Although much work in larger retinal samples is needed to investigate the nature and potential mechanisms of retinal inflammation in human AD, various studies in animal models of AD have also provided evidence and insights into retinal inflammation in this disorder. Ning and colleagues first established the correlation of neurodegeneration and inflammation in the retina of ADtg mice (Ning et al., 2008). Other studies have shown increased microgliosis and astrocytosis, infiltration of lymphocytes and monocytes, and upregulation of monocyte chemoattractant protein-1 (MCP-1) in multiple layers of the retina and choroid (Ning et al., 2008; Liu et al., 2009; Perez et al., 2009; Yang et al., 2013; Edwards et al., 2014; Tsai et al., 2014; Antes et al., 2015; Gao et al., 2015; Pogue et al., 2015). A recent study in 3xTg AD mice has further described morphological changes in retinal microglia, including increased microglial cell number, soma size, retraction and reorientation of microglial processes, and change in cell locations (Salobrar-Garcia et al., 2020).