An optical element for uniformly dispersing light from a plurality of linearly aligned LEDs includes a body made of a transparent polymeric material, in which the body has a longitudinally extending center portion having a transverse cross-sectional profile that is uniform along the length of the optical element, and legs extending away from opposite sides of the center portion and extending downwardly to define a recess. The center portion has a top surface and a bottom surface that together define a longitudinally extending lens portion that collects light from the LEDs and refracts the light to produce a desired beam pattern. Uniformly and closely spaced apart transverse grooves can be provided on the top surface of the longitudinally extending lens portion to uniformly spread light on an illuminated surface and eliminate the appearance of dark and light areas on the lens portion when it is illuminated by the LEDs.