vent 100 according to a preferred embodiment of the present invention the hopper vent 100 includes an exterior frame 110 an interior frame 120 a transparent insert 130 and a screen 140 the hopper vent 100 also includes a window lock 155 and a window spring 150 in the preferred embodiment of fig1 the window lock 115 secures the interior frame 120 to the exterior frame 110 and the window spring 150 aids in the positioning of the interior frame 120 within the exterior frame 110 the exterior frame 110 and interior frame 120 are preferably comprised of four injection molded pieces which may be snapped together to form the exterior frame 110 and the interior frame 120 as shown in fig1 the exterior frame 110 of the hopper vent 100 may be attached to a surrounding glass block window for example the exterior frame 110 encloses and is attached to the interior frame 120 the interior frame encloses and supports the transparent insert 130 the screen 140 is removably fixed to the top and bottom of the exterior frame 110 in a conventional hopper vent light passes only through a transparent window mounted in an opaque frame in the hopper vent 100 of fig1 light passes through the transparent insert 130 but also passes through the exterior frame 110 and interior frame 120 directly because the frames 110 120.