Boots WebMD Partners in Health
Return To Boots

Eye health centre

Select a topic to explore more.
Select An Article

Visual acuity and 6/6 vision

Visual acuity is a measure of your central vision, the ability to distinguish details and shapes of objects.

Distant vision is tested with a chart with differently sized letters read from a distance of six metres away. This is called the Snellen’s Test Types.

Someone who can read the second line of letters up from the bottom is said to have 6/6 vision. This used to be called 20/20 vision when the test was done from 20 feet away before metric measures took over.

6/6 does not translate into perfect vision and does not indicate other important aspects of sight such as peripheral vision, the ability to identify colours or depth perception.

Having 6/12 vision means you can see at six metres what a person with normal vision can see at 12 metres away.

Each eye is tested separately - and an overall score is given for both eyes or binocular vision. So a person's Snellen test scores might be:

Left eye

Right eye

Binocular vision








No vision


For driving, the Department of Work and Pensions says a person needs to be able to read the third line up from the bottom - or 6/9 vision. This can be with normal eyesight, or corrected with glasses or contact lenses.

Near vision is tested in a different way by looking at a test card with sentences of different font sizes.

Each paragraph is defined with 'points' to measure the print. A point is 1/72 of an inch. In most tests, N48 is the biggest type with N5 the smallest. The chart is read at a comfortable reading distance of about 35cm (14 inches) from the eyes.

Eye tests are important

To maintain good eye health and vision, it is important to have your eyes tested every two years, or more frequently if advised. You should seek advice immediately if you have any sudden loss of vision, eye pain, inflammation or irritation. Most eye diseases can be identified during a routine eye test and treated when detected at an early stage. If you have health problems, such as diabetes, you may need to visit your optometrist more frequently to detect any complications.

What options are available to correct impaired vision?

There are many safe and affordable options for those in need of vision correction. They include:

  • Glasses. Perhaps the most traditional form of vision correction, glasses improve vision by bending light. They are practical, affordable and safe.
  • Contact lenses. Contact lenses are often chosen for cosmetic reasons or by people with an active lifestyle. There are many different types, colours and materials, so it is best to seek advice and shop around to find the contact lenses that work best for you.
  • Corrective surgery. Vision correction surgery improves sight by changing the refractive, or light bending, properties of the eye. Refractive surgery restores a person's ability to see at a moderate visual acuity, meaning that there may still be a need in some cases for glasses or contact lenses.
Next Article:

WebMD Medical Reference

Stay informed

Sign up for BootsWebMD's free newsletters.
Sign Up Now!

Popular slideshows & tools on BootsWebMD

agave syrup
These may not be so healthy
exercise illustration
The 7-minute workout
female patient consulting with female GP
How to boost your chances
bowl of soup
Small changes that lead to weight loss
heart rate graphic
What is it, and how is it treated?
smiling woman
Much more than weight loss
crossword puzzle
Tips for the first hard days
sperm and egg
Facts to help you get pregnant
Put your best face forward
sick child
Treating your child's cold & fever
couple makigh salad
How it can help with weight loss
couple watching sunset
How much do you know?