Analytic expression for the horizontal horopter–revisited

In this brief note, we reanalyze the analytic expression for the horizontal horopter. We ask the fundamental question if the analytic plot is the best way to describe horopter data. We have analyzed the formalism and give an expression for the empirical horopter in terms of a new equation. This expression will also give us the curvature of the horopter. The derivation of this expression is given in the paper.