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Tuesday, January 06, 2009

The WHO Definition of Low Vision Visual acuity 6/60 to 6/18 in the better eye with best correction.

Question 47
The WHO Definition of Low Vision
a. Visual acuity 6/60 to 3/60 in the better eye with best correction.
b. Visual acuity 6/60 to 6/18 in the better eye with best correction.
c. Visual acuity 6/18 to 3/60 in the better eye with best correction.
d. Visual acuity <3/60 in the better eye with available correction.
Answer
b. Visual acuity 6/60 to 6/18 in the better eye with best correction.
Reference:
Renu Jogi 3rd edition Page 441
Quality
Reader
Status
Repeat
QTDF
Journals
Discussion
Definition Low Vision given by WHO is
Ä     Visual Acuity in the better eye with best correction is less is 6/18 and equal or more than 6/60
Explanation
Self Explanatory
Comments
Categories of Visual impairment (WHO)
Categories
Visual Acuity with best correction (better eye)
Maximum vision (less than)
Minimal vision (equal to or more than)
Normal
6/18 on Snellen Chart
Low Vision
1
Low Vision
6/18 on Snellen Chart
6/60 on Snellen Chart
2
Economic Blindness
6/60 on Snellen Chart
3/60 on Snellen Chart
Blindness
3
Social Blindness
3/60 (finger counting at 3 metres)  or visual field constricted to less than 10o
1/60 (finger counting at 1 metre)
4
Manifest Blindness
1/60 (finger counting at 1 metre) or visual field constricted to less than 5o
PL (light perception)
5
Absolute Blindness
No Light Perception (No PL)
Tips
Visual Impairment disability categories basedon its severity and proposed disability percentage (Government of India)
Categories
All with best correction
Percentage impairment
Better eye
Worse eye
Category 0
6/9 -6/18
6/24 – 6/36
20 %
Category I
6/18-6/36
6/60 to Nil
40 %
Category II
6/60-4/60
or
Field of Vision 10o to 20o
3/60 to nil
75 %
Category III
3/60 to 1/60
or
Field of Vision less than 10o
Finger counting at 1 feet to nil
100 %
Category IV
Counting fingers a 1 feet to nil
or
Field of Vision less than 10o
Counting fingers a 1 feet to nil
or
Field of Vision less than 10o
100 %
One eyed person
6/6
FC at 1 ft to Nil
30 %

1 comment:

  1. Knowing these and taking into consideration the data of visual impairment disability could gauge the ratio of people separated into categories of varying visual acuity.

    ReplyDelete

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