Mesoamerican Long Count calendar 20, 2012 (Gregorian Calendar), followed by the start of the 14th b'ak'tun, 13.0.0.0.0, on December 21, 2012. There are only two references to the current creation's 13th b'ak'tun in the fragmentary Mayan corpus: Tortuguero Monument 6, part of a ruler's inscription and the recently discovered La Corona Hieroglyphic Stairway 2, Block V. Maya inscriptions occasionally reference future predicted events or commemorations that would occur on dates that lie beyond 2012 (that is, beyond the completion of the 13th "b'ak'tun" of the current era). Most of these are in the form of "distance dates" where some Long Count date is given,
Fixation disparity Fixation disparity Fixation disparity exists when there is a small misalignment of the eyes when viewing with binocular vision. The misaligment may be vertical, horizontal or both. The misalignment (a few minutes of arc) is much smaller than that of strabismus, which prevents binocular vision, although it may reduce a patient's level of stereopsis. A patient may or may not have fixation disparity and a patient may have a different fixation disparity at distance than near. There are several methods to quantify fixation disparity. The Mallett card, the Bernell lantern slide, the Wesson Card and the Disparometer may be used.