Anterior chamber paracentesis and pH values in patients with acute primary angle closure

To assess the efficacy and safety of anterior chamber paracentesis (ACP) and the changes in pH values in eyes with acute primary angle closure (APAC). This retrospective case-control study involved 22 patients with APAC who underwent ACP (study group) and 21 patients with APAC who did not undergo ACP (control group). Intraocular pressure (IOP) and visual acuity were measured before treatment and 15 min and 24 h after treatment in both groups. The pH of aqueous humor was measured immediately after ACP in the study group. A total of 43 eyes in 43 patients were reviewed. The IOP 15 min after ACP (23.3 +/- 9.6 mmHg) and 24 h after ACP (21.6 +/- 12.0 mmHg) were significantly lower than that before ACP (58.6 +/- 12.9 mmHg). The IOP 15 min after ACP was significantly lower than the IOP 15 min after conventional treatment (55.4 +/- 10.3 mmHg). Visual acuity recovery was achieved earlier after ACP than after conventional treatment. Hyphema after ACP was noted in one eye. The mean pH of the aqueous humor in APAC was 6.99 +/- 0.35. The pH of the aqueous humor significantly correlated with the duration of acute IOP elevation and the IOP before ACP. ACP is an effective and safe procedure. The pH of aqueous humor is lower in eyes with APAC of longer duration and in eyes with higher IOP at presentation.