As described in the Quartermaster Supply Catalog, Section I, page 27:
A goggle provided with slits in top and bottom of eye cup to reduce fogging and equipped with ground and polished glass lenses, green tinted to filter out ultra-violet, infra-red and excessive light rays, for use on snow surfaces to prevent snow blindness.
Grommet vented canvas dark brown velvet rims, metal mesh vented return panels, leather and elastic adjustable straps, leather nose bridge.