Purpose
Elevated intraocular pressure (IOP) is the most common known risk factor for glaucomatous damage. IOP increases on assuming a body position other than the upright one. (1) An increase in IOP is directly related to the inclination of the body toward the complete inverted position.(2) Studies have described an elevated IOP following a headstand posture, particularly in glaucoma patients.(3,4) The purpose of this study is to investigate IOP changes during four common yoga positions (asanas) in glaucoma and healthy participants. As inverted positions are known to increase IOP significantly, specifically the headstand (Sirsasana), common yoga positions have been incompletely investigated.(5)
Methods
10 glaucoma (9 female and 1 male; mean age 62.3+15.59) and 10 healthy control (8 female and 2 male; mean age 36.3+12.82) subjects were included. Adho Mukha Svanasana, Uttanasana, Halasana and Viparita Karani were the four positions tested (Figure 1); in this respective order. IOP was measured prior, immediately at start of position, 2 minutes into position, immediately after assuming sitting position, and 10 minutes later seated for a final IOP. A calibrated Reichert Model 30 Pneumatonometer was used.
Results
Repeated-measures ANOVA revealed a significant IOP increase at each time point for all 4 positions both in glaucomatous and healthy eyes (all P<0.01) (Table 1). Aside from the Halasana position, which reached borderline significance (P=0.08), there was no significant difference between glaucomatous and healthy eyes regarding the IOP response to position changes. However, glaucoma severity - based on the visual field mean deviation- was associated with increased IOP response in all groups (all P<0.05). The Adho Mukha Svanasana position was associated with the highest IOP increase (P<0.01).
Conclusions
Previous studies have only tested the headstand position, as shown; common practiced yoga positions also increase IOP. All four positions show a significant increase in IOP in all subjects. In glaucoma patients, the severity of their disease was in association with their increase in IOP during all four positions. Yoga practitioners should be aware of the significant increase in IOP during these common positions, specifically glaucoma patients with severe disease.
Keywords: 568 intraocular pressure •
464 clinical (human) or epidemiologic studies: risk factor assessment •
466 clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials