Influence of mental stress on intraocular pressure and visual field testing: is there a white coat syndrome in glaucoma?

Purpose To investigate the effects of mental stress stimulus on intraocular pressure (IOP) measurement and visual field (VF) testing. Methods Patients with open angle glaucoma underwent a baseline IOP measurement and VF testing. Afterwards, they completed a computerized mental stress test (Stroop test) which is a known standardized method to induce mental stress. After test completion, patients underwent a second IOP measurement and VF testing. Results Seventy-two eyes of 36 patients were enrolled. Mean age was 67.0 +/- 9.5 years (range 47-84 years). The mean baseline IOP was 15.0 mmHg, and after the Stroop mental stress test, IOP increased to 16.0 mm Hg (P < 0.001). There was a trend towards significant mean deviation decreased from -6.9 dB to -8.0 dB (P = 0.054, t-test) following the stress test. This difference became significant using the Wilcoxon nonparametric test (P = 0.008). Correlation was found between glaucoma severity and change in IOP (P = 0.02) and PSD (P < 0.01). Conclusions We found a small but statistically significant increase in IOP and a trend towards deterioration of visual field mean deviation, following a short mental stress test. Patients with more severe glaucoma showed more pronounced changes. Our results suggest that mental stress could affect IOP measurement in the clinic.