A specialist tool used in ophthalmic treatments to dilate the lacrimal duct is the Castro Lac Dilator (Double End). It has two different ends, one with a medium-taper tip and the other with a needle-point tip. Both ends are made to fit different patient anatomy and surgical needs. Usually constructed of stainless steel, the instrument is around 140 mm long and has a circular, knurled handle that makes it easy to hold.