What Is Mirror Writing?

Mirror writing is a form of reversal. It means that the person is writing backward, from right to left, the letters or words appearing like ordinary writing seen in a mirror.

While mirror writing is considered to be normal during the preschool phase, it should alert parents and teachers if it continues after formal reading and writing instruction has begun. If it continues it indicates a severe visual perceptual deficit, especially with visual discrimination of position in space. More specifically, the person is unable to discriminate between left and right, has a problem with the reading direction, and might also be unable to cross the midline. Deficits in other foundational skills might contribute to this problem.

Leonardo da Vinci (1452-1519), Italian Renaissance painter, most popularly known for his fresco The Last Supper and his painting Mona Lisa, was also a sculptor, engineer, architect, inventor, scientist and naturalist. And he is the most celebrated mirror writer to date. He usually used mirror writing, starting at the right side of the page and moving to the left. Only when he was writing something intended for other people did he write in the normal direction.

No one knows the true reason Leonardo used mirror writing, though several possibilities have been suggested:

• He was trying to make it harder for people to read his notes and steal his ideas.
• He was hiding his scientific ideas from the powerful Roman Catholic Church, whose teachings sometimes disagreed with what Leonardo observed.
• Writing left handed from left to right was messy because the ink just put down would smear as his hand moved across it. Leonardo chose to write in reverse because it prevented smudging.