The term LogMAR is an acronym for the Logarithm of the Minimum Angle of Resolution. … The letter size is described in LogMAR units where LogMAR 0.00 is equivalent to 6/6 (20/20) and LogMAR 1.00 is equivalent to 6/60 (20/200).
What is logMAR value?
Each letter has a score value of 0.02 log units. Since there are 5 letters per line, the total score for a line on the LogMAR chart represents a change of 0.1 log units. The formula used in calculating the score is: LogMAR VA = 0.1 + LogMAR value of the best line read – 0.02 X (number of optotypes read)
How do you read a logMAR chart?
- Ask patient to read down chart with one eye covered.
- Note how many letters are read correctly until none of the letters on a line are.
- read correctly.
- Read off vision score from chart.
- Repeat with pinhole if the vision is worse than 0.2.
- If logMAR vision is worse than 1.0, retest at 2m or 1m (see over page)
