Convert Visual Acuity Instantly
Visual acuity can be expressed in several different formats depending on whether it is being discussed in clinical research or everyday practice. Ophthalmologists and researchers commonly use LogMAR to measure vision with high precision, while most patients are more familiar with the traditional Snellen format, such as 20/20 vision.
This simple tool allows you to convert between LogMAR and Snellen visual acuity values quickly and accurately. It can be useful for interpreting clinical study data, understanding surgical outcome reports, or simply translating research measurements into a format that is easier to recognise.
London Vision Clinic
LogMAR ↔ Snellen Vision Converter
Convert LogMAR values into Snellen visual acuity and vice versa. This tool is useful for interpreting clinical outcomes and making visual acuity data easier to understand.
Convert LogMAR to Snellen
Enter a LogMAR value such as 0.00, -0.10 or 0.30.Convert Snellen to LogMAR
Enter a Snellen value in the format 20/20, 20/40 or 6/6.Common Visual Acuity Reference Guide
| LogMAR | Snellen | Clinical Interpretation |
|---|---|---|
| -0.10 | 20/16 | Better than standard 20/20 vision |
| 0.00 | 20/20 | Standard reference for normal visual acuity |
| 0.10 | 20/25 | Slightly reduced from 20/20 |
| 0.20 | 20/32 | Mild reduction in acuity |
| 0.30 | 20/40 | Common threshold for driving standards in some settings |
| 0.50 | 20/63 | Moderate reduction in acuity |
| 1.00 | 20/200 | Severe visual impairment range |
FAQs
What is LogMAR vision measurement?
LogMAR stands for Logarithm of the Minimum Angle of Resolution. It is a visual acuity measurement used widely in ophthalmology and clinical research because it provides a more precise and consistent way to measure vision compared with traditional Snellen fractions.
What is Snellen visual acuity?
Snellen visual acuity is the familiar format used in eye tests, typically expressed as fractions such as 20/20 or 20/40. It describes how clearly a person can see at a distance compared with standard normal vision.
Why do surgeons use LogMAR instead of Snellen?
LogMAR allows visual acuity to be measured in evenly spaced steps, making it easier to analyse data in research studies and clinical trials. This precision helps surgeons and researchers evaluate treatment outcomes more accurately
What does 0.0 LogMAR mean?
A value of 0.0 LogMAR corresponds to 20/20 vision in the Snellen system. Negative LogMAR values indicate vision better than 20/20, while positive values represent reduced visual acuity.
Why convert between LogMAR and Snellen?
Converting between these two systems helps translate clinical research results into a format that patients and the general public can easily understand. It also helps clinicians interpret visual acuity data from different sources.
Is this visual acuity converter clinically accurate?
This converter provides accurate mathematical conversions based on standard visual acuity relationships. However, clinical visual acuity measurements should always be interpreted alongside professional eye examinations and diagnostic testing.