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Objective changes in astigmatism during accommodation.

Francisco Lara-Lacárcel1, Iván Marín-Franch1,2, Vicente Fernández-Sánchez1

  • 1Faculty of Optics and Optometry, University of Murcia, Murcia, Spain.

Ophthalmic & Physiological Optics : the Journal of the British College of Ophthalmic Opticians (Optometrists)
|August 20, 2021
PubMed
Summary
This summary is machine-generated.

Astigmatism changes little with accommodation and convergence, except at high demands. Small shifts in the crystalline lens may cause minor changes in astigmatism power and axis.

Keywords:
accommodationaccommodative astigmatismastigmatismmonocular convergence

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Area of Science:

  • Ophthalmology
  • Optometry
  • Vision Science

Background:

  • Previous research indicates minor astigmatism changes during eye accommodation.
  • Ocular cyclotorsion occurs at various gaze angles.
  • Accommodation and convergence typically happen together.

Purpose of the Study:

  • To investigate how astigmatism magnitude and axis change with accommodation at different convergence angles.
  • To understand the interplay between accommodation, convergence, and astigmatic changes in the human eye.

Main Methods:

  • Evaluated 15 subjects (20-49 years) with ≤1.5 D astigmatism.
  • Used a Shack-Hartmann aberrometer for accommodation from +0.50 D to -10 D.
  • Measured astigmatic changes at convergence demands of 0°, 5°, 10°, and 15°.

Main Results:

  • No significant change in Jackson cross-cylinder J45 component during accommodation.
  • J0 component shifted slightly with accommodation, varying with convergence demand.
  • Average cylinder power changed by -0.05 D/Dacc to -0.08 D/Dacc, with axis shifting towards against-the-rule.

Conclusions:

  • Clinically significant astigmatism changes were not observed for accommodation demands up to 4 D with convergence up to 15°.
  • Minor astigmatic shifts may result from crystalline lens displacement during accommodation.
  • Age did not significantly influence astigmatic changes in this study.