In Marvel’s Daredevil, Daredevil’s heightened senses follow the childhood accident that left Matt Murdock blind.
As a child, Matt pushed a man out of the path of an oncoming truck and was struck by hazardous chemicals from the vehicle. The accident blinded him, while the chemicals dramatically amplified his hearing, touch, smell, taste, and spatial awareness. The television series presents these abilities as the foundation of his superhero identity.
Matt cannot see in the ordinary sense, but he builds a detailed awareness of his surroundings through sound, vibrations, air movement, and other sensory information. This is often described as a radar-like sense, allowing him to navigate and fight despite his blindness.
A common mix-up is saying that blindness alone gives him superhuman senses. In Daredevil’s fictional origin, blindness is the childhood affliction, while the chemical exposure explains why his remaining senses become extraordinarily powerful.