Methods: By reviewing charts of the RP patients, the investigators will categorize RP patients into different types according to the loci of the pathological change in their retina evaluated by opththaomoscopy. And the investigators will collect the data of their visual functions including visual acuity, visual field, Arden ratio of electrooculography, and color sense discrimination. Then, according to the OCT map, the investigators will analyze the retinal thickness by dividing the macular area into foveal area, inner ring and outer ring. Finally, the investigators will analyze the relationships between visual functions and retinal thickness in different macular areas in different types of RP patients.