Noun
The line or surface in which are situated all the points which are seen single while the point of sight, or the adjustment of the eyes, remains unchanged.
Source: Webster's dictionaryBut contrary to Howard, he explained why Ibn al-Haytham did not give the circular figure of the horopter and why, by reasoning experimentally, he was in fact closer to the discovery of Panum's fusional area than that of the Vieth-Müller circle. Source: Internet
D'Aguilon expanded on the horopter by saying in his book: error At first glance, it seems that Aguillon discovered the geometrical horopter more than 200 years before Prevost and Vieth and Muller. Source: Internet
In other words, it describes how only objects on the horopter are seen in their true location. Source: Internet