What's the side effects for using "redness relief" eye drops? I wear colored contact lens everyday and my eyes becomes very red and there are many red blood silk...I bought a "redness relief" eye drops. When I use it, the red blood silk disappear for a wh

First . First you need your eye doctor to see why you are getting red--is it the lens fit, allergies, or dryness? Treating the correct issue will solve the problem rather than hiding it with get the red out drops which simply cause rebound redness a few hours after use.
"Redness . "redness relief" class of eye drops often has vaso-constricting compounds that gives the appearance of whiter eye. This only last for couple hours than the vessels re-dilate (often more than before) and the redness returns (often worse than before). These products are not recommended by eye doctors. Redness of the eye with contact lenses can be a cause for concern. You should be evaluated by an eye doctor with your contact lenses.
The . The problem with drops that "get the red out" is that they work by constricting the blood vessels on the surface of the eye. The additionally reduce the amount of blood flow to the tear glands. In common cases of redness of the eye, dryness is the problem. The best treatment is with a tear or lubricating drop which will actually moisturize the eye in contract to the drop that you are using which dries out the eye. I additionally caution you to be extremely careful when you have redness when wearing contact lenses as that can be a sign of a very serious problem. The eyes do need to breath and tears will help that process, "redness relief drops" will make your eyes worse. It is probably a good ideas to see an ophthalmologist if your eyes are red later today to make sure that there is nothing serious.