title: Abnormal Fixational Eye Movements in Amblyopia.
abstract: OBJECTIVE
  Fixational saccades shift the foveal image to counteract visual fading related to neural adaptation. Drifts are slow eye movements between two adjacent fixational saccades. We quantified fixational saccades and asked whether their changes could be attributed to pathologic drifts seen in amblyopia, one of the most common causes of blindness in childhood.
  
  
  METHODS
  Thirty-six pediatric subjects with varying severity of amblyopia and eleven healthy age-matched controls held their gaze on a visual target. Eye movements were measured with high-resolution video-oculography during fellow eye-viewing and amblyopic eye-viewing conditions. Fixational saccades and drifts were analyzed in the amblyopic and fellow eye and compared with controls.
  
  
  RESULTS
  We found an increase in the amplitude with decreased frequency of fixational saccades in children with amblyopia. These alterations in fixational eye movements correlated with the severity of their amblyopia. There was also an increase in eye position variance during drifts in amblyopes. There was no correlation between the eye position variance or the eye velocity during ocular drifts and the amplitude of subsequent fixational saccade. Our findings suggest that abnormalities in fixational saccades in amblyopia are independent of the ocular drift.
  
  
  CONCLUSIONS
  This investigation of amblyopia in pediatric age group quantitatively characterizes the fixation instability. Impaired properties of fixational saccades could be the consequence of abnormal processing and reorganization of the visual system in amblyopia. Paucity in the visual feedback during amblyopic eye-viewing condition can attribute to the increased eye position variance and drift velocity.
authors.affiliation: Daroff-Del'Osso Ocular Motility Laboratory, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, United States of America.|Department of Neurology, Case Western Reserve University, Cleveland, Ohio, United States of America.|Neurology Service, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, United States of America.
authors.forename: Aasef G
authors.initials: AG
authors.lastname: Shaikh
authors.affiliation: Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America.
authors.forename: Jorge
authors.initials: J
authors.lastname: Otero-Millan
authors.affiliation: Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Daroff-Del'Osso Ocular Motility Laboratory, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, United States of America.|Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America.
authors.forename: Fatema F
authors.initials: FF
authors.lastname: Ghasia
mesh_terms: D000550:Amblyopia / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D005123:Eye / Q000503:physiopathology*; D005133:Eye Movements; D005403:Fixation, Ocular; D006801:Humans; D012438:Saccades; D013285:Strabismus / Q000503:physiopathology; D014792:Visual Acuity