Surgery was performed on nine eyes of nine consecutive patients with chronic postoperative hypotony after prior vitreous surgery for retinal detachment and proliferative vitreoretinopathy. The operation included lysis of adhesions between the iris and the ciliary processes and removal of lens remnants and other fibrocellular tissue covering and/or causing traction on the pars plicata. The preoperative intraocular pressure was less than or equal to 5 mm Hg in all eyes, and the final postoperative intraocular pressure was 8 to 20 mm Hg in five eyes, 6 mm Hg in one eye, 4 mm Hg in one eye, and 0 mm Hg in two eyes. Minimum postoperative follow-up was 7 months and average follow-up was 10 months. This form of surgery to uncover and minimize traction on the ciliary body substantially increased the intraocular pressure in most of the treated cases and suggests that iridociliary adhesions and tissue proliferation covering and/or causing traction on the ciliary processes account for chronic postoperative hypotony in some cases after extensive surgery for proliferative vitreoretinopathy.