I agree with many who say that several of the old spells from Oblivion and Morrowind should be put back into the game, but I believe I've found a decent alternative to the Night Eye spell. You'll need to get 100 in Illusion and speak to the Illusion trainer at the College of Winterhold; he will give you a spell called "Vision of the Tenth Eye". Novice level and costs 0 magicka. While this may be aggitating, just keep casting calm spells on NPCs (even if it is a guard) or muffle on yourself to raise the skill.

Night Eye gives the world a blue tint; Vision of the Tenth Eye makes everything black and white. I just tested it in Blackreach (anyone who has been there knows how dark it is; almost pitch black). This helped quite a bit with navigation by making everything lighter and the black & white made the shadows easier to see. Note I said "decent"; having to grind up to 100 just to see in the dark is a bit of an inconvenience compared to the Apprentice-level Night Eye spell in Oblivion, but it is better than nothing. I know some might have already thought of it, but I just felt like giving a suggestion to help those who miss Night Eye; hope it helps.