Excuses at bedtime

The girls have been having a particularly hard time going to sleep lately. They also have a hard time staying asleep which makes for long interrupted nights for us. Most of the time they like to have the light on until they fall asleep, but since Jake left they aren't falling asleep as quickly and end up just playing in their room. So, I give them a few minutes and if they are playing I turn the light off. Though this usually prompts massive fits, Lyla has been crying that she is scared of the dark. I feel like it is just another excuse to get out of bed or to get her way, but she also could be genuinely scared. I am not sure how to address it, but I don't want the "I'm scared" excuse to be abused as another ploy to get her way.