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) 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.
picture and letter images:
If you have been given a visual acuity measurement that has a number other than 6 on top of the fraction, click here for information on how to convert this measure.
If you have been given a visual acuity measurement in a different format e.g. 1.0 logMAR or 30 cycles per degree (cpd) click here for information on converting acuities into Snellen fractions.
A variety of picture and letter images are available at each acuity level. The picture images are larger in overall size than the letter images. This is because it is the width of the elements within the picture or letter, rather than the overall size which is important in defining the acuity.