People with the condition, known medically as "alexia without agraphia," can write and understand the spoken word but are unable to read, they said.
A stroke brought on word blindness suddenly for a 40-year-old kindergarten teacher and reading specialist, who re-learned to read by teaching herself a new technique, the researchers said.
When shown a word, she looks at the first letter, which she can clearly see but cannot recognize. Beginning with the letter A, she traces each letter of the alphabet over the unknown letter until she gets a match.
For example, when shown the word "mother," she will trace the letters until she comes to M and finds a match. Three letters later, she guesses correctly the word is Mother.
The patient came up with the new technique after some traditional methods, such as phonics, sight words, flash cards and writing exercises, failed, the researchers said.
"To see this curious adaption in practice is to witness the very unique and focal nature" of the deficit, the authors wrote in the journal Neurology.