A diffuser for a lighting device comprises a diffuser region, a hook element and a nose element. A light fixture comprises a housing with an opening and a diffuser as described above, in which the nose element extends through the opening, optionally further comprising an accessory including at least one spring element engaging the hook element. A light fixture structure comprises a housing defining an opening and an first attachment element comprising a nose element, a hook element and a connection region, and optionally further comprising a diffuser engaging a first portion of the hook element, and/or an accessory which engages a second portion of the hook element. An eyeball accessory comprises first and second housing elements pivotably attached to each other. An accessory for a light fixture comprises a housing member and a spring element engageable with a fixture.