Liu Hong, Fan Shan, Gulati Vikas, Camras Lucinda J, Zhan Guilin, Ghate Deepta, Camras Carl B, Toris Carol B
Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, NE 68198-5840, USA.
Arch Ophthalmol. 2011 Mar;129(3):269-75. doi: 10.1001/archophthalmol.2011.4.
To investigate the daytime vs nighttime differences in intraocular pressure (IOP), aqueous humor dynamics, central cornea thickness, and blood pressure among a cohort of healthy volunteers.
Thirty healthy volunteers (mean [SD] age, 57.0 [8.6] years) were enrolled in the study. Individuals underwent 1 daytime visit and 1 nighttime visit for the measurement of aqueous humor dynamics. Measurements included IOP by pneumatonometry, aqueous flow by fluorophotometry, outflow facility by fluorophotometry and tonography, uveoscleral outflow by mathematical calculation, central cornea thickness by pachymetry, and blood pressure by sphygmomanometry. Results between visits were compared by appropriate t test. Dependence of the pneumatonometer probe results on position was tested in enucleated rabbit eyes at set pressures and probe positions.
Compared with daytime seated IOP, nighttime seated IOP was reduced by 16%, whereas nighttime supine IOP was increased by 17% (P < .001 for both). The IOP changes were independent of the pneumatonometer probe position. Central cornea thickness was increased at nighttime from a mean (SD) of 560 (37) μm to a mean (SD) of 574 (37) μm (P < .001). Compared with daytime aqueous flow, nighttime aqueous flow was reduced by 49% (P < .001). During the night, fluorophotometric outflow facility was reduced by 45% (P = .05), and tonographic outflow facility was reduced by 17% (P < .01). Uveoscleral outflow at night was decreased when calculated using tonographic outflow facility but not fluorophotometric outflow facility in the Goldmann equation. All other measurements were unchanged.
Significant changes in aqueous humor dynamics at night in healthy mature humans include reductions in aqueous flow, outflow facility, and possibly uveoscleral outflow. Nocturnal changes in IOP are independent of the pneumatonometer probe position and are dependent on an individual's posture during the measurement.
调查一组健康志愿者在白天和夜间眼压、房水动力学、中央角膜厚度及血压的差异。
30名健康志愿者（平均[标准差]年龄，57.0[8.6]岁）纳入本研究。受试者分别在白天和夜间各进行1次访视，以测量房水动力学。测量项目包括：用眼压计测量眼压、用荧光光度法测量房水流量、用荧光光度法和眼压描记法测量房水流出率、通过数学计算得出葡萄膜巩膜流出量、用角膜测厚仪测量中央角膜厚度、用血压计测量血压。访视间的结果采用适当的t检验进行比较。在设定压力和探头位置下，对摘除眼球的兔眼测试眼压计探头结果对位置的依赖性。
与白天坐位眼压相比，夜间坐位眼压降低了16%，而夜间仰卧位眼压升高了17%（两者P均<.001）。眼压变化与眼压计探头位置无关。夜间中央角膜厚度从平均（标准差）560（37）μm增加到平均（标准差）574（37）μm（P<.001）。与白天房水流量相比，夜间房水流量减少了49%（P<.001）。夜间，荧光光度法测量的房水流出率降低了45%（P=.05），眼压描记法测量的房水流出率降低了17%（P<.01）。当用眼压描记法测量的房水流出率而非戈德曼方程中的荧光光度法测量的房水流出率计算时，夜间葡萄膜巩膜流出量减少。所有其他测量值均无变化。
健康成年人夜间房水动力学有显著变化，包括房水流量、房水流出率降低，葡萄膜巩膜流出量可能也减少。夜间眼压变化与眼压计探头位置无关，且取决于测量时个体的姿势。
