A funky eye test that rates how good your colour vision is has turned into a viral social network hit for online casino iGame.com.The test displays blocks of different colours with the viewer tasked with identifying which one has a slightly different colour than the rest, all against the clock. It sounds easy but becomes increasingly tricky as the test progresses. Launched last month, it's gone on to become something of a social media phenomenon, reaching up to 2,000 shares per minute on Facebook at one stage.The test, which has been translated in 24 languages, has now been taken by more than 20 million users worldwide. iGame, which is home to a wide selection of slots, video poker, table and casino games is working on a similar test which will test reaction times later this month.“Speed is key to us. Our customers are our most valuable asset and they appreciate when things are fast, so that is what we deliver,” iGame.com Chief Operating Officer Robin Larsson said.“The eye and speed tests are not directly related to our core casino business, but we are always looking at new ways to entertain and engage our customers.“We were absolutely stunned by the reaction to the launch of the eye test, and we are hoping that the speed reaction test also goes viral!”If you haven't taken the test yet, you can do so by visiting iGame Eye Test.