Impact on ocular surface evaporation of an artificial tear solution containing hydroxypropyl guar.
Eye Contact Lens. 2008 Nov;34(6):331-4.
Uchiyama E, Di Pascuale MA, Butovich IA, McCulley JP.
OBJECTIVE: To determine whether any acute effects on evaporative parameters are produced when using a solution containing Hydroxypropyl (HP) (Systane) versus normal saline solution in the eyes of patients with Keratoconjunctivis Sicca at 30 and 60 minutes postinstillation.
METHODS: Randomized double-blinded placebo-control 2-period cross-over clinical trial. Twelve patients with a clinical diagnosis of Keratoconjunctivis Sicca were enrolled in this study. Aqueous tear evaporation was measured at baseline, i.e., before the application of drops on the eye, and at 30 and 60 minutes after instillation of one 40 microL drop of either the HP-Guar containing drop or normal saline on two separate days. Statistical analysis included descriptive data analysis and paired t test.
RESULTS: Hydroxypropyl-Guar resulted in a decrease in aqueous tear evaporation at 30 minutes postinstillation under 25% to 35% relative humidity (RH) (13.2% reduction, P=0.044) and 35% to 45% RH (10% reduction, P=0.028) conditions. The effect of HP-Guar at 60 minutes postinstillation also decreased aqueous tear evaporation but to a lesser degree. Normal saline solution produced no statistically significant increases and decreases of evaporation.
CONCLUSIONS: Aqueous tear evaporation contributes significantly to aqueous tear loss and is humidity dependent. An HP-guar containing solution decreased aqueous tear evaporation 30 and 60 minutes after application. The use of topical medication with known antievaporative effect may be beneficial in dry eye therapy. This effect may also be achieved in normal eyes or sub-clinical dry eyes when in low RH environments.
3 comments:
I just bought some Systane gel drops for moderate to severe dry eye yesterday. I have used them three times and they make my eyes hurt even worse than they do when dry.
I just bought some Systane Ultra Lubicant Drops today also, and looking at the Active Ingrediants, I see Polyethelene Glycol 400 .04% and Propylene Glycol 0.3%. None of the Systane Products on the shelf were different than the drop I chose. Which Systane Drops use hydroxypropyl guar as the active ingredient? How do get the "REAL" Systane?
Kenneth
Ken, it's listed in the INACTIVE ingredients. (This is fairly common with over-the-counter eye lubricants... long story behind that.)
See http://www.drugs.com/pdr/systane-lubricant-eye-drops.html and look at the inactives and you'll see the hydroxypropyl guar.
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