Visual Acuity Converter — Complete User Guide
Complete conversion for decimal/logMAR/fractional/Min of Arc visual acuity, with standard acuity chart reference, suitable for both research and clinical use.
visual acuity conversiondecimal acuitylogMARSnellenfractional acuityMin of Arc
Visual Acuity Notation Systems
Decimal Acuity (Common in China/Japan)
Expressed as decimal, with 1.0 as standard normal vision.
LogMAR Acuity (International Research Standard)
LogMAR = log10(1/decimal acuity)
- Normal vision (1.0) → LogMAR = 0.00
- 0.5 vision → LogMAR = 0.30
- 0.1 vision → LogMAR = 1.00
Fractional Acuity (Common in US/Europe)
Such as 20/20 (feet), 6/6 (meters).
Conversion Table
| Decimal | LogMAR | Fraction(ft) | Fraction(m) |
|---|---|---|---|
| 1.0 | 0.00 | 20/20 | 6/6 |
| 0.5 | 0.30 | 20/40 | 6/12 |
| 0.3 | 0.52 | 20/67 | 6/20 |
| 0.1 | 1.00 | 20/200 | 6/60 |
Clinical Applications
- Research papers: Unified use of LogMAR facilitates statistical analysis
- Pediatric refraction: logMAR eliminates "crowding effect" influence
- Low vision assessment: Decimal notation is more sensitive to logarithmic changes
Precautions
- Higher LogMAR values indicate worse vision, opposite to decimal acuity
- Testing environment brightness should meet standards (300-500 lux)