Correlation between Intraocular Pressure Fluctuation with Postural Change and Postoperative Intraocular Pressure in Relation to the Time Course after Trabeculectomy

Abstract

Background. To investigate the correlation between intraocular pressure (IOP) fluctuation with postural change and IOP in relation to the time course after trabeculectomy. Methods. A total of 29 patients who had previously undergone primary trabeculectomy with mitomycin C were examined. IOP was obtained at 1, 2, 3, 6, and 12 months and then every 6 months postoperatively. Results. The postural IOP difference before surgery was 3.0 ± 1.8 mmHg, which was reduced to 0.9 ± 1.1 mmHg at 1 month, 1.0 ± 1.0 mmHg at 2 months, 1.3 ± 2.0 mmHg at 3 months, 1.3 ± 1.4 mmHg at 6 months, 1.4 ± 1.5 mmHg at 12 months, and 1.1 ± 0.7 mmHg at 18 months after trabeculectomy (P < 0.01 each visit). The filtering surgery failed in 7 out of 29 eyes. Postural IOP changes were less than 3 mmHg in those patients who did not require needle revision at every visit. However, in patients who did require needle revision, the increase in the posture-induced IOP was greater than 3 mmHg prior to the increase in the sitting position IOP. Conclusions. Assessment of postural IOP changes after trabeculectomy might be potentially useful for predicting IOP changes after trabeculectomy.

Figure 1

Comparative IOP using Goldmann applanation tonometer and ICare for seated patients. Correlation coefficient = 0.86. Regression equation Y = 0.91x + 3.96.

Figure 2

Posture-induced intraocular pressure (IOP) changes measured with an ICare rebound tonometer before and after trabeculectomy over an 18-month period. The IOPs in both the sitting and the lateral decubitus positions were decreased at every visit after the trabeculectomy (P < 0.01 every visit; Bonferroni test). The IOP in the lateral decubitus position was significantly increased (P < 0.05; paired t-test). The squares, upper bars, and lower bars indicate 25–75%, 95%, and 5% percentiles, respectively.