Chiquet Christophe, Custaud Marc-Antoine, Le Traon Anne Pavy, Millet Catherine, Gharib Claude, Denis Philippe
Department of Ophthalmology, Edouard Herriot Hospital, Claude-Bernard Lyon 1 University, Lyon, France.
J Glaucoma. 2003 Jun;12(3):204-8. doi: 10.1097/00061198-200306000-00004.
To determine the change in intraocular pressure (IOP) due to postural changes in young healthy volunteers.
Intraocular pressure was measured using a calibrated Pulsair noncontact tonometer in both eyes of 25 female volunteers in a sitting position and after 1, 3, and 10 minutes in a supine position. In the second part of the experiment (a 7-day -6 degrees head-down tilt [HDT]), IOP (at 8 am, 12 am and 6 pm) and corneal thickness (12 am) were monitored in 8 female volunteers before, during, and after the HDT period. Blood pressure, hematocrit, plasma volume and osmolality, and plasma catecholamines concentrations were also measured.
Intraocular pressure was significantly higher in the supine position (16.1 +/- 3.6 mm Hg) than in the sitting position, with a mean pressure difference of 2.23 +/- 2.9 mm Hg after 1 minute, 0.9 +/- 3 mm Hg after 3 minutes, and 1.9 +/- 3.8 mm Hg after 10 minutes in a supine position (P < 0.001). During the period of HDT, IOP values decreased significantly on the fifth day (13.3 +/- 1.6 mm Hg, P = 0.03) and the seventh day (12.7 +/- 1.7 mm Hg, P = 0.02) when compared with IOP in the supine position (14.26 +/- 2 mm Hg). The corneal thickness increased significantly (P < 0.0001) at day 5 (549.25 +/- 48.7 microm) and day 7 (540.31 +/- 46.9 microm) compared with baseline (532.45 +/- 38.6 microm). Two days after the end of the HDT bedrest, the mean supine IOP significantly increased (14.1 +/- 1.8 mm Hg, P = 0.003) and corneal thickness was similar to that found at baseline. The mean decrease of IOP was positively correlated with that of the plasma volume (-10%, r = 0.61, P = 0.02) and negatively correlated with the mean rise of hematocrit (r = -0.5, P = 0.07), variables that are considered to be indirect measures of plasma dehydration.
During a 7-day HDT bedrest experiment in healthy women, eyes seemed to compensate the moderate rise of IOP described between a sitting and a supine position, and exhibited a slight and progressive average decrease of 1.3 mm Hg. These physiological modifications could be related to an ocular dehydration or to systemic cardiovascular and hormonal variations during bedrest.
确定年轻健康志愿者体位改变引起的眼压（IOP）变化。
使用校准的Pulsair非接触眼压计测量25名女性志愿者双眼在坐姿时以及仰卧1分钟、3分钟和10分钟后的眼压。在实验的第二部分（为期7天的 -6度头低位倾斜[HDT]），对8名女性志愿者在HDT期间之前、期间和之后监测眼压（上午8点、中午12点和下午6点）和角膜厚度（中午12点）。还测量了血压、血细胞比容、血浆容量和渗透压以及血浆儿茶酚胺浓度。
仰卧位时眼压（16.1±3.6 mmHg）显著高于坐位，仰卧1分钟后平均压差为2.23±2.9 mmHg，3分钟后为0.9±3 mmHg，10分钟后为1.9±3.8 mmHg（P<0.001）。在HDT期间，与仰卧位眼压（14.26±2 mmHg）相比，第5天（13.3±1.6 mmHg，P = 0.03）和第7天（12.7±1.7 mmHg，P = 0.02）眼压值显著降低。与基线（532.45±38.6微米）相比，第5天（549.25±48.7微米）和第7天（540.31±46.9微米）角膜厚度显著增加（P<0.0001）。HDT卧床休息结束两天后，仰卧位平均眼压显著升高（14.1±1.8 mmHg，P = 0.003），角膜厚度与基线时相似。眼压的平均降低与血浆容量的降低呈正相关（-10%，r = 0.61，P = 0.02），与血细胞比容的平均升高呈负相关（r = -0.5，P = 0.07），这些变量被认为是血浆脱水的间接指标。
在健康女性进行的为期7天的HDT卧床休息实验中，眼睛似乎补偿了坐位和仰卧位之间描述的眼压适度升高，并表现出平均1.3 mmHg的轻微且逐渐降低。这些生理变化可能与卧床休息期间的眼部脱水或全身心血管和激素变化有关。
