What is 20/20 vision?
You hear the expression all the time:
‘20/20 vision’. Someone will flippantly remark, ‘Oh, I have 20/20
vision’ in an attempt to convince you that they have perfect vision. But
what does 20/20 vision actually mean?
If you have 20/20 vision,
it doesn’t mean that you have perfect vision—in fact 20/10 vision is
better—and there are numerous other aspects of good eyesight.
20/20
vision is a measurement of how ‘sharp’ your vision is (also known as
your visual acuity). In particular, 20/20 vision means that you have
sharp vision (can see clearly) at 20 feet from an eye test chart. So the
expression ‘20/20 vision’ isn’t particularly relevant in Australia and
other countries that use the metric system. We should, instead, be
saying ‘I’ve got 6/6 vision!’ But that doesn’t quite have the same ring
to it, does it?
In fact, rather than being perfect, 20/20 is
simply considered ‘normal’ vision. It is the benchmark that scientists
decided was normal so they could test and compare eyesight.
What does 20/40 vision and 20/60 vision mean? 
If
you don’t have clear vision at 20 feet (6 metres) away, you’ll be
assigned a different eyesight ranking, such as 20/30, 20/40, up to
20/200 (6/60 metres), which is considered legally blind in Australia.
20/40
vision means that you have to stand closer to an image to see it
clearly than people with 20/20 vision. To be precise, you can only begin
to see the image clearly at 20 feet away (6 metres), whereas people
with ‘normal’ eyesight can see the image clearly as far back as 40 feet
(12 metres).
The same concept applies to 20/60 (6/18) vision (and
all other measurements up to 20/200). You have to stand at 20 feet (6
metres) away from an image to see it clearly, when a person with normal
vision can see the same image even when they are standing 60 feet (18
metres) away.
What does 20/10 vision mean?
Here’s a fun
party trick: if someone tries to impress you by saying they’ve got 20/20
vision, smile and tell them that you’ve got 20/10 vision! Yes, as it
turns out, there are better eyesight sharpness ratings than 20/20.
20/10
vision (6/3 vision in Australia) means that you can see an image
clearly at 20 feet away (6 metres), when people with normal eyesight
have to stand 10 feet (3 metres away) to see it clearly.
What other factors contribute to good eyesight?
Although
sharpness is very important, you shouldn’t get too caught up with it
being the be-all-and-end-all in terms of good eyesight.
Other factors that contribute to good eyesight include:
- peripheral vision
- the ability to see and distinguish colors
- depth perception
Contact lenses for vision correction
If you are unsure about the sharpness of your vision, you should book in to get an eye test with an optometrist.
And if it turns out you don’t have perfect vision, you’ll become part of the rather large club of people who don’t.
To treat vision problems, you basically have 3 choices:
- glasses
- contact lenses
- refractive eye surgery
Obviously
most people opt for either contact lenses or glasses, or both, with
surgery being a last resort. Contact lenses are actually a very
practical way of correcting your vision, allowing you to do things like:
- keep your same ‘look’ (some people don’t like the way they look with glasses)
- participate in sports and outdoor activities freely
Why choose contact lenses?
Read our blog posts on contact lenses to find out more about why they are an ideal choice for most people:
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