Reading the rows of an eye chart is read as testing how clearly you see. Dream books connect the shrinking letters to details you are straining to make out in waking life.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.