SNELLEN OPTOMETRIC CHART, working distance 6.1m, 23 x 35.5cm

An ophthalmic chart imprinted with block letters (optotypes) and/or other symbols (e.g., LEA symbols for children who can not read) in gradually decreasing sizes, identified according to distances at which they are ordinarily visible (normally 6 metres or 20 feet); used in testing visual acuity. This device is typically designed in black upon white printed material that is mounted on a wall of the optician/doctor's examination room/office.

Snellen chart

There are several rows of ototypes (standardized symbols used for vision test) on an eye chart. The ototypes can vary as letters, geometric symbols, or numbers. In most cases, eye chart with letters (aka Snellen chart) is used.

Different types of eye charts

• TUMBLING E eye chart. The Tumbling E eye chart can detect nearsightedness in young children who don't yet know all letters of the alphabet and of children or adults who cannot communicate verbally due to a physical or mental disability, language barrier or other reasons.
• EMEQVIAC1E- - TUMBLING E EYE CHART, 4 meter distance, 23 x 35.5cm
• EMEQVIAC2E-: VISUAL ACUITY CHART, ATMAIGNAC type, working distance 5m
• CHART with SYMBOLS / PICTURES
• EMEQVIACPS- - PARINAUD OPTOMETRIC CHART, hand-held, short distance (Pictures on one side, symbols (E and C) on the other side) (see picture)
• CHART with LETTERS. The first chart developped for eye testing was the Monoyer chart (By taking the first letter of each line from the last line, the word obtained is MONOYER, then by taking the last letter of each line always from the penultimate line, the word obtained is FERDINAND, both its first name and last name)
• MONOYER EYE CHART: EMEQVIACMY50: to be used at a distance of 5m
• SNELLEN OPTOMETRIC CHART. In a standard Snellen chart, there are eleven lines of block letters.
• EMEQVIACS61: working distance 6.1m, size of the chart = 23 x 35.5cm
• LogMAR CHART. the improved version of the Snellen chart: LogMAR chart.
• view.distance 2.5m: EMEQVIACL251 & EMEQVIACL252-,
• view.distance 4.0m: EMEQVIACL401 & EMEQVIACL402
• MODIFIED ETDRS. Modified ETDRS: a revised set of ETDRS charts was proposed, aiming to minimize the differences in relative difficulty between lines on the charts. A limitation of the original ETDRS charts is that they do not allow for European-wide implementation, since they contain letters from the Latin (Roman) alphabet, which are not readable by all European citizens.
• EMEQVIACM401 & EMEQVIACM402: view distance 4m

• Test the visual acuity with correction (e.g. glasses)
• Test one eye at a time. Start with the right eye, covering the left one without pressing on it. Then, examine the left eye by doing the opposite. If the child is using correction glasses, you can cover the eye with a sheet of paper.

Calculate the distance at which the child must stand facing it, using the following formula: measure the height of the letter E (first line, 20/200) in millimeters. Then, divide the value of this measurement by 88. Finally, multiply it by 6. The result shows the distance at which the child must be placed, in meters.

During the visual acuity test, the patient is required to sit at a standardized distance away from the chart. The patient is then required to identify the letters. Generally, the patient is required to start reading the larger letters and then gradually move on to smaller ones.

As such, there may come a moment when the patient is unable to identify the progressively smaller alphabets. The smallest alphabet that the patient can identify marks his/her visual acuity.

The Tumbling E eye chart can detect nearsightedness in young children who don't yet know all letters of the alphabet. It's also a good “game” to play with a child who might be apprehensive about his or her first eye examination.

Tumbling E eye charts also are useful to test the distance visual acuity of children or adults who cannot communicate verbally due to a physical or mental disability, language barrier or other reasons.