Intraocular Pressure Changes Following Three "Head below the Heart" Postures in Yoga Practitioners - A Prospective Observational Study.

Context: Intraocular pressure (IOP) increases during "sirasasana" and may be a risk factor for the progression of glaucoma. Other "head below heart" asanas may also cause increase in IOP.

Aims: To determine the change in IOP following three "head below the heart" postures-"meruasana", "viparithakarni," and "sarvangasana".

Settings and design: Prospective observational study conducted in a tertiary care hospital over 3 weeks.

Materials and methods: Willing, regular yoga practitioners recruited by purposive sampling performed "meruasana", "viparithakarni," and "sarvangasana" in random order according to a 3 × 3 periods cross over study design after baseline measurement of IOP, blood pressure (BP), and pulse rate. Each asana was held for 30 s. Within 15-30 s of completion of asana, IOP, BP, and pulse rate were recorded. There was an interval of 30 min between the asanas.

Statistical analysis used: Normality of data was tested using the Kolmogorov-Smirnov test. Repeated measures of ANOVA with Tukey-Kramer multiple comparisons was used to compare changes in IOP, BP, pulse rate following asana. P ≤ 0.05 was accepted as statistically significant.

Results: There were 33 participants with a mean age of 29.6 ± 10.5 years (95% confidence interval [CI]: 26.02, 33.18). The mean baseline IOP was 15.5 ± 3.4 mm Hg (95% CI: 14.34, 16.66) in the right eye and 16.7 ± 3.4 mm Hg (95% CI: 15.54, 17.86) in the left eye. IOP showed a significant reduction following each of the three asanas (P < 0.0001). However, neither pulse rate (P = 0.53) nor BP (P = 0.27) showed any change following the asanas.

Conclusions: "Meruasana," "viparithakarni," and "sarvangasana" when held for 30 s by healthy yoga practitioners resulted in post-asana drop in IOP with no significant change in pulse rate or BP.