Cataract extraction and posterior chamber intraocular lens (PC-IOL) implantation were carried out in 21 primary angle glaucoma (POAG) and 26 primary angle closure glaucoma (PACG) eyes in which preoperative intraocular pressure (IOP) was well controlled with medication. The postoperative IOP on the first postoperative day was significantly higher than the preoperative level in POAG eyes, while no significant difference was seen in PACG eyes. The postoperative IOP was significantly lower than the preoperative level at 3 and 6 months postoperatively in POAG eyes and at 1-12 months postoperatively in PACG eyes. Medication did not differ significantly pre- and postoperatively. In 64 +/- 11% (SE) of POAG and 63 +/- 15% of PACG the status of IOP control did not worsen at 2 years. Overall, 70% of the eyes the status of IOP control improved postoperatively, and this was maintained for 2 years in 44 +/- 12%. The present result implies that in primary glaucoma, PC-IOL implantation surgery does not need to be combined with glaucoma surgeries when the IOP was satisfactory controlled and the stage of disease was not advanced.