Why I do this: you can't watch yourself improve if you don't measure. Blur is data, not a verdict.
- Far point: hold small print and move it away until it just starts to blur. Measure that distance in cm, for each eye separately.
- Convert it: 100 ÷ cm = your dioptres. (25 cm → −4.00 D.) My calculator in the Toolkit does this for you.
- Acuity: note your distance from a letter chart + the lowest line you can read easily.