The images in these pages can be used to give an indication of the detail and size of image a child with a given visual acuity should be able to see.
It is tiring and frustrating to work with images that are only ‘just visible’ so we advise that children work with images that are at least twice their visual acuity.
You may have Visual Acuity measures for the right eye and left eye separately (monocular) or together (binocular). Generally it is the eye with the best acuity (smallest number at the bottom of the fraction if written in Snellen convention) or the binocular acuity that should be used to decide on suitable image sizes.
To find out what size of image should be seen easily at different distances click on the visual acuity below which matches or approximates to the one you have been given. Picture and letter images are available. Choose the image that is most appropriate for the individual.
For each acuity level several pages of images are presented. The text at the top of the page details whether these images are the minimum size that is likely to be seen or a size that should be easily seen.
Please click on relative links for the Snellen/logMAR numbers below to obtain Picture and Letter downloads
|Snellen/logMAR Value||Picture Downloads||Letter Downloads|
|Snellen 6/480 or 1.9logMAR||Pictures||Letters|
|Snellen 6/360 or 1.8logMAR||Pictures||Letters|
|Snellen 6/240 or 1.6logMAR||Pictures||Letters|
|Snellen 6/180 or 1.5logMAR||Pictures||Letters|
|Snellen 6/120 or 1.3logMAR||Pictures||Letters|
|Snellen 6/90 or 1.2logMAR||Pictures||Letters|
|Snellen 6/72 or 1.1logMAR||Pictures||Letters|
|Snellen 6/60 or 1.0logMAR||Pictures||Letters|
|Snellen 6/48 or 0.9logMAR||Pictures||Letters|
|Snellen 6/36 or 0.8logMAR||Pictures|
|Snellen 6/24 or 0.6logMAR||Pictures|
|Snellen 6/18 or 0.5logMAR||Pictures||Letters|
|Snellen 6/12 or 0.3logMAR||Pictures|
Sometimes visual acuity is recorded in other notations e.g. logMAR or cycles per degree. These other notations can (with care) be converted to a Snellen fraction for comparison. This web page will deal only with acuities recorded in Snellen fractions.
If acuity has been recorded using logMAR or cycles per degree the tables below can be used to approximate the Snellen fraction. Also available in the tables is a conversion from metric (UK standard) to Imperial (US standard) recording.
NOTE: tests which use logMAR or cycles per degree to record acuity may not be measuring the same type of visual acuity as a Snellen test and conversions must be treated with caution.
|Snellen equivalent||LogMAR||Cycles per degree (cpd)|
Visual acuity is often measured by the Optometrist, Optician or Orthoptist by asking the patient to read progressively smaller letters presented on a wall chart six meters (20 feet) away.