The cilia of cells constituent to the retina are fundamental to vision. Of the ∼250 genes causative of inherited retinal degeneration, 20% mediate functions related to photoreceptor primary cilium formation, structure or function. Primary cilia are sensory and signalling organelles emanating from the plasma membrane of most cells. They regulate a variety of biological processes, including left/right body axis asymmetry, limb patterning, central nervous system development and sensation. Cilia function by forming a specialised region of plasma membrane which concentrates specific signalling components, such as for sonic hedgehog signalling and phototransduction. Here, we review the roles of ciliary signalling and trafficking pathways in retinal biology and disease with a focus on the potential of non-rodent, metazoan experimental models for shedding light on these processes.
