Insto has been my hubby’s family’s favorite for eye care product. His mother, father and one of his brothers all have the same issue: easily get reddish eyes because of irritation. His brother likes to swim, a lot; my hubby works in a factory, where it’s dusty and smoky; his mother and father likes to wake up ‘til midnight and get up in the very early morning (lack of sleep). All of these factors could trigger eye irritation easily. But Insto has done it all. This eye drop is very compact to be carried everywhere. It contains 7.5 ml sterile eye drops. Once they get eye irritation they will use this eye drop. But my mother-in-law told me that people with glaucoma and wearing contact lenses are prohibited to use this product. Now let’s talk about the effect. Since this is a strong eye drop (it says it contains tetrahydrozolin HCL and benzalkonium chloride ~ but I don’t even know what it is), it definitely relieves eye irritation quickly. Wush… it’s like magic: the eye irritation goes away after several blinks! However, this eye drop shouldn’t be used after one month. I don’t know, maybe it’s because it expires quickly once it’s opened. This is a great eye drops, but please read the indications and contra indications first on the leaflet before using, since this is a strong eye drops.