Abstract: Light-transparent lens structures typically formed of conventional synthetic acrylic resins and intended for use as lenses in a lensed fluorescent troffer or similar lighting fixture, the lens structures of the invention are characterized by repeating patterns of conical or pyramidal depressions formed in the lens with upper portions or apices thereof being inverted. The lens structures of the invention preserve the angular relationships of lens material to air interfaces of conventional conical lens patterns, for example, and further preserve angular beam shaping capabilities while substantially reducing the amount of material needed to form the lens structures per se.