Optic nerve head (ONH) neuroretinal rim thickness, quantified as minimum rim width (BMO-MRW), is a sensitive measure for assessing early glaucomatous disease. The BMO-MRW is sensitive to transient fluctuations in intraocular pressure (IOP), but the time course over which BMO-MRW decreases and recovers with changes in IOP remains unknown. The goal of this study was to investigate the dynamics of BMO-MRW changes over 2-h periods of mild or moderate IOP elevation, and subsequent recovery, in healthy non-human primate eyes. Eight non-human primates were included in the study. For each animal, in two different sessions separated by at least 2 weeks, the anterior chamber IOP of one eye was maintained at either 25 mmHg or 40 mmHg for 2 h and, subsequently, at 10 mmHg for 2 h. For the duration of anterior chamber cannulation, optical coherence tomography (OCT) radial scans centered on the ONH were acquired every 5 min and used to quantify BMO-MRW. An exponential decay or rise to maximum function was used to determine the extent and rate of structural change. Additionally, Bruch's membrane opening (BMO) area, BMO height/displacement, and BMO-referenced anterior lamina cribrosa surface depth (BMO-ALCSD) were computed from radial scans. A circular scan was used to quantify retinal nerve fiber layer thickness (RNFLT) and circumpapillary choroid thickness. The primary results demonstrated that the BMO-MRW changed over an extended duration, while BMO displacement was rapid and remained stable with sustained IOP. The mean maximum predicted BMO-MRW thinning following 2 h of IOP elevation was significantly related to pressure (34.2 ± 13.8 μm for an IOP of 25 mmHg vs 40.5 ± 12.6 μm for 40 mmHg, p = 0.03). The half-life for BMO-MRW thinning was 21.9 ± 9.2 min for 25 mmHg and 20.9 ± 4.2 min for 40 mmHg, not significantly different between IOP levels (p = 0.76). Subsequently, after 2 h of IOP at 10 mmHg, all animals exhibited partial recovery of BMO-MRW with similar degrees of persistent residual thinning for the two IOP levels (21.5 ± 13.7 vs 21.0 ± 12.3 μm, p = 0.88). Similar to BMO-MRW, choroid thickness exhibited gradual thinning with IOP elevation and residual thinning following IOP reduction. However, there was no significant change in BMO area or BMO-ALCSD in either experimental session. The RNFLT gradually decreased over the duration of IOP elevation, with continued decreases following IOP reduction for the 40 mmHg session, resulting in total changes from baseline of -2.24 ± 0.81 and -2.45 ± 1.21 μm for 25 and 40 mmHg, respectively (p < 0.001). The sum of the results demonstrate that the ONH neural tissue is sensitive to changes in IOP, the effects of which are gradual over an extended time course and different for increased vs. decreased pressure. Understanding the duration over which IOP influences BMO-MRW has important implications for studies investigating the effects of IOP on the ONH. Additionally, individual variability in ONH response to IOP may improve our understanding of the risk and progression of disease.

中文翻译：

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在健康的非人类灵长类动物眼中，神经视网膜边缘对眼压的瞬时变化做出反应。

视神经头（ONH）神经视网膜边缘厚度，以最小边缘宽度（BMO-MRW）量化，是评估早期青光眼疾病的敏感措施。BMO-MRW对眼内压（IOP）的短暂波动敏感，但是BMO-MRW随IOP的变化而下降和恢复的时间仍然未知。这项研究的目的是调查健康的非人灵长类动物眼睛在轻度或中度眼压升高2小时内BMO-MRW变化的动态，以及随后的恢复情况。这项研究包括了八只非人类的灵长类动物。对于每只动物，在至少间隔2周的两个不同阶段中，一只眼睛的前房IOP维持在25 mmHg或40 mmHg持续2 h，然后保持在10 mmHg 2 h。在前房插管期间 每5分钟采集一次以ONH为中心的光学相干断层扫描（OCT）径向扫描，并将其用于量化BMO-MRW。使用指数衰减或上升到最大函数来确定结构变化的程度和速率。此外，还通过径向扫描计算了布鲁赫的膜开口（BMO）面积，BMO高度/位移和BMO参照的筛前筛板表面深度（BMO-ALCSD）。圆形扫描用于量化视网膜神经纤维层厚度（RNFLT）和乳头状脉络膜厚度。初步结果表明，BMO-MRW在较长的时间内发生了变化，而BMO的置换迅速且在持续的IOP下保持稳定。眼压升高2小时后，平均最大预测BMO-MRW变薄与压力显着相关（25 mmHg的眼压为40时，压力为34.2±13.8μm。40 mmHg为5±12.6μm，p = 0.03）。BMO-MRW减薄的半衰期对于25 mmHg为21.9±9.2分钟，对于40 mmHg为20.9±4.2分钟，IOP水平之间无显着差异（p = 0.76）。随后，在10 mmHg的IOP 2小时后，所有动物均表现出BMO-MRW的部分恢复，并且在两个IOP水平下持续残留变薄的程度相似（21.5±13.7 vs 21.0±12.3μm，p = 0.88）。与BMO-MRW相似，脉络膜厚度随着IOP升高而逐渐变薄，而IOP降低则残留变薄。但是，在任何一个实验阶段，BMO面积或BMO-ALCSD都没有显着变化。RNFLT在眼压升高期间逐渐降低，在40 mmHg疗程眼压降低后持续降低，导致基线的总变化为-2.24±0.81和-2.45±1。25和40 mmHg分别为21μm（p <0.001）。结果的总和表明，ONH神经组织对IOP的变化敏感，IOP的变化在延长的时间过程中是渐进的，并且对于压力升高与降低的影响不同。了解IOP影响BMO-MRW的持续时间对调查IOP对ONH的影响的研究具有重要意义。此外，ONH对IOP反应的个体差异可能会增进我们对疾病风险和进展的了解。了解IOP影响BMO-MRW的持续时间对调查IOP对ONH的影响的研究具有重要意义。此外，ONH对IOP反应的个体差异可能会增进我们对疾病风险和进展的了解。了解IOP影响BMO-MRW的持续时间对调查IOP对ONH的影响的研究具有重要意义。此外，ONH对IOP反应的个体差异可能会增进我们对疾病风险和进展的了解。