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Distance Vision Test
This
test, also known as the Visual Acuity Test, tests the sharpness
of vision by grading the ability of the eye to discern diminishing
sizes of alphabets, numbers or shapes at a specified distance
of 6 metres.
Instructions :
- Stand at a distance of 3 metres or 10 feet from the monitor
and read down to the smallest row of numbers that you can
see.
- Test one
eye at a time, first without your glasses and then with. Keep
your other eye covered using an eye patch. To make a simple
eye patch, just fold a piece of tissue and tape it over your
eye.
- Your visual
acuity is given by the fraction (i.e. 6/60, 6/36, 6/24, 6/18,
6/12, 6/9, 6/6 or 6/5) designated to the smallest row of numbers
you can read correctly.
- First
test your right eye, then your left eye. Record your visual
acuity without (unaided visual acuity) and with your glasses
(aided visual acuity)
Interpreting
The Results
Normal good visual acuity is 6/6. If your visual acuity is
worse than 6/6, move on to the next test, the Pin Hole Test.
The Pin Hole Test will determine whether you need to wear
corrective glasses to see better.
More
Information On The Distance Vision Test
- Visual acuity results
are designated by fractions e.g. 6/60, 6/30, 6/24, 6/18, 6/12,
6/9, 6/6, 6/5. What do these fractions mean?
- When we
say that an eye has 6/24 visual acuity, we mean to say that
the smallest row of letters the tested eye can discern at
a distance of 6 metres is what a normal eye can discern at
a greater distance of 24 metres. From this, we can see that
the numerator 6 is a constant. The denominator varies and
a number greater than 6 would represent less than normal visual
acuity. The larger the denominator number, the poorer is the
vision.
- 6/6 visual
acuity is normal vision. 6/5 represents the fortunate 10 percent
of the population that has better than normal vision.
- The legal
visual requirement to obtain a driving license is 6/12 in
most countries. A person seeing worse than 6/60 despite best
spectacle correction is considered to be legally blind. About
10 percent of people are fortunate to have better than 6/6
vision, that is 6/5.
- The test
is ideally done at 6 metres because light rays from objects
seen at 6 metres and beyond reaches the eye as parallel rays
and in the NORMAL EYE are focused precisely onto the central
macula region of the retina without the need for any focusing
effort.
- In some
countries, normal visual acuity is designated as 20/20 which
simply is the same measurement designated in feet. In other
countries, the fraction is converted to a decimal figure but
they mean the same thing
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