A protective headgear comprising: an automatic darkening filter that comprises a curved switchable shutter that exhibits a curvature; a front cover plate that exhibits a curvature and that is positioned in front of the shutter; and, a rear cover plate that exhibits a curvature and that is positioned in rear of the shutter, wherein the front and rear cover plates and the shutter define an optical path that electromagnetic radiation can follow to reach the eyes of a wearer of the protective headgear; wherein the optical path comprises at least two antireflective layers,,,,, each antireflective layer being disposed on a major front surface or major rear surface of the rear cover plate, a major front surface or major rear surface of the front cover plate, or a major front surface or major rear surface of the curved switchable shutter, wherein the optical path comprises at least one antireflective layer,, that is on a major front surface or a major rear surface of the front cover plate and at least one antireflective layer, that is on a major front surface or a major rear surface of the rear cover plate, and wherein the optical path includes a front air gap of from about 0.5 mm to about 4 mm between a major rear surface of the front cover plate and a maj or front surface of the curved, switchable shutter, and further includes a rear air gap of from about 0.5 mm to about 4 mm between a major rear surface of the curved, switchable shutter and a major front surface of the rear cover plate. an automatic darkening filter that comprises a curved switchable shutter that exhibits a curvature; a front cover plate that exhibits a curvature and that is positioned in front of the shutter; and, a rear cover plate that exhibits a curvature and that is positioned in rear of the shutter, wherein the front and rear cover plates and the shutter define an optical path that electromagnetic radiation can follow to reach the eyes of a wearer of the protective headgear; wherein the optical path comprises at least two antireflective layers,,,,, each antireflective layer being disposed on a major front surface or major rear surface of the rear cover plate, a major front surface or major rear surface of the front cover plate, or a major front surface or major rear surface of the curved switchable shutter, wherein the optical path comprises at least one antireflective layer,, that is on a major front surface or a major rear surface of the front cover plate and at least one antireflective layer, that is on a major front surface or a major rear surface of the rear cover plate, and wherein the optical path includes a front air gap of from about 0.5 mm to about 4 mm between a major rear surface of the front cover plate and a maj or front surface of the curved, switchable shutter, and further includes a rear air gap of from about 0.5 mm to about 4 mm between a major rear surface of the curved, switchable shutter and a major front surface of the rear cover plate. wherein the front and rear cover plates and the shutter define an optical path that electromagnetic radiation can follow to reach the eyes of a wearer of the protective headgear; wherein the optical path comprises at least two antireflective layers,,,,, each antireflective layer being disposed on a major front surface or major rear surface of the rear cover plate, a major front surface or major rear surface of the front cover plate, or a major front surface or major rear surface of the curved switchable shutter, wherein the optical path comprises at least one antireflective layer,, that is on a major front surface or a major rear surface of the front cover plate and at least one antireflective layer, that is on a major front surface or a major rear surface of the rear cover plate, and wherein the optical path includes a front air gap of from about 0.5 mm to about 4 mm between a major rear surface of the front cover plate and a maj or front surface of the curved, switchable shutter, and further includes a rear air gap of from about 0.5 mm to about 4 mm between a major rear surface of the curved, switchable shutter and a major front surface of the rear cover plate.