Optical element containing an optical spacer

An optical element containing a rough surface having a roughness average equal to at least 5 micrometers wherein the rough surface contains at least two roughness populations in which the roughness average of the at least two populations varies by at least 8 micrometers, wherein the optical element is a light diffuser wherein at least one of the roughness populations comprises a plurality of randomly distributed complex lenses, where each individual lens overlaps a piece of another lens, forms within another lens, or engulfs another lens, on at least one surface of the film and the randomly distributed complex lenses comprise randomly placed major lenses and randomly placed minor lenses.