Visual Acuity Converter

Professional tool for converting between Snellen and logMAR notations

Important: Please enter only ONE value. Filling more than one field may produce incorrect results.

Snellen (6 m)

Snellen (20 ft)

logMAR

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Common Conversion Reference Table

Snellen (6 m)	Snellen (20 ft)	Decimal	logMAR (rounded)	logMAR (exact)	Low Vision Category

Notes:

CF = Counting Fingers, HM = Hand Motion, LP = Light Perception, NLP = No Light Perception
Low Vision Categories follow WHO ICD-10 classification combined with AHPO clinical table for CF/HM mappings
CF rows are derived using logMAR = log₁₀(60 ÷ distance in m)
For statistical use: HM ≈ 2.6 logMAR, LP ≈ 2.7, NLP = non-numeric (3.0 placeholder)
All conversions use the exact formula: logMAR = −log₁₀(decimal acuity). Non-standard inputs show exact computed values; nearest standard row is highlighted in the table.

Disclaimer: This tool is for educational and clinical reference purposes only.

Always verify conversions and use clinical judgment when interpreting visual acuity measurements. This tool does not replace professional medical assessment.

Privacy: All calculations are performed locally in your browser. No data is stored or transmitted.