目的：探讨初诊未行治疗的原发性开角型青光眼(primary open angle glaucoma，POAG)患者习惯性体位眼压及眼灌注压(ocular perfusion pressure，OPP)波动趋势，并验证由日间平均坐位及卧位眼压推导夜间峰值眼压的可行性。

方法：选取POAG患者19例19眼及正常对照组18例18眼，分别于10：00，14：00，18：00及22：00时行坐位眼压及血压监测，为验证由日间卧位眼压推导夜间峰值眼压的可行性，另对POAG组于卧位5min后再行监测。2：00，5：00及7：00行卧位监测，计算出OPP并行数据分析。由已知公式通过日间眼压计算夜间峰值眼压，并与实际值对比。

结果：24h习惯性体位下，POAG患者平均眼压及眼压波动均高于正常对照组(P<0.05)，POAG组平均眼压峰值出现于凌晨5：00，对照组则为7：00。两组夜间眼压均值均大于日间，差异有统计学意义(P<0.05)。两组内习惯性体位平均眼灌注压(MOPP)均表现为夜间低于日间(P<0.05)，而两组间MOPP无明显统计学差异(P>0.05)。POAG患者MOPP波动较对照组大，差异有统计学意义(P<0.05)。由两公式推导所得夜间眼压峰值均与所测值无明显统计学差异(P>0.05)。

结论：习惯性体位下POAG组及正常人的眼压峰值多出现在凌晨至上午，POAG患者的习惯性体位平均眼压及眼压波动均高于对照组。两组内夜间灌注压均较日间低，且POAG患者有更大的MOPP波动。由日间眼压推导夜间峰值眼压具有一定的可行性。

AIM:To characterize the circadian fluctuation of intraocular pressure(IOP)and ocular perfusion pressure(OPP)at habitual position in newly diagnosed patients with untreated primary open angle glaucoma(POAG)and to test the feasibility of calculating nocturnal peak IOP from the diurnal mean IOP.

METHODS:Nineteen patients(19 eyes)with POAG and eighteen healthy controls(18 eyes)were included and underwent 24-hour monitoring of IOP and blood pressure. At 10:00, 14:00, 18:00 and 22:00 o'clock in the daytime, all the subjects were monitored in sitting position while at 02:00, 05:00 and 07:00 o'clock at night in supine position. For testing the feasibility of calculating nocturnal peak IOP from mean IOP in diurnal supine, all patients still needed to be monitored for IOP in supine position after lying for 5min in the daytime. Measurements were taken in diurnal supine at 2:00, 5:00 and 7:00. OPP was calculated and analyzed. Nocturnal peak IOP was calculated with known formulas and compared with the actual values.

RESULTS:The mean IOP and the fluctuation of IOP of POAG group were higher than those of healthy group in 24-hour habitual position(P<0.05). The mean peak IOP appeared at 05:00 o'clock in POAG patients while at 07:00 o'clock in healthy controls. Both groups had higher mean nocturnal IOP than diurnal(P<0.05). In both groups, the nocturnal mean ocular perfusion pressure(MOPP)was lower than diurnal(P<0.05). However, there was no obvious difference between two groups on MOPP(P>0.05). POAG group had higher fluctuation of MOPP than that of healthy group(P<0.05). Besides, there was no difference between actual peak IOP and values calculated from formulas(P>0.05).

CONCLUSION:The peak IOP of habitual position in patients with POAG and healthy people appears in the morning, and POAG group has higher mean IOP and fluctuation of IOP. Nocturnal OPP is lower than diurnal OPP in both groups, and POAG group has larger fluctuation of MOPP. It might be feasible that we could calculate nocturnal peak IOP from the diurnal mean IOP.