May 2003
Volume 44, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2003
Accommodative Tracking is Attenuated in Myopia
Author Affiliations & Notes
  • F.A. Vera-Diaz
    New England College of Optometry, Boston, MA, United States
  • N.C. Strang
    Dept of Optometry, University of Bradford, Bradford, United Kingdom
  • B. Winn
    Dept of Optometry, University of Bradford, Bradford, United Kingdom
  • J. Gwiazda
    Dept of Optometry, University of Bradford, Bradford, United Kingdom
  • Footnotes
    Commercial Relationships  F.A. Vera-Diaz, None; N.C. Strang, None; B. Winn, None; J. Gwiazda, None.
  • Footnotes
    Support  NIH/NEI Grant EY01191
Investigative Ophthalmology & Visual Science May 2003, Vol.44, 3116. doi:
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    • Get Citation

      F.A. Vera-Diaz, N.C. Strang, B. Winn, J. Gwiazda; Accommodative Tracking is Attenuated in Myopia . Invest. Ophthalmol. Vis. Sci. 2003;44(13):3116.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Abstract: : Purpose: Myopic subjects have reduced accommodative accuracy under steady-state viewing conditions. In addition, they have reduced dynamic responses to step-wise changes in stimulus vergence following a period of sustained viewing. In this study the closed-loop accommodation response to sinusoidally-modulated changes in stimulus vergence (accommodation tracking) is measured in an attempt to investigate the relationship between temporal frequency and accommodation inaccuracy in myopia. Methods: Monocular closed-loop accommodation responses were measured in a group of emmetropes (n=6) and myopes (n=6) using a dynamic tracking infrared optometer (SRI). A high contrast photopic (30cdm-2) stimulus was presented in a Badal optometer, viewed through a 5mm Maxwellian fixed pupil, and modulated sinusoidally (0.05-0.5Hz) over a 2D range (2D-4D). Power spectrum analysis was used to calculate gain and phase. Results: Emmetropic subjects demonstrated a typical reduction in gain and an increased phase lag at higher temporal frequencies. Myopic grouped mean data showed a significant decrease in accommodative gain compared to emmetropes (p<0.01) which was not temporal frequency dependent. Myopes also exhibited an increased phase lag compared to emmetropes at all temporal frequencies (p<0.01). Conclusions: Blur-driven accommodative tracking is attenuated across all temporal frequencies in myopia. A similar level of myopic accommodation inaccuracy was found at all temporal frequencies.

Keywords: myopia • accommodation 
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