Abstract
Abstract: :
Purpose: It is not known if yoga is a safe form of exercise for individuals with glaucoma or at risk for glaucoma. Multiple studies have quantified variations in intraocular pressure as influenced by posture. Head–down postures cause an increase in intraocular pressure. In fact, one case report identified the prone position as the culprit in yoga–induced attacks of acute glaucoma. To date, no study has physically quantified the intraocular pressure change over time in complete head–down postures—a position utilized in multiple yoga postures. Methods: The intraocular pressure of twenty–eight eyes of fourteen healthy volunteers were measured in the upright sitting position three times and averaged. The volunteers then performed a supported headstand (complete head–down posture) with measurement of the intraocular pressure at zero seconds and sixty seconds. The volunteers returned to the upright position with repeated measurements at zero seconds and sixty seconds. Results: The mean intraocular pressure of the twenty–eight eyes was 16.4 mm Hg with a standard deviation of 2.04. The intraocular pressure increased significantly to 33.6 mm Hg at time=0 seconds (p=0.015) and 33.0 mm Hg at time=60 seconds (p=0.018) in the complete head down posture. The pressure decreased to 17.7 mm Hg at t=0 seconds and 16.1 mm Hg at time=60 seconds upon returning to the upright position, which was not significantly different from the baseline measurements. Conclusions: Complete head–down yoga postures cause a significant increase in the intraocular pressure which is immediate and does not change significantly over a short period of time. Upon returning to the upright position, the intraocular pressure immediately returns to baseline. These findings suggest that complete head–down yoga postures may pose a risk for patients with glaucoma or glaucoma suspects and should thus be avoided.
Keywords: intraocular pressure