Plastics are synthetic materials made from organic polymers that are ubiquitous in daily living and are especially important in the healthcare setting. However, recent advances have revealed the pervasive nature of microplastics, which are formed by degradation of existing plastic products. Although the impact on human health has yet to be fully characterised, there is increasing evidence that microplastics can trigger inflammatory damage, microbial dysbiosis, and oxidative stress in humans. Although there are limited studies investigating their effect on the ocular surface, studies of microplastics on other organs provide some insights. The prevalence of plastic waste has also triggered public outcry, culminating in the development of legislation aimed at reducing microplastics in commercial products. We present a review outlining the possible sources of microplastics leading to ocular exposure, and analyse the possible mechanisms of ocular surface damage. Finally, we examine the utility and consequences of current legislation surrounding microplastic regulation.

Retinal pigment epithelial (RPE) cell dysfunction is a key driving force of AMD. RPE cells form a metabolic interface between photoreceptors and choriocapillaris, performing essential functions for retinal homeostasis. Through their multiple functions, RPE cells are constantly exposed to oxidative stress, which leads to the accumulation of damaged proteins, lipids, nucleic acids, and cellular organelles, including mitochondria. As miniature chemical engines of the cell, self-replicating mitochondria are heavily implicated in the aging process through a variety of mechanisms. In the eye, mitochondrial dysfunction is strongly associated with several diseases, including age-related macular degeneration (AMD), which is a leading cause of irreversible vision loss in millions of people globally. Aged mitochondria exhibit decreased rates of oxidative phosphorylation, increased reactive oxygen species (ROS) generation, and increased numbers of mitochondrial DNA mutations. Mitochondrial bioenergetics and autophagy decline during aging because of insufficient free radical scavenger systems, the impairment of DNA repair mechanisms, and reductions in mitochondrial turnover. Recent research has uncovered a much more complex role of mitochondrial function and cytosolic protein translation and proteostasis in AMD pathogenesis. The coupling of autophagy and mitochondrial apoptosis modulates the proteostasis and aging processes. This review aims to summarise and provide a perspective on (i) the current evidence of autophagy, proteostasis, and mitochondrial dysfunction in dry AMD; (ii) current in vitro and in vivo disease models relevant to assessing mitochondrial dysfunction in AMD, and their utility in drug screening; and (iii) ongoing clinical trials targeting mitochondrial dysfunction for AMD therapeutics.

Age-related macular degeneration (AMD) is the leading cause of visual loss and affects millions of people worldwide. Dysfunction of the retinal pigment epithelium (RPE) is associated with the pathogenesis of AMD. The purpose of this work is to build and evaluate the performance of ultrathin scaffolds with an electrohydrodynamic jet (EHDJ) printing method for RPE cell culture. We printed two types of ultrathin (around 7 µm) polycaprolactone scaffolds with 20 μm and 50 μm pores, which possess mechanical properties resembling that of native human Bruch’s membrane and are biodegradable. Light microscopy and cell proliferation assay showed that adult human retinal pigment epithelial (ARPE-19) cells adhered and proliferated to form a monolayer on the scaffolds. The progress of culture matured on the scaffolds was demonstrated by immunofluorescence (actin, ZO-1, and Na+ /K+ -ATPase) and Western blot analysis of the respective proteins. The RPE cells cultured on EHDJ-printed scaffolds with 20 μm pores presented higher permeability, higher transepithelial potential difference, and higher expression level of Na+ /K+ -ATPase than those cultured on Transwell inserts. These findings suggest that the EHDJ printing can fabricate scaffolds that mimic Bruch’s membrane by promoting maturation of RPE cells to form a polarized and functional monolayered epithelium with potential as an in vitro model for studying retinal diseases and treatment methods