Window-Eyes boasts 100% text accuracy 100% of the time thanks to the use of the Microsoft Word DOM. The DOM (or Document Object Model) allows Window-Eyes to communicate directly with the document. It is through this convention that Window-Eyes can guarantee that the text you hear when using your arrow keys, or any of the new navigation keys, is exactly the same, visible text that exists in your document. Window-Eyes can also achieve this same accuracy when reading selected text. Note that Window-Eyes still uses the screen to gather text information when you use the Window-Eyes mouse keys (by design to replicate the visual layout of the screen), but with the new Word features available, using the mouse should not be necessary. Although Window-Eyes communicates directly with the document for text accuracy, it is possible for windows to sit on top of the text, causing Word itself to miss-report document information. This is a caveat of using the Microsoft Word DOM.