Will coloring my contacts myself have any negative effects to health?!

I heard you can color normal contacts by adding coloring drops into the case with the solution and contacts and let it sit over night!. Then in the morning put the contacts in normal and you'll have a ring of color around your eyes!. It works, I have seen it!. What I'm wondering is if it has negative effects or if its same to put it in your eye!?Www@Answer-Health@Com

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