Achluophobia

If you have a severe case of achluophobia (fear of the dark), for instance, you may want to wait at the mouth of the cave.

When I was little, I had achluophobia and had to sleep with some kind light, any kind of light.

I'm not exactly sure when I was diagnosed with achluophobia—the fear of darkness—but I've always been afraid to be left alone in the dark.