THC:YAG nasolacrimal duct recanalization.

In an early exploration of a new technique for creating a patent nasolacrimal duct system, a chromium-sensitized and thulium- and holmium-doped YAG laser was used to canalize the nasolacrimal duct of a fresh-frozen bisected human cadaver head. The laser--long-pulsed (300 milliseconds), compact, self-contained, and solid-state--operates in the near infrared range (2.1 microns). The technique involved passing a 550-micrometer quartz fiberoptic through the dilated superior punctum and canalicular system, down through the nasolacrimal duct. The quartz fiberoptic was then withdrawn into the area of the lacrimal sac. Pulse energies of 500 mJ were used at a repetition rate of five pulses per second to ablate the duct lining. The nasolacrimal duct was then unroofed and the epithelial lining of the duct histopathologically evaluated.