How is visual acuity mesured in Europe?!
Question:
How is visual acuity mesured in Europe?
What would 20/400 vision be?
Answers:
20/20 vision is considered "normal"vision within the population. 20/20 vision means that at a distance of 20 feet, you should be able to read the 20 feet line on the Snellen vision testing chart. If you can only see the 40 feet line on the chart which contains larger size letters or numbers, and which normal people can see when standing 40 feet away, your vision is 20/40 ie below average. In other words the upper figure 20 is the distance you are form the chart, and the lower figure 40 is the lowest line you can read.
Similarly the 200 feet line on the chart is very large print, and normally sighted people can see it up to 200 feet away, but if you can only see it when close up at 20 feet, your vision is reduced to 20/200 in that eye. In other words 20 is the distance your are standing from the chart, and 200 is the lowest line you can read on the chart.
In Israel and many European countries metric measurements are used. Normal vision is considered 6/6, ie from a distance of 6 meters, normally sighted people can see the 6 meter line. 6/12 is equivalent to 20/40, 6/60 to 20/200 etc.