Zinc in eye health, retinal biology and disease

Zinc is an essential trace mineral that plays a crucial role in numerous bodily functions, including immune response, wound healing, and protein synthesis. Regarding eye health, zinc is particularly important due to its high concentration, functional abundance, and critical roles in the retina/RPE/choroid complex, where both deficiency and excess can lead to cellular dysfunction. This mineral contributes significantly to the maintenance of the structure and function of the tissues, and it is believed to help protect against oxidative stress, which can damage cells in the eye. The retinal pigment epithelium/choroid complex (RPE/choroid) contains the highest zinc concentration. Therefore, it is unsurprising that several eye disorders associated with this interface are associated with reduced zinc accumulation, and zinc supplementation has become an essential secondary preventive therapy for diseases like age-related macular degeneration (AMD). Despite zinc's importance in health and diseases of the outer retina, it still needs to be fully understood how zinc participates in cellular and molecular events and how zinc supplementation might be beneficial. However, it appears that adequate zinc levels are essential for retinal health and overall vision, particularly as we age. This review is focused on summarising our current understanding of the biology of zinc, with particular attention paid to the RPE/choroid interface.