Devers Eye Institute, Legacy Health, Portland, Oregon, United States.
Invest Ophthalmol Vis Sci. 2019 Jul 1;60(8):3110-3118. doi: 10.1167/iovs.19-27389.
Blood flow in the optic nerve head (ONH) is known to be reduced in eyes with advanced glaucoma. However, experimental results from non-human primates suggest an initial increase in ONH blood flow at the earliest stages of damage. This study assesses flow and pulsatile hemodynamics across a range of severities to test the hypothesis that this also occurs in human glaucoma.
Laser speckle flowgraphy was used to measure average mean blur rate (MBRave) within ONH tissue (a correlate of capillary blood flow) and the pulsatile waveform in 93 eyes with functional loss and 74 glaucoma suspect/fellow eyes without functional loss. These were compared against results from 92 healthy control eyes. Parameters produced by the instrument's software were age-corrected, then compared between groups using generalized estimating equation models.
The mean MBRave in the control eyes was 12.5 units. In glaucoma suspect/fellow eyes, the mean was 16.4 units, higher with P < 0.0001. In eyes with functional loss, the mean was 13.8 units, lower than eyes without functional loss with P < 0.0001, although still higher than control eyes with P = 0.0096. Analysis of the pulsatile waveform suggested that the deceleration in flow as it approaches its maximum across the cardiac cycle was delayed in glaucoma.
Blood flow within ONH capillaries was higher in glaucoma suspect eyes than in healthy controls. It was less elevated in eyes that had developed functional loss. The mechanisms causing these changes and their relation to concurrent changes in pulsatile hemodynamics remain under investigation.
已知在晚期青光眼患者的视神经头（ONH）中血流减少。然而，来自非人类灵长类动物的实验结果表明，在损伤的最早阶段，ONH 血流最初增加。本研究评估了一系列严重程度的血流和脉动血液动力学，以检验这也发生在人类青光眼的假设。
激光散斑血流仪用于测量 ONH 组织内的平均平均模糊率（MBRave）（毛细血管血流的相关指标）和脉动波形，共涉及 93 只视力丧失眼和 74 只无功能丧失青光眼疑似/同伴眼，这些与 92 只健康对照组进行比较。仪器软件生成的参数经过年龄校正后，使用广义估计方程模型在组间进行比较。
对照组中平均 MBRave 为 12.5 个单位。在青光眼疑似/同伴眼中，平均值为 16.4 个单位，P < 0.0001。在有功能丧失的眼中，平均值为 13.8 个单位，低于无功能丧失的眼，P < 0.0001，尽管与对照组相比仍较高，P = 0.0096。脉动波形分析表明，在整个心动周期中，血流接近最大值时的减速延迟。
ONH 毛细血管内的血流在青光眼疑似眼中高于健康对照组。在已经发生功能丧失的眼中，血流升高幅度较小。导致这些变化的机制及其与脉动血液动力学的并发变化的关系仍在研究中。
