“It is a remarkable piece of bio-electric engineering…” Geordi La Forge
The VISOR (an acronym for Visual Instrument and Sensory Organ Replacement) was a medical prosthetic used by the Federation to aid with blindness and visual impairment. It gave users visual acuity far beyond typical human ability, into other spectrums including infrared and ultraviolet.
The VISOR, as seen in the Star Trek: The Next Generation TV series and the 1994 film, Star Trek: Generations, was worn by Helmsman and subsequently Chief Engineer Geordi La Forge, played by Levar Burton. Multiple props were produced, with various revisions and changes made to the design over its long tenure. There was no single definitive VISOR prop.