The aim of the study is to apply a novel clinical investigation protocol in patients with Phosphodiesterase 6A (PDE6A), PDE6B and Rhodopsin (RHO)-based retinitis pigmentosa. This novel, multimodal clinical examination protocol describes and correlates structural, functional and metabolic aspects during natural disease development. Test-retest variability of new measurements as well as correlations of the structural, functional, and metabolic changes will be defined to be able to define well-suited readouts for safety and efficacy of future treatment developments before they reach the clinical phase.