AIM: To observe the pathological changes of the lower segment of nasolacrimal duct mucosa in rabbits at different stages after retrograde lachrymal dilated drainage tube implantation.

METHODS: Totally 14 New Zealand rabbits were used in the present study. One side of nasolacrimal duct was obstructed to produce an experimental model and operated the reverse implantation of nasolacrimal duct intubation. Histological changes of the lower segment of nasolacrimal duct mucosa were observed by routine light microscope at 2, 4, 6, 8, 10, 12 and 14wk after the operation.

RESULTS: Compared with the control side, the group of 2 and 4wk after surgery presented the inflammatory cytokine. The group of 12wk after the operation presented isolated granuloma. Group 12 and 14wk presented scattered granuloma. The size of the granulomas was smaller and the density of epithelioid cell and fibroblast were lower in group 12wk than those in group 14wk by HE and Masson trichrome stain.

CONCLUSION: Recurrent Silicone Tube is used to treat nasolacrymal duct obstruction. Nasolacrimal duct can be narrowed and blocked again by granuloma, progressive fibrosis and adhesion of surrounding tissues when tube is in the duct more than 12wk.