Jia L, Cepurna W O, Johnson E C, Morrison J C
Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health Sciences University, Portland, USA.
Invest Ophthalmol Vis Sci. 2000 May;41(6):1380-5.
To determine the diural intraocular pressure (IOP) response of Brown Norway rat eyes after sclerosis of the aqueous humor outflow pathways and its relationship to optic nerve damage.
Hypertonic saline was injected into a single episcleral vein in 17 animals and awake IOP measured in both the light and dark phases of the circadian cycle for 34 days. Mean IOP for light and dark phases during the experimental period were compared with the respective pressures of the uninjected fellow eyes. Optic nerve cross sections from each nerve were graded for injury by five independent masked observers.
For fellow eyes, mean light- and dark-phase IOP was 21 +/- 1 and 31 +/- 1 mm Hg, respectively. For four experimental eyes, mean IOPs for both phases were not altered. Six eyes demonstrated significant mean IOP elevations only during the dark phase. Of these, five showed persistent, large circadian oscillations, and four had partial optic nerve lesions. The remaining seven eyes experienced significant IOP elevations during both phases, and all had extensive optic nerve damage.
Episcleral vein injection of hypertonic saline is more likely to increase IOP during the dark phase than the light. This is consistent with aqueous outflow obstruction superimposed on a circadian rhythm of aqueous humor production. Because these periodic IOP elevations produced optic nerve lesions, both light- and dark-phase IOP determinations are necessary for accurate correlation of IOP history to optic nerve damage in animals housed in a light- dark environment.
确定棕色挪威大鼠眼房水流出途径硬化后的昼夜眼压（IOP）反应及其与视神经损伤的关系。
对17只动物的一条巩膜外静脉注射高渗盐水，并在昼夜周期的明相和暗相测量清醒状态下的眼压，持续34天。将实验期间明相和暗相的平均眼压与未注射的对侧眼的相应眼压进行比较。由五名独立的不知情观察者对每条神经的视神经横断面损伤进行分级。
对于对侧眼，明相和暗相的平均眼压分别为21±1和31±1mmHg。对于四只实验眼，两个阶段的平均眼压均未改变。六只眼仅在暗相出现显著的平均眼压升高。其中五只表现出持续的、大幅度的昼夜波动，四只存在部分视神经损伤。其余七只眼在两个阶段均出现显著的眼压升高，且均有广泛的视神经损伤。
巩膜外静脉注射高渗盐水在暗相比明相更易升高眼压。这与房水流出受阻叠加在房水生成的昼夜节律上是一致的。由于这些周期性的眼压升高会导致视神经损伤，因此对于生活在明暗环境中的动物，准确关联眼压历史与视神经损伤需要同时测定明相和暗相的眼压。
