Eye test charts

Eye health workers can use a variety of tests to check people’s eyesight. Find out about common eye test charts and why they’re used.

A boy sits in a chair wearing optometry glasses during an eye test. A man's hand places a lens into the right side of the pair of glasses.

When people have their eyes tested, they will often be shown a chart containing rows of letters in various sizes. One of the most common tests used by optometrists is the Snellen chart.

Named after the Dutch ophthalmologist Herman Snellen, who designed it in 1862, it’s used by many eye care professionals worldwide to assess people’s eyesight.

Before the 1860s, ophthalmologists used a variety of eye test charts, which meant a patient’s results could vary between doctors. Snellen’s chart helped to standardise testing, making it easier to diagnose vision problems and produce spectacles.

Today, optometrists still use a variety of charts, however the units used to measure a person’s vision mean that their results are consistent and comparable regardless of the test or clinician.

Read on to learn more about some of the most common eye tests you might encounter during your next visit to the optician.

Did you know?

Refractive errors are the leading cause of visual impairment.

A woman holds a small child, who is wrapped in a blanket. The woman is looking at an eye test chart on a wall in a hospital.

The Snellen and LogMAR charts

A standard Snellen chart has 11 rows of block letters, which decrease in size from top to bottom. In 1976, two researchers in Australia created the LogMAR chart to improve the standardisation and accuracy of the Snellen chart.

During an eye test, a person is asked to cover one eye and read out letters on the chart from a distance of about 6 metres.

Both tests measure the ability to see clearly at a set distance, which is known as visual acuity. The person is asked to read the letters on the lowest line they can comfortably see.

‘Standard’ visual acuity is often called 20/20 vision. This means you can clearly read at a distance of 20 feet (6 metres) what a person with ‘average’ eyesight is expected to see at that distance.

An optometrist can use a person’s visual acuity to check if they have a vision problem, such as near-sightedness (myopia) or long-sightedness (hyperopia).

While the Snellen and LogMAR charts are most common, eye health workers can use other charts to measure someone’s visual acuity, depending on their age, language or disability.

Did you know?

Refractive errors affect 161 million people worldwide.

A female eye doctor points to a letter on a chart during an eye test.

The Tumbling E chart

The Tumbling E chart, also created by Dr Snellen, only uses the letter E, which is shown in different positions and sizes. This means it can be used with non-English speakers, people who can’t read and children.

During an eye test, the person is asked to say which direction the letter E is facing, such as left, right, up or down. If someone is deaf or non-verbal, they can point in the corresponding direction.

Did you know?

More than 85% of people with a visual impairment live in low and middle income countries.

An eye health worker holds a chart with symbols on during a girl's eye test.

The Lea test chart

The Lea symbols test, created by the Finnish ophthalmologist Dr Lea Hyvärinen, can be used with young children. Instead of letters, the chart has symbols, such as an apple and square.

Other variations of this test, such as the Kay picture test, use familiar images, such as animals or common objects.

Did you know?

3.5 million people are blind because of refractive errors.

A woman wearing optical glasses reads from a hand-held chart during an eye test.

The near vision chart

A near vision test, such as a Jaegar eye chart, is used to check someone’s near visual acuity. It has a short paragraphs of text in various font sizes, which is held at reading distance.

The person is asked to read the text at different sizes to assess their near vision. This helps to detect long-sightedness (hypermetropia) and age-related vision changes (such as presbyopia).

Did you know?

Colour blindness affects around 1 in 12 men and 1 in 200 women.

An Ishihara colour blindness test, showing green dots with the number 8 picked out in shaded red dots.

The Ishihara test

While not usually part of a standard eye test, an Ishihara test can diagnose colour blindness. Developed by Japanese ophthalmologist Dr Shinobu Ishihara, it is often used with children to assess if they can see red and green.

During the test, the child is shown a series of coloured circles comprised of dots and asked to identify the coloured number or pattern in the centre of each circle.

Did you know?

510 million people have a near vision impairment that could be addressed with a pair of glasses.

$A female student wears eye test glasses during a refractive error examination.$

Most people who have visited an optician will have used one of these eye test charts. But not everyone has access to basic eye care, such as a simple vision test.

Worldwide, 1.1 billion people have a visual impairment that could be treated or prevented. The main cause of this? Unequal access to eye care services.

At Sightsavers, we believe nobody should be blind from avoidable causes. We’re helping to improve global eye health by treating eye conditions, training healthcare staff and improving health services. But we can’t do this without your support.

Without urgent action, the number of people with preventable visual impairments could rise from 1.1 billion today to 1.8 billion by 2050. Will you help us ensure this doesn’t become a reality?

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