Figure 2.

In order to collect human tear samples using the microcapillary flow technique, participants were asked to sit facing forward with their heads tilted all the way to one side to ensure basal tears from the surface of the eye pooled in the lateral canthus (outer corner of the eye). With sterile, gloved hands, glass microcapillary tubes were used to draw tears from the ocular surface. Following sample collection, proteome analysis is typically conducted using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), automated electrophoretic technology (AET) or mass spectrometry techniques (in order of increasing accuracy).