Figure 7 of Azartash, Mol Vis 2011; 17:756-767.

Figure 7. This plot represents the changes in tear film thickness by subject as a function of time upon instillation of Refresh Liquigel (Allergan, Irvine, CA). These data were used to calculate the mean retention of effect time for the sample, 32 min, to become statistically indistinguishable from the mean baseline tear thickness.