Units of Measurement
Visual acuity does not increase linearly!
– but logarithmically – in relation to the size of the visual elements.
When testing visual acuity, a logarithmic scale is used to grade the size of the letters or symbols on the chart, so they become smaller and smaller in a logarithmic progression.
The logarithmic scale allows for a more sensitive evaluation of visual acuity and helps detect even small changes in vision. This is especially important in clinical practice, where accurate measurements of visual acuity are crucial for proper screening and referral of vision-related issues.
The “old” units of measurement are still present on the charts from ISOeyes.
This makes the transition from the old recording method to the new one more understandable.
