An often-overlooked health issue: The potential adverse effects of microplastics on the human ocular health

Microplastics (MPs) have been detected in human tissues and body fluids, triggering obvious toxicity to human health. However, the adverse effects of MPs on human ocular surface were usually ignored, but receiving increasing attention now. The human ocular surface, the outermost layer of the eye, acts as the mechanical barrier to exotic substances to minimize interior damage. Daily exposure to MPs was considered to increase risks of corneal injury. In this review, we summarized the sources which MPs are most likely to enter the ocular surface, explored the potential detrimental impact of MPs and their adherent contaminants, as well as the factors influencing the toxicity on the human ocular surface, and proposed strategies to reduce ocular surface exposure to MPs. The results showed that air, personal care products, and contact lenses are the main potential sources of MPs. Furthermore, additives and adsorbents contribute more toxicities, causing some ocular surface diseases like dry eye, pterygium, conjunctivitis, and keratitis. The polymer type, size, and degree of aging, as well as human activities and nature, are factors that affect the toxicity of MPs. Reducing plastic consumption, eliminating environmental MPs, and strengthening personal protection are important ways to reduce toxicity. Collectively, this review provides new insights into the impact of MPs on ocular surface and health risk prevention and control.