Blindness, CorticalVision TestsVision DisordersVisually Impaired PersonsVisual CortexEvoked Potentials, VisualVision, LowVisual AcuityBlindnessVisual PerceptionVisual PathwaysVisual FieldsPhotic StimulationRefractive ErrorsEye DiseasesOccipital LobeContrast SensitivityEducation of Visually DisabledCataractPattern Recognition, VisualVision ScreeningMotion PerceptionBrain MappingMagnetic Resonance ImagingSensory AidsOnchocerciasis, OcularEyeglassesAttentionSpace PerceptionPsychophysicsPrevalenceFixation, OcularGlareMacacaOptometryParietal LobeCataract ExtractionReaction TimeMacular DegenerationVision, Ocular