The process of formation of Marx line is studied in this paper. Various theories have been proposed previously in order to explain the mechanisms which lead to the development of Marx line. These theories are based on the characteristics of stained area and do not pay attention to the behavior of dye solution itself on the surface. The aim of this paper is to investigate the latter behavior and introduce a new theory based on it, in order to explain the process of the Marx line formation.This study also introduces “Coffee Ring Effect” and its possible applications in explaining some ophthalmological phenomena.

Evaporation pattern of Rose Bengal, Fluorescein, Methylene Blue and Trypan Blue were analyzed on different surfaces. Additionally, The effect of dye solution’s behavior on the beneath surface is adopted in order to propose the theory. This new hypothesis is called “Anionic Dye Deposition”. The proposed theory is based on “Coffee Ring Effect” phenomenon.

During the evaporation process of dye solutions, it was observed that almost all of the solute was deposited at the edge of the drop on hydrophilic surfaces. Furthermore, in the study of lid margin staining, it is observed that tear meniscus alteration during gaze affects staining pattern. This observation invalidates former hypotheses which only focus on stained surface characteristics.

Ophthalmic dyes represent the characteristics that are expected from “Coffee Ring Effect” phenomenon during evaporation. According to these findings, the authors believe that these characteristics can be applied to explain lid margin staining. The proposed theory, successfully explains the experiments’ outcomes. It is proposed that Marx line formation is due to dye deposition at this line.