Exploring retinal microglia: development, degeneration, and iPSC-derived model systems.

Microglia are key regulators of retinal development, immune surveillance, and neuroprotection. Derived from yolk sac progenitors, they exhibit precise laminar distribution within the retina and fulfill diverse physiological roles, including synaptic pruning, phagocytosis, and modulation of inflammation and angiogenesis. In retinal diseases such as retinitis pigmentosa, age-related macular degeneration, and diabetic retinopathy, microglial activation contributes to neurodegeneration and pathological remodeling. This review summarizes recent advances in our understanding of retinal microglial ontogeny, distribution, and function, with particular emphasis on human pluripotent stem cell (hPSC)-derived microglia (iMG) .We highlight in vitro and chimeric iMG-based models that facilitate human-specific studies and discuss their emerging applications in retinal disease modeling, therapeutic screening, and personalized medicine.