A Snellen test uses a chart with different sizes of letters or forms to evaluate your visual acuity-that is, the sharpness of your vision. The test shows how accurately you can see from a distance
The level of vision is usually measured using a Snellen chart or equivalent. It is viewed at 6 metres (20 feet). A visual acuity of 6/6 indicates that the chart was viewed at 6 metres, and the lowest line that could be read was labelled 6.
The UK driving standard falls somewhere between the 6/12 and 6/9 on the chart. ‘Unaided visual acuity' refers to the vision without glasses, ‘best corrected visual acuity' (BCVA) to the vision with glasses.
"Normal" vision is equivalent to 6/6, but many people who are well corrected by their spectacles are often able to see even better, perhaps 6/5 or 6/4.
|
