Target spatial frequency determines the response to conflicting defocus- and convergence-driven accommodative stimuli

Yuuki Okada, Kazuhiko Ukai*, James S. Wolffsohn, Bernard Gilmartin, Atsuhiko Iijima, Takehiko Bando

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Asthenopia, or visual fatigue, is a frequent complaint from observers of stereoscopic three-dimensional displays. It has been proposed that asthenopia is a consequence of anomalous oculomotor responses generated by conflict between accommodative and convergence stimuli. The hypothesis was examined by measuring accommodation and convergence continuously with a Shin-Nippon SRW5000 infrared autorefractor and a limbus tracking device. Subjects viewed a high contrast Maltese Cross target at three levels of Gaussian filter target blur under conditions of relatively low- and high-conflict between accommodation and convergence stimuli, the latter inducing the sensation of stereopsis. Under the low-conflict conditions accommodation was stable, but convergence-driven accommodation was dominant when the target was extremely blurred. Under the high-conflict conditions the role of convergence-driven accommodation increased systematically with the degree of target blur. It is proposed that defocus-driven accommodation becomes weak when the target comprises low spatial frequency components. Large accommodative overshoots to step stimuli that are not blurred or only mildly blurred were consistently observed and are attributed to the initial accommodative response being convergence-driven. Whereas the possibility that high-conflict conditions are a cause of asthenopia has been previously reported, this is the first evidence that they specifically affect accommodative responses while viewing stereoscopic displays. © 2005 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)475-484
Number of pages10
JournalVision Research
Issue number4
Early online date29 Sept 2005
Publication statusPublished - Feb 2006


  • accommodation
  • asthenopia
  • blur
  • convergence
  • cross-coupling
  • spatial frequency
  • stereoscopic display
  • three-dimensional display
  • visual fatigue


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