Nasolacrimal drainage system obstruction after orbital decompression.

We reviewed 123 cases of orbital decompression in 63 patients with dysthyroid ophthalmopathy. Of 90 cases of transantral ethmoidal orbital decompression, 14 (16%) resulted in epiphora. The tearing began between 11 and 18 months after surgery. All patients had obstruction distal to the common internal punctum. The delayed onset suggested progressive cicatricial obstruction of the nasolacrimal drainage system. Damage to adjacent tissues probably caused scarring to extend into the system.