What does 20/20 vision mean?

the pupil and iris of the eye

How good is your vision? Is it 20/40? 20/30?

Or maybe you’re one of the lucky ones and it’s 20/16?

Well, if we go by the statistical average, you have 20/20 vision.

But in reality, it’s more likely you have no idea, and you’re thinking what on earth do all these numbers even mean?

This is because unless you’re an optometrist, you won’t be overly familiar with the Snellen chart. We’ll fill you in with exactly what you need to know by first diving into the most well-known standard of vision: 20/20.

Understanding 20/20 vision and the Snellen Chart

In the short video above, expert laser eye surgeon Mr Glenn Carp explains what 20/20 vision means and how it differs from 6/6 vision.

20/20 vision as is the terminology in the US, also known as 6/6 vision here in the UK, is the standard of visual acuity that the majority of people can expect to achieve or even surpass following Laser Eye Surgery.

As suggested, the phrase comes from the Snellen chart — the most common test which optometrists use to determine your visual acuity (the clarity of sharpness of your vision). Using the chart optometrists can generate a general assessment of your quality of vision. They do this by sitting you down opposite the familiar black symbols at a distance of twenty feet or six metres (depending on your preferred unit of measure) and asking you to read down the ever shrinking lines.

As the distance for the Snellen chart is twenty feet, this is why your personalised measurement is always preceded by a ’20’. This unit gives eye doctors a standardised guideline to work with and helps them compare vision across masses of people.

You have 20/20 vision if the smallest line of symbols you can read on the eye chart is the one marked ‘normal’ acuity. This is the standard that an average person can see at twenty feet.

If your vision isn’t good enough to read this line well enough and, for example, the optometrist says you have 20/100 vision, your vision is sub-standard and you can only see at twenty feet what a person with normal vision can see at one hundred feet.

Your chances of being able to see 20/20, however, does depend on your original prescription. For instance, if you have a very high-profile prescription, it may be more difficult for you to achieve this outcome.

As the results of clinics differ, the best way to find out your chances of achieving 20/20 is by checking their published results. You can do this for London Vision Clinic by visiting our results page. By doing this you can also discover your chances of surpassing 20/20 vision and achieving the coveted 20/16 — a gift that leading Laser Eye Surgery clinics regularly offer their patients.

If you’d like to book a consultation with us or find out more about our results, leave us a comment or give us a call us on 020 7224 1005.