An LED-based lighting unit (10) with substantially sealed LEDS (30) is disclosed. The LED-based lighting unit (10) includes a plurality of LEDs (30)coupled to a mounting surface, a plurality of optical pieces (52) each placeable adjacent the mounting surface about at least one of the LEDs (30), and an elastomeric layer (60) abutting and extending between the optical pieces (52). Optionally, an adhesive layer (40) may be interposed between the mounting surface and the optical pieces (52) and/or the elastomeric layer (60). Optionally, a rigid layer (70) may be provided atop the elastomeric layer (60).