You should remove the eyeliner before going to bed. Because you will not know what will you do when you are sleeping with the eyeliner on your eyes. Maybe you can have a sound sleep with the eyeliner, but do you know that maybe you will rub your eyes during sleeping, which means you will let the eyeliner into your eyes and then your eyes are easily get infected. In addition, you know the makeup often clogs pores and adds some chemicals on your skin, which will make your skins around your eyeshadow age faster and faster. I think you do not want to get the result. If you are really tired, you can prepare some makeup remover wipes, such as the Garnier brand, and then you can clean off the eyeliner with it quickly. Hope my suggestions help you.