Homeostasis and dyshomeostasis of the retina

Retinal homeostasis is maintained through a network of the nervous, circulatory, endocrine and immune systems. The integrity of the blood-retinal barrier, immune-inflammatory responses, and metabolic changes all significantly affect the maintenance of normal visual function. Retinal degenerative diseases, which include age-related macular degeneration, retinitis pigmentosa, diabetic retinopathy, and other disorders, are a group of heterogeneous and multi-etiological diseases resulting in an irreversible visual impairment. Whether these disorders are inherited, acquired, or from systemic origins, the gradual loss of the retinal pigment epithelium (RPE) and/or retinal neurons is a common feat. This process often begins with compromised retinal integrity, followed by a disruption in the equilibrium of inflammation, immune response, metabolism, and other aspects, resulting in retinal dyshomeostasis that affects not only disease progression but also the effect of therapeutic intervention. Therefore, a comprehensive understanding of the retinal homeostasis and dyshomeostasis will assist the development of treatment strategies for retinal degenerative diseases and open new avenues for clinical translation.