Night BlindnessBlindnessXerophthalmiaEye Diseases, HereditaryElectroretinographyVitamin A DeficiencyGenetic Diseases, X-LinkedDark AdaptationNepalBlindness, CorticalRetinitis PigmentosaVitamin AMyopiaRetinal Rod Photoreceptor CellsRhodopsinNight CarePedigreeAlbinism, OcularRetinal DiseasesRetinaVisual AcuityRetinal Bipolar CellsVision, LowRetinal DegenerationFundus OculiEye DiseasesGenes, RecessiveX ChromosomeRetinal Cone Photoreceptor CellsOnchocerciasis, OcularPregnancy ComplicationsElectrooculographyMutationEye ProteinsPhotoreceptor CellsTRPM Cation ChannelsCataractG-Protein-Coupled Receptor Kinase 1ArrestinGenetic LinkagePhotoreceptor Cells, VertebrateDNA Mutational AnalysisVisually Impaired Personsbeta CaroteneConsanguinityVision, OcularLightSensory ThresholdsCircadian RhythmMutation, MissenseCalcium Channels, L-Type