Dynamic Lighting in (vanilla) Minecraft
Ooh, I just thought of something! You could have a torch that, when held, gives you night vision (no blindness though). However, this would mean that everything you can see will be lit up, and this is perhaps not what you intended.
What you could ALSO do is use Cimap's method and make it so that when the end portal block disappears (due to the player being to close to a ceiling) it gives the player night vision to make up for the loss of light. :)