I remember staying up really late when I was young (mid to late 90's) and watching a TV series with short horror stories. The stories weren't connected into a single story, at least as far as I can remember, but were just individual horror stories. I will explain the story that I can remember the most detail about to help narrow it down.
The story starts with a young man that just got a job as a caretaker for an old man that lives alone in a mansion. The old man has a rule that the house must be lit all the time and there can never be any darkness. The caretaker just thinks the old man is paranoid and doesn't take the rule seriously. One night he forgets to keep the room lit that the old man is in and finds him dead in the morning. The rest of the story is foggy until the ending, as he somehow became the new owner of the mansion and I am not sure how that happened. It ends with the young man setting up a trap to kill the darkness. He systematically shut the lights off in the house so that the darkness comes into his room. He also had set up birds in cages so he could track which direction the darkness was coming from, as the darkness would kill the birds as it passes. Once the darkness gets to his door, he shuts off the lights in his room, and blasts the darkness with a giant spotlight once it gets near him. He fails to kill it, and although the darkness didn't kill him, since he had spotlight, he is now blind. At the very end, he is yelling at a caretaker for himself (since he is blind and cant care for himself) and telling him there can never be and darkness in the house and it must be lit all the time, the same as the old man in the beginning.