Department of Ophthalmology, Massachusetts Eye and Ear.
Harvard Medical School.
J Glaucoma. 2020 Oct;29(10):952-963. doi: 10.1097/IJG.0000000000001604.
In open-angle glaucoma, when neuroretinal rim tissue measured by volumetric optical coherence tomography (OCT) scans is below a third of the normal value, visual field (VF) damage becomes detectable.
To determine the amount of neuroretinal rim tissue thickness below which VF damage becomes detectable.
In a retrospective cross-sectional study, 1 eye per subject (of 57 healthy and 100 open-angle glaucoma patients) at an academic institution had eye examinations, VF testing, spectral-domain OCT retinal nerve fiber layer (RNFL) thickness measurements, and optic nerve volumetric scans. Using custom algorithms, the minimum distance band (MDB) neuroretinal rim thickness was calculated from optic nerve scans. "Broken-stick" regression was performed for estimating both the MDB and RNFL thickness tipping-point thresholds, below which were associated with initial VF defects in the decibel scale. The slopes for the structure-function relationship above and below the thresholds were computed. Smoothing curves of the MDB and RNFL thickness covariates were evaluated to examine the consistency of the independently identified tipping-point pairs.
Plots of VF total deviation against MDB thickness revealed plateaus of VF total deviation unrelated to MDB thickness. Below the thresholds, VF total deviation decreased with MDB thickness, with the associated slopes significantly greater than those above the thresholds (P<0.014). Below 31% of global MDB thickness, and 36.8% and 43.6% of superior and inferior MDB thickness, VF damage becomes detectable. The MDB and RNFL tipping points were in good accordance with the correlation of the MDB and RNFL thickness covariates.
When neuroretinal rim tissue, characterized by MDB thickness in OCT, is below a third of the normal value, VF damage in the decibel scale becomes detectable.
在开角型青光眼患者中，当通过容积光学相干断层扫描（OCT）测量的神经视网膜边缘组织低于正常值的三分之一时，视野（VF）损伤即可被检测到。
确定可检测到 VF 损伤的神经视网膜边缘组织厚度值。
在一项回顾性的横断面研究中，于学术机构对每只眼（57 只健康眼和 100 只开角型青光眼患者）进行了眼部检查、VF 测试、谱域 OCT 视网膜神经纤维层（RNFL）厚度测量和视神经容积扫描。使用定制算法，从视神经扫描中计算出最小距离带（MDB）神经视网膜边缘厚度。采用“折断棒”回归来估计 MDB 和 RNFL 厚度的转折点阈值，低于该阈值时，在分贝尺度上与初始 VF 缺陷相关。计算了阈值以上和以下的结构-功能关系的斜率。评估了 MDB 和 RNFL 厚度协变量的平滑曲线，以检查独立确定的转折点对的一致性。
VF 总偏差与 MDB 厚度的关系图显示，VF 总偏差存在与 MDB 厚度无关的平台。在阈值以下，VF 总偏差随 MDB 厚度的降低而降低，相关斜率明显大于阈值以上的斜率（P<0.014）。当 MDB 厚度低于 31%，以及上、下 MDB 厚度分别低于 36.8%和 43.6%时，可检测到 VF 损伤。MDB 和 RNFL 转折点与 MDB 和 RNFL 厚度协变量的相关性一致。
当 OCT 中的 MDB 厚度所代表的神经视网膜边缘组织低于正常值的三分之一时，在分贝尺度上可检测到 VF 损伤。
