11. The identification of the theoretical / geometrical horopter with the Vieth-M�ller circle should be reconsidered. 12. Consistently, the shape of the empirical horopter have been found to deviate from the geometrical horopter. 13. Consistently, the shape of the empirical horopter have been found to deviate from the geometrical horopter . 14. All these empirical horopters are in fact corresponding, empirically, to the equal visual direction horopter . 15. The Hering Hillebrand deviation describes the fact that the empirical horopter does not fall on the geometrical horopter. 16. The Hering Hillebrand deviation describes the fact that the empirical horopter does not fall on the geometrical horopter . 17. More recently natural images analyses suggested that the shape of the empirical horopter might match natural images statistics. 18. Following Hering, it is usually meant by empirical horopter the " equal visual direction " horopter. 19. Following Hering, it is usually meant by empirical horopter the " equal visual direction " horopter . 20. Hering went as far as ridiculing Helmholtz's ( unimportant ) mathematical errors in his derivation of the horopter .
