Visual acuity chart

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The cloth chart has a letters chart on one side which includes both Snellen and LogMAR values along the edges.

On the other side is a tumbling E chart (also with Snellen and LogMAR values) which is particularly useful for small children or those who do not use the Roman alphabet in their first language.

The chart is designed for use at a distance of 3 metres from the patient (which can be estimated through 3 large steps or measured with a tape). The chart can be attached to a notice or magnetic board whilst in use.

How to assess visual acuity video

 

Recording visual acuity

Start with the largest letters at the top of the chart working downwards. Stop the test when the patient can no longer correctly identify the letters or indicate the direction of the E’s,

Now record the Acuity achieved – the left side of the chart is labelled in Snellen notation with Logmar on the right

Snellen is recorded as a fraction with a test distance on top (in this case 3 metres) and the last full line seen correctly on the bottom. If some of the next line was also seen then write +1 or +2 for the extra letters seen.

For Logmar – again record the last full line read correctly but this time subtract 0.07 if they managed one extra letter correctly or 0.14 if they saw two additional letters.

For example if the patient read the 4^th line down all correctly (Snellen 7.5, LogMar 0.4) and then two of the letters or E’s in the next line down the visual acuity would be recorded as Snellen 3/7.5+2 or LogMar 0.4-0.14 = 0.26.