reports included in this systematic review described Acanthamoeba keratitis, Nocardia keratitis and contact lens-related discomfort as significant complications. These case reports also detailed time to initial presentation and type of contact lens worn when complications were encountered. Types of deployed conditions service personnel were exposed to included desert, temperate and underwater environments. CONCLUSIONS: We highlight a scarcity of recent data regarding contact lens-related complications in the deployed setting. While contact lens-wearing service personnel are at risk of infectious keratitis and contact lens-related discomfort, we recommend good-quality data collection on contact lens wearing schedules and complication rates to steer guidance on contact lens wear in service personnel.