LogMAR ⇄ Snellen Visual Acuity Converter

Maps the patient's distance visual acuity (best-corrected, better eye, presenting acuity) to its LogMAR equivalent and the WHO 2019 ICD-11 visual-impairment category. Single common reference for documentation, DVLA decisions, certification of vision impairment (CVI), and study endpoints. LogMAR = log₁₀(1 / decimal acuity); each step on a standardised ETDRS chart is 0.10 log units (5 letters).