[Selection of Chinese characters for visual acuity charts using psychophysical methods]

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Context:

• Developing accurate visual acuity charts is crucial for diagnosing vision impairments.
• Traditional methods for selecting characters may not fully account for visual perception factors.
• Chinese characters present unique challenges due to their complex structures.

Purpose:

• To investigate the use of psycho-physical methods for selecting legible Chinese characters for visual acuity charts.
• To objectively select Chinese characters based on visual acuity (VA) thresholds and slopes derived from Fourier frequency analysis.
• To determine optimal character sets for both lower and medium stroke-number Chinese visual acuity charts.

Summary:

• Twenty-eight subjects participated in reading tests with 37 selected Chinese characters presented at various sizes.
• Weibull function analysis determined visual acuity thresholds and slopes for each character.
• Ten characters were selected for a lower stroke-number chart (VA threshold: 5.84 ± 0.36 arc) and ten for a medium stroke-number chart (VA threshold: 8.38 ± 0.24 arc).

Impact:

• The study provides an objective, Fourier frequency-based method for selecting Chinese characters for visual acuity charts.
• The identified character sets can enhance the accuracy and legibility of Chinese visual acuity testing.
• This research contributes to the development of more effective tools for vision assessment in Chinese populations.