Retinal pigment epithelium–choroid and retinal photoreceptor cells

The retinal pigment epithelium (RPE)–choroid and retinal photoreceptor cells constitute a vital functional unit within the posterior segment of the eye (NIH, 2023). The RPE serves as a metabolic gatekeeper, facilitating the transport of nutrients and oxygen from the vascular choroid to the high-demand photoreceptor cells while simultaneously removing metabolic waste (StatPearls, 2023). It plays a central role in the visual cycle by regenerating 11-cis-retinal and maintains retinal homeostasis through the phagocytosis of shed photoreceptor outer segments (PubMed, PMID: 28934390). Pathological changes in this complex, such as the accumulation of lipofuscin or the development of choroidal neovascularization, are hallmark features of age-related macular degeneration and various inherited retinal dystrophies (PubMed, PMID: 31430510). While this complex is an anatomical region rather than a single protein, it is the primary site for advanced ocular therapies, including intravitreal anti-VEGF injections and subretinal gene therapy (FDA, 2017). Effective treatment strategies often aim to preserve the integrity of the RPE-photoreceptor interface to prevent irreversible vision loss (PubMed, PMID: 37556258).

Other names

RPE-choroid complexOuter retinal layersSubretinal spaceRetinal pigment epitheliumPhotoreceptor cellsChoriocapillaris-RPE-photoreceptor unit

Therapeutic agents targeting this complex act through various mechanisms, including the inhibition of vascular endothelial growth factor (VEGF) to treat neovascularization, modulation of the complement pathway to slow geographic atrophy, and viral-mediated gene delivery to replace defective proteins in the RPE or photoreceptors (PubMed, PMID: 31430510; FDA, 2023).