Objective To observe whether pressure boost could induce changes in intracardiac pressures,and also to investigate the mechanism involved.Methods Seventeen healthy volunteers [13 males and 4 females,with an age range of 25.76 ± 5.16 years,and average age of 18-34] were recruited for the study.Without the knowledge of the examiners and examinees about the purpose of the research,they entered the hyperbaric chamber.The examiners detect the intraocular pressures (IOP) of the examinees with the Japanese NIDEK NT-2000 non-contact tonometer under the following conditions:(1) baseline intraocular pressures at rest.(2) during the stay at atmospheric pressure for 30 min without breathing pure oxygen; after breathing pure oxygen for 10 min at atmospheric pressure.(3) compression to a pressure of 60 kPa at a rate of 2.0 kPa/s without breathing pure oxygen; (4) during the stay at the pressure of 60 kPa for 30 min without breathing pure oxygen ; (5) after decompression to 0 kPa pressure,also without breathing pure oxygen.Results Average intraocular pressures measured during their stay at atmospheric pressure for 30 min without breathing pure oxygen,after breathing pure oxygen for 10 min at atmospheric pressure and after decompression to 0 kPa pressure without breathing pure oxygen were (13.57 ±3.04),(13.86 ± 3.16) and (13.33 ± 3.12) mmHg respectively.No statistical significance could be seen in measured data,as compared with that of the baseline intraocular pressures [(13.48 ± 2.87) mmHg] (P ＞ 0.05).Average intraocular pressures measured after they were compressed to 60 kPa without breathing pure oxygen and during their stay at 60 kPa for 30 min without breathing pure oxygen were (16.06 ±2.48) and (15.65 ± 2.54) mmHg respectively,and statistical difference could be seen,when compared with that of the baseline intraocular pressures(P ＞ 0.01).Conclusions When there was a pressure boost,most people would display elevated IOP due to poor response to pressure,only a few people would experience IOP drop also due to poor response to pressure and IOP of still a few people would remain basically unchanged.

Objective To observe whether pressure boost could induce changes in intracardiac pressures,and also to investigate the mechanism involved.Methods Seventeen healthy volunteers [13 males and 4 females,with an age range of 25.76 ± 5.16 years,and average age of 18-34] were recruited for the study.Without the knowledge of the examiners and examinees about the purpose of the research,they entered the hyperbaric chamber.The examiners detect the intraocular pressures (IOP) of the examinees with the Japanese NIDEK NT-2000 non-contact tonometer under the following conditions:(1) baseline intraocular pressures at rest.(2) during the stay at atmospheric pressure for 30 min without breathing pure oxygen; after breathing pure oxygen for 10 min at atmospheric pressure.(3) compression to a pressure of 60 kPa at a rate of 2.0 kPa/s without breathing pure oxygen; (4) during the stay at the pressure of 60 kPa for 30 min without breathing pure oxygen ; (5) after decompression to 0 kPa pressure,also without breathing pure oxygen.Results Average intraocular pressures measured during their stay at atmospheric pressure for 30 min without breathing pure oxygen,after breathing pure oxygen for 10 min at atmospheric pressure and after decompression to 0 kPa pressure without breathing pure oxygen were (13.57 ±3.04),(13.86 ± 3.16) and (13.33 ± 3.12) mmHg respectively.No statistical significance could be seen in measured data,as compared with that of the baseline intraocular pressures [(13.48 ± 2.87) mmHg] (P ＞ 0.05).Average intraocular pressures measured after they were compressed to 60 kPa without breathing pure oxygen and during their stay at 60 kPa for 30 min without breathing pure oxygen were (16.06 ±2.48) and (15.65 ± 2.54) mmHg respectively,and statistical difference could be seen,when compared with that of the baseline intraocular pressures(P ＞ 0.01).Conclusions When there was a pressure boost,most people would display elevated IOP due to poor response to pressure,only a few people would experience IOP drop also due to poor response to pressure and IOP of still a few people would remain basically unchanged.