The tear film plays a crucial role in the areas of contact lens wear and dry eye. However, despite its accessibility, there is no “gold-standard” test for assessing its functional quality. Current clinical tests are often poorly correlated with each other and may be subjective and/or invasive in nature. While much effort has been expended in assessing tear volume and stability, significantly less attention has been paid to the mechanism of tear film formation. Early work using motion-photography of naturally occurring lipid particles within the tear film noted that, immediately following a blink, the tears spread upwards over the cornea with a velocity of about 10 mm/sec. More recent work analysing tear spreading in relation to the thickness of the tear film proposed that the key factors influencing spreading were eyelid velocity, tear meniscus, tear viscosity, and surface tension.