Devers Eye Institute, Legacy Health, Portland, Oregon, United States.
Invest Ophthalmol Vis Sci. 2023 Jun 1;64(7):30. doi: 10.1167/iovs.64.7.30.
Tissue stiffening and alterations in retinal blood flow have both been suggested as causative mechanisms of glaucomatous damage. We tested the hypothesis that retinal blood vessels also stiffen, using laser speckle flowgraphy (LSFG) to characterize vascular resistance.
In the longitudinal Portland Progression Project, 231 eyes of 124 subjects received LSFG scans of the optic nerve head (ONH) and automated perimetry every 6 months for six visits. Eyes were classified as either "glaucoma suspect" or "glaucoma" eyes based on the presence of functional loss on the first visit. Vascular resistance was quantified using the mean values of several instrument-defined parameterizations of the pulsatile waveform measured by LSFG, either in major vessels within the ONH (serving the retina) or in capillaries within ONH tissue, and age-adjusted using a separate group of 127 healthy eyes of 63 individuals. Parameters were compared against the severity and rate of change of functional loss using mean deviation (MD) over the six visits, within the two groups.
Among 118 "glaucoma suspect" eyes (average MD, -0.4 dB; rate, -0.45 dB/y), higher vascular resistance was related to faster functional loss, but not current severity of loss. Parameters measured in major vessels were stronger predictors of rate than parameters measured in tissue. Among 113 "glaucoma" eyes (average MD, -4.3 dB; rate, -0.53 dB/y), higher vascular resistance was related to more severe current loss but not rate of loss.
Higher retinal vascular resistance and, by likely implication, stiffer retinal vessels were associated with more rapid functional loss in eyes without significant existing loss at baseline.
组织变硬和视网膜血流改变都被认为是青光眼损伤的致病机制。我们通过激光散斑血流图（LSFG）来表征血管阻力，从而验证视网膜血管也会变硬的假说。
在波特兰进展项目的纵向研究中，124 名受试者的 231 只眼每 6 个月接受一次视神经头（ONH）的 LSFG 扫描和自动视野检查，共进行了 6 次访视。根据首次就诊时的功能丧失情况，将眼睛分为“青光眼疑似”或“青光眼”眼。使用 LSFG 测量的脉动波形的几个仪器定义参数的平均值来量化血管阻力，这些参数要么是在 ONH 内的主要血管（为视网膜服务）中，要么是在 ONH 组织内的毛细血管中，并用另一组 63 名个体的 127 只健康眼的年龄进行校正。在两组中，将参数与功能丧失的严重程度和变化率（6 次访视中的平均偏差（MD））进行比较。
在 118 只“青光眼疑似”眼中（平均 MD，-0.4dB；速率，-0.45dB/y），较高的血管阻力与较快的功能丧失有关，但与当前的损失严重程度无关。在主要血管中测量的参数比在组织中测量的参数更能预测速度。在 113 只“青光眼”眼中（平均 MD，-4.3dB；速率，-0.53dB/y），较高的血管阻力与当前更严重的损失有关，但与损失速度无关。
较高的视网膜血管阻力，以及可能由此导致的更硬的视网膜血管，与基线时无明显现有损失的眼睛更快的功能丧失有关。
