Many children reverse “b’s” and “d’s”, some even confuse them with “p’s” and “q’s”. Most parents find this very concerning and believe it is indicative a vision problem. Actually, it has to do with the law of form constancy and it is normal to have difficulty remembering the direction of letters until around 3rd grade.
Look at the following series of photos, there is a hand in each image. In each case the hand has been flipped or turned. But they are all hands. The law of form constancy states that it doesn’t matter how something is turned or flipped it is still the same thing. This law helps us relate to the world around us
Now consider “b”, “d”, “p”, “q”, they are all made up of a ball attached to a stick. If you look at them in the following series and compare them to the hand above you quickly realize they are all a ball with a stick attached which have been turned or flipped. This is the first time in life where the law of form constancy does not hold. All of a sudden when something is turned or flipped it has changed and has a new meaning.
Many children struggle with this concept and generally it is not related to vision. There may be a vision problem relating to reversals if when you can show a child a “b” and they are unable to pick out the matching letter among a “b”, “d”, “p”, “q” . In those cases often times there is an alignment or clarity issue causing difficulties in correctly visualizing the letter. But simply reversing letters is not indicative of a vision problem.