SYSTANE® significantly reduced symptoms of dryness in the morning and evening, compared to Refresh Tears* (p = 0.015 and p = 0.023, respectively) (Figure 1).
Subjects in the group using SYSTANE® also reported lower frequencies of foreign body sensation (Figure 2) and felt their eyes were "refreshed longer" compared to those in the REFRESH TEARS* group (p = 0.033 and p = 0.037 respectively).
The observed efficacy differences could be attributed to the differences in formulations with respect to preservatives, demulcents, viscosity, active ingredients and excipients. SYSTANE® is preserved with POLYQUAD®, while Refresh Tears* is preserved with Purite*. Both preservatives have shown to be safe and have been used in numerous ophthalmic formulations for several years.
The difference in viscosity between the two products may account for some of the observed effects. The viscosities of the solutions are approximately l0 cps and 3 cps for SYSTANE® and Refresh Tears* respectively. A unique attribute of SYSTANE® is the addition of HP-Guar as a gelling agent, which is pH sensitive. When exposed to the ocular pH viscosity increases significantly.
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Back to the Top- Christensen MT, Cohen S, Rinehart J, Akers F, Pemberton B, Bloomenstein M, Lesher M, Kaplan D, Meadows D, Meuse P, Hearn C, Stein JM. Clinical evaluation of an HP-guar gellable lubricant eye drop for the relief of dryness of the eye. Curr Eye Res. 2004. Jan;28(1):55-62.
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