It took me a while to figure out what it was that was wierding me out about this picture and the other like it, but I then realized that it's the way eyelashes are drawn on both characters.
Usually they are just vague, black lines, sparsely placed to more suggest eyelashes.
The effect, especially in combination with Sakuya's hair color, is at the very least striking, although I don't know if I like it.