Correction of Saccade-Induced Midline Errors in Responses to Pure Disparity Vergence Stimuli.

  • John L. Semmlow Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey (UMDNJ), New Brunswick, New Jersey USA, Rutgers University, Piscataway, New Jersey USA
  • Yung-Fu Chen Department of Computer Science and Information Engineering, Dayeh University, Changhua, Taiwan
  • Bérangère Granger-Donnetti Essilor International, St. Maur, FRANCE
  • Tara L. Alvarez Department of Biomedical Engineering, New Jersey Institute of Technology (NJIT), Newark, New Jersey, USA
Keywords: vergence, saccade, oculomotor control, binocularity, saccade-vergence interaction


Purely symmetrical vergence stimuli aligned along the midline (cyclopean axis) require only a pure vergence response. Yet, in most responses saccades are observed and these saccades must either produce an error in the desired midline response or correct an error produced by asymmetry in the vergence response. A previous study (Semmlow, et al. 2008) has shown that the first saccade to appear in a response to a pure vergence stimulus usually increased the deviation from the midline, although all subjects (N = 12) had some responses where the initial saccade corrected a vergence induced midline error. This study focuses on those responses where the initial saccade produces an increased midline deviation and the resultant compensation that ultimately brings the eyes to the correct binocular position. This correction is accomplished by a higher level compensatory mechanism that uses offsetting asymmetrical vergence and/or corrective saccades. While responses consist of a mixture of the two compensatory mechanisms, the dominant mechanism is subject-dependent. Since fixation errors are quite small (minutes of arc), some feedback controlled physiological process involving smooth eye movements, and possibly saccades, must move the eyes to reduce binocular error to fixation disparity levels.
How to Cite
Semmlow, J. L., Chen, Y.-F., Granger-Donnetti, B., & Alvarez, T. L. (2009). Correction of Saccade-Induced Midline Errors in Responses to Pure Disparity Vergence Stimuli. Journal of Eye Movement Research, 2(5).