title: Small saccades serve no useful purpose: reply to a letter by R. W. Ditchburn.
mesh_terms: D005133:Eye Movements; D005403:Fixation, Ocular; D006801:Humans; D010827:Physiology; D012438:Saccades; D013997:Time Factors; D014792:Visual Acuity; D014796:Visual Perception