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Tunable lenses can minimize visual flicker by adjusting optical power. This novel flicker-minimization task is repeatable, fast, and bypasses accommodation, suggesting new eye refractive error measurement methods.

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Area of Science:

  • Ophthalmology
  • Visual Perception
  • Optical Engineering

Background:

  • Tunable lenses offer dynamic optical power adjustment, finding increasing use in ophthalmic applications.
  • Periodic defocus changes can induce perceptual effects like flicker and chromatic distortion.

Purpose of the Study:

  • To evaluate the human visual system's response to periodic defocus changes using tunable lenses.
  • To investigate a flicker-minimization task for refractive error assessment.
  • To compare flicker-minimization with blur-minimization tasks and assess the role of accommodation.

Main Methods:

  • 25 subjects used tunable lenses to minimize perceived flicker from a chromatic stimulus with 0.25D amplitude and 15 Hz frequency.
  • Subjects also performed a blur-minimization task with a black-and-white stimulus.
  • The effect of cycloplegia on both tasks was evaluated.

Main Results:

  • The flicker-minimization task showed higher repeatability (±0.17D) than blur-minimization (±0.49D) and was faster (38s per repetition).
  • Cycloplegia impaired blur-minimization but not flicker-minimization, indicating defocus flicker deactivates accommodation.
  • Flicker perception varied with overall defocus levels.

Conclusions:

  • Defocus flicker deactivates the accommodative system, offering a new avenue for objective refractive error measurement.
  • The flicker-minimization task demonstrates potential for accurate, precise, and rapid eye refractive error assessment.
  • This method may improve upon existing subjective eye examination techniques, potentially reducing the need for direct supervision.