Intraocular Pressure (IOP) Change and Frequency of IOP Spike After Cataract Surgery in Normal-tension Glaucoma: A Case-Control Study.

Purpose: To evaluate the early-postoperative intraocular pressure (IOP) changes and frequency of IOP spike after cataract surgery in normal-tension glaucoma (NTG) eyes and to compare them with those of nonglaucomatous eyes.

Materials And Methods: This was a case-control study. We reviewed the medical records of patients who had undergone cataract surgery. One-to-one (1:1) case matching was performed, each matched set consisting of 1 NTG and 1 nonglaucomatous eye as the control eye. Comparisons between those 2 groups were performed. Specifically, IOP was measured preoperatively and 1 day, 1, 2, and 4 weeks postoperatively. The incidence of IOP spike was evaluated according to the criteria of IOP higher than 21, 25, 30 mm Hg, higher than 5, 10 mm Hg over baseline IOP, and 50% above preoperative IOP.

Results: A total of 298 eyes (149 NTG eyes and 149 control eyes) were enrolled. Preoperative IOP did not show any significant difference between the 2 groups (P=0.687). IOP significantly decreased in both the NTG and control groups [P<0.001, repeated-measures analysis of variance (ANOVA)]. No significant differences in this regard were detected between the 2 groups (P=0.618, repeated-measures ANOVA). When IOP spike was evaluated according to the 6 criteria, the frequencies were <3% at any timepoint. There was no significant difference between the 2 groups.

Conclusions: In both the NTG and control groups, IOP gradually decreased in the early-postoperative period after cataract surgery, and there was no significant difference between the 2 groups. The frequency of IOP spike was <5% in both the NTG group and the control group.