Abstract: The present invention relates to a protective device for performing work in areas of greatly varying light intensities, comprising a viewing window having a portion provided with a pair of relatively adjustable grid supports with the movement of said supports being adapted to be controlled by electromagnetic means in response to the intensity of light incident on said protective device and/or the type of light, and which allow the affected portion of said viewing window to be darkened (dimmed) or rendered translucent, whereby said grid supports comprise a material being permeable to light in the visible range of spectrum and said darkening portions (the grid strips) comprise a material being highly absorbent to light in the visible range of spectrum.