 |
VISION PARAGUAY
A UK REGISTERED CHARITY DEDICATED TO THE RIGHT TO SIGHT IN ALL DEVELOPING COUNTRIES
|
|
|
VISION PARAGUAY
A UK REGISTERED CHARITY DEDICATED TO THE RIGHT TO SIGHT IN ALL DEVELOPING COUNTRIES
|
|
The Problem 1
|
|
What do we mean by blindness?
This is not a trivial question and the impact of reduced vision varies in different countries. In the UK having vision less than 6/12 means you cannot drive but to the World Health Organisation (WHO) this is not even visual impairment. The WHO defines blindness as vision of less than 3/60 (20/400)
What does this mean?
|
 |
Normal vision is 6/6 (20/20)
The first number "6" is the distance at which you read the chart (6 metres). The second number is the distance at which you should be able to read the letter.
So a vision of 6/12 means that reading the chart at 6 metres you can only read the line you should be able to read at 12 metres.
If you convert metres to feet (6 metres = 20 feet) we get the American system
|
 |
Blindness is less than 3/60
If you cannot see the top letter at half the distance, you are
blind according to the WHO definition
|
|
The Problem 1
|
