Respiratory Muscle Training and Intraocular Pressure: A Prospective Study in Individuals With Normal and High-Normal Intraocular Pressure.

PRCIS: Expiratory resistance training with the AiroFit PRO device causes a dose-dependent, temporary increase in intraocular pressure (IOP) of about 3 mm Hg, with individuals with high-normal IOP reaching values that approach clinically concerning thresholds at maximum resistance.

PURPOSE: To examine the acute effects of graded expiratory resistance using the AiroFit PRO breathing trainer on intraocular pressure (IOP) in healthy individuals with normal and high-normal IOP, and to evaluate the agreement between noncontact and applanation tonometry during respiratory strain.

METHODS

This prospective study included 60 healthy participants (120 eyes): 40 with normal IOP (group 1) and 20 with high-normal IOP (group 2). IOP was measured at baseline and during expiratory efforts at 6 progressively increasing resistance levels (10-200 cmH 2 O/(L/s)) using both noncontact tonometry (NCT) and Goldmann applanation tonometry (GAT). Statistical analyses included the Friedman test for repeated measures, correlation analysis, and multiple linear regressions.

RESULTS

IOP demonstrated a significant progressive increase across all resistance levels (Friedman χ 2 (6)=442.86, P <0.001). The mean IOP increased from 16.57±4.22 mm Hg at baseline to 19.58±4.20 mm Hg at maximum resistance, representing a mean increase of 3.01 mm Hg (18.2%). The magnitude of IOP change did not differ significantly between the normal and high-normal IOP groups (Cohen d=0.055). Baseline IOP was a strong predictor of Level 6 IOP ( R2 =0.845). The NCT and GAT results showed excellent agreement ( r =0.870-0.929) between the 2 methods.

CONCLUSIONS

Respiratory training with the AiroFit device results in dose-dependent increases in IOP. While the relative magnitude of IOP change is similar regardless of baseline IOP status, individuals with high-normal IOP reach absolute values approaching clinically concerning thresholds. These findings have implications for glaucoma risk counseling among users of respiratory training devices.