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Noticeable, troublesome and objectionable limits of blur
David A Atchison1, Scott W Fisher, Carol A Pedersen
1School of Optometry, Queensland University of Technology, Victoria Park Road, Kelvin Grove, QLD 4059, Australia. d.atchison@qut.edu.au
Vision Research
|April 12, 2005
Summary
This study determined how much induced blur is noticeable, troublesome, or objectionable. Blur perception varied with letter size and pupil diameter, impacting visual comfort and clarity.
Area of Science:
- Optometry and Vision Science
- Human Visual Perception
Background:
- Visual blur significantly impacts reading performance and visual comfort.
- Understanding the thresholds for noticeable, troublesome, and objectionable blur is crucial for designing visual aids and evaluating visual quality.
Purpose of the Study:
- To quantify the dioptric limits of induced blur that are perceived as noticeable, troublesome, or objectionable.
- To investigate the influence of letter size and artificial pupil diameter on these blur thresholds.
Main Methods:
- 15 subjects with cyclopleged eyes were tested using a Badal optometer.
- High-contrast letter targets of varying sizes (0.0-0.7 logMAR) were presented through artificial pupils (3-6 mm).
- Participants reported their perception of blur at different levels.
Main Results:
- Noticeable blur limits varied with pupil size (3-6 mm) and letter size (0.0-0.7 logMAR).
- Larger letter sizes (0.7 logMAR) significantly increased noticeable blur limits by ~70% compared to smallest letters (0.0 logMAR).
- Troublesome and objectionable blur limits were approximately 1.6-1.8 and 2.1-2.5 times higher than noticeable limits, respectively.
Conclusions:
- Letter size significantly influences the perception of induced blur.
- Criteria for troublesome and objectionable blur appear relatively consistent across different letter sizes.
- Findings provide valuable data for visual optics and the development of visual standards.