It is possible that chronic endogenous elevation of cortisol levels secondary to psychological stress may cause permanent damage to the trabecular meshwork, since stress events may aggravate increased resistance to aqueous humor drainage through the trabecular meshwork and/or Schlemm’s canal, which can imbalance trabecular meshwork activity, alter extracellular matrix metabolism and cytoskeleton organization and induce gene expression and cell function changes. Photo: Getty Images.

Experiencing tension is inevitable and part of everyone’s daily life. However, what may be transitory for most people may result in greater consequences for glaucoma patients, even if the stressor is acute.

A new study appearing in Ophthalmology Glaucoma had researchers measuring intraocular pressure (IOP) behavior in primary open-angle glaucoma (POAG) patients after using a standardized protocol to induce psychological stress. Included was a total of 39 POAG patients, 18 of which were subjected to the Trier Social Stress Test (TSST)—a simulated job interview followed by mental arithmetic—and 21 controls. As well, all participants were subject to a modified diurnal tension curve one to four weeks before randomization, where IOP was measured three times between 8am and 2pm.

The researchers found no significant differences at baseline between the groups in age, sex, salivary cortisol or mean diurnal test curve IOP for either right or left eyes. However, there was a difference in mean IOP increase when comparing measurements obtained during the diurnal test curve and immediately after TSST. This was true for both right and left eyes, with increases of 3.8mm Hg and 4.1mm Hg, respectively. Rates of salivary cortisol, salivary amylase, mean arterial pressure and heart rate also increased after the TSST. What’s more, 61.1% (11 out of 18) of patients undergoing the stress test experienced an IOP increase greater than 4mm Hg following the test.

Because of this marked difference, the investigators “believe that repetitive stress stimuli in POAG may compromise IOP control and potentially increase the risk of disease progression.” Their discussion further elaborates on their findings.

It should be noted that this effect occurs in healthy individuals as well, as one previous study noted mean IOP increase of 1.0mm Hg in the right eye and 1.1mm Hg in the left eye after submitting to the TSST.

The authors further elaborate that the post-stress IOP elevation was not only statistically significant but also clinically relevant, being around 4.0mm Hg; many population-based studies have previously documented high IOP levels to be a risk factor in glaucoma progression.

On the other side of this trial, some investigations have been done measuring IOP behavior after anti-stress therapies. One of these studies evaluated effects of mindfulness-based stress reduction on IOP and stress biomarkers in a randomized trial with 90 glaucoma patients. After being assigned either to 21 days of a mindfulness meditation group or control group, results indicated mean IOP reductions from 18.8mm Hg to 12mm Hg in the right eye and 19.0mm Hg to 13.1mm Hg in the left eye of the meditation group. A similar study found a meditation group to express upregulation of nitric oxide synthetase and neuroprotective genes and downregulation of proinflammatory genes.

Taken together, as the authors explain, these correlations “in conjunction with our results, emphasize the correlation between IOP and stress: not only psychological stress can elevate IOP, but anti-stress therapies may improve IOP control.”