Stephen Lang wore contact lenses that greatly restricted his vision, particularly in low light. The other actors, in the scene taking place in the dark, wore lenses that made them look like they had dilated pupils but also greatly restricted their vision.
In contrast to his previous work on Evil Dead (2013), director Fede Alvarez decided this movie would have less blood, an original storyline, more suspense, and no dependence on spooky supernatural elements - which he felt was currently overused.
Ironically, the street where the blind man lives is called "Buena Vista," which is translated to mean "Good View" in Spanish.
The combination to the Blind Man's safe, 2978, is actually director Fede Alvarez's birthday - Feb. 9, 1978