Changes in Intraocular Pressure and Anterior Chamber Parameters Following Cataract Surgery, Vitrectomy, and Combined Surgery.

Purpose: The aim of this study is to investigate changes in intraocular pressure (IOP) and anterior-segment parameters before and after cataract surgery, vitrectomy, and combined surgery.

Methods: The records of patients who had undergone cataract surgery (cataract group), vitrectomy (vitrectomy group), or combined cataract surgery and vitrectomy (combined group) at our hospital were retrospectively examined. The vitrectomy group consisted of pseudophakic eyes. IOP and anterior-segment measurements, including anterior chamber depth (ACD), angle opening distance (AOD), trabecular-iris angle (TIA), and trabecular-iris space area (TISA), were measured using swept-source anterior-segment optical coherence tomography before and 6 months after surgery in 41, 15, and 40 eyes, respectively.

Results: In the cataract and combined groups, there was a decrease in IOP (cataract group: from 15.8 to 13.4 mmHg, p <0.001; combined group: from 15.8 to 14.2 mmHg, p = 0.002) and an increase in the central corneal thickness after surgery (p <0.001). The ACD increased in all groups, with a smaller increase in the vitrectomy group (p <0.03). Postoperative AOD, TIA, and TISA were significantly increased in the cataract and combined groups (p <0.02). Higher preoperative IOP and larger IOP reduction after surgery were correlated with smaller preoperative AOD, TISA, and TIA in cataract and combined groups (p <0.034). A small preoperative ACD was related to smaller preoperative AOD, TISA, TIA (r > 0.649, p <0.001), and postoperative IOP reduction in the cataract and combined groups (r = 0.377, p = 0.018 and r = 0.559, p = 0.001, respectively).

Conclusions: Compared to the vitrectomy group, the cataract and combined groups showed reduced postoperative IOP and increased AOD, TISA, and TIA. In these two groups, patients with shallower preoperative ACDs showed greater changes in IOP after surgery. Changes in IOP after surgery are thought to be related to changes in the anterior segment caused by the removal of the crystalline lens.