Randomized Trial of Early Phacoemulsification versus Peripheral Iridotomy to Prevent Intraocular Pressure Rise after Acute Primary Angle Closure

Purpose: To compare the efficacy of early phacoemulsification versus laser peripheral iridotomy (LPI) in the prevention of intraocular pressure (IOP) rise in patients after acute primary angle closure (APAC). Design: Prospective randomized controlled trial. Participants: Sixty-two eyes of 62 Chinese subjects, with 31 eyes in each arm. Methods: Subjects were randomized to receive either early phacoemulsification or LPI after aborting APAC by medications. Patients were followed up on day 1; week 1; and months 1, 3, 6, 12, and 18. Predictors for IOP rise were studied. Main Outcome Measures: Prevalence of IOP rise above 21 mmHg (primary) and number of glaucoma medications, IOP, and Shaffer gonioscopy grading (secondary). Results: Prevalences of IOP rise for the LPI group were 16.1 %, 32.3%, 41.9%, and 46.7% for the follow-ups at 3, 6, 12, and 18 months, respectively. There was only one eye (3.2%) in the phacoemulsification group that had IOP rise at all follow-up time points (P<0.0001). Treatment by LPI was associated with significantly increased hazard of IOP rise (hazard ratio [HR], 14.9; 95% confidence interval [Cl], 1.9-114.2; P = 0.009). In addition, a maximum IOP at presentation > 55 mmHg was associated with IOP rise (HR, 4.1; 95% Cl, 1.3-13.0; P = 0.017). At 18 months, the mean number of medications required to maintain IOP < 21 mmHg was significantly higher in the LPI group (0.90±1.14) than in the phacoemulsification group (0.03±0.18, P<0.0001). Mean IOP for phacoemulsification group (12.6±1.9 mmHg) was consistently lower than that of the LPI group (15.0±3.4 mmHg, P = 0.009). Mean Shaffer grading for the phacoemulsification group (2.10±0.76) was consistently greater than that of the LPI group (0.73±0.64, P<0.0001). Conclusion: Early phacoemulsification appeared to be more effective in preventing IOP rise than LPI in patients after abortion of APAC. High presenting IOP of >55 mmHg is an added risk factor for subsequent IOP rise. For patients with coexisting cataract and presenting IOP of >55 mmHg, early phacoemulsification can be considered as a definitive treatment to prevent IOP rise.