Department of Ophthalmology, University Hospital Erlangen, Germany.
Friedrich-Alexander-University Erlangen-Nürnberg, Germany.
Invest Ophthalmol Vis Sci. 2021 May 3;62(6):17. doi: 10.1167/iovs.62.6.17.
The purpose of this study was to characterize summation of temporal L- and M-cone contrasts in the parvo- (P-) and magnocellular (M-) pathways in glaucoma and the relationship between the respective temporal contrast sensitivities (tCS) and clinical parameters.
Perifoveal tCS to isolated or combined L- and M-cone contrasts (with different contrast ratios, and therefore different luminance and chromatic components) were measured at different temporal frequencies (at 1 or 2 Hz and at 20 Hz) using triple silent substitution in 73 subjects (13 healthy, 25 with glaucoma, and 35 with perimetric glaucoma). A vector summation model was used to analyze whether perception was driven by the P-pathway, the M-pathway, or both. Using this model, L- and M-cone input strengths (AL, AM) and phase differences between L- and M-cone inputs were estimated.
Perception was always mediated by the P-pathway at low frequencies, as indicated by a median phase angle of 179.84 degrees (cone opponency) and a median AL/AM ratio of 1.04 (balanced L- and M-cone input strengths). In contrast, perception was exclusively mediated by the M-pathway at higher frequencies (input strength not balanced: AL/AM = 2.94, median phase angles = 130.17 degrees). Differences in phase were not significant between diagnosis groups (Kruskal-Wallis = 0.092 for P- and 0.35 for M-pathway). We found differences between groups only for the M-pathway (L-cone tCS deviations at 20 Hz were significantly lower in the patients with glaucoma P = 0.014, with a strong tendency in M-cones P = 0.049). L-cone driven tCS deviations at 20 Hz were linearly correlated with perimetric mean defect (MD) and quadratically correlated with retinal nerve fiber layer (RNFL) thickness.
Unaltered phase angles between L- and M-cone inputs in glaucoma indicated intact temporal processing. Only in the M-pathway, contrast sensitivity deviations were closely related to diagnosis group, MD, and RNFL thickness, indicating M-pathway involvement.
本研究旨在描述青光眼中小窝（P-）和大窝（M-）通路中 L-和 M-锥体对比度的时间总和，并探讨各自的时间对比敏感度（tCS）与临床参数之间的关系。
使用三重静默替换法，在 73 名受试者（13 名健康人、25 名青光眼患者和 35 名周边青光眼患者）中，测量了不同时间频率（1 或 2 Hz 和 20 Hz）下单独或组合的 L-和 M-锥体对比度（对比度比不同，因此亮度和色度成分也不同）的周边 tCS。采用矢量和模型分析感知是由 P 通路、M 通路还是两者共同驱动。使用该模型，估计了 L-和 M-锥体的输入强度（AL、AM）以及 L-和 M-锥体输入之间的相位差。
在低频时，感知始终由 P 通路介导，这表明中位相位角为 179.84 度（锥体对立），中位 AL/AM 比值为 1.04（L-和 M-锥体输入强度平衡）。相比之下，在较高频率时，感知完全由 M 通路介导（输入强度不平衡：AL/AM=2.94，中位相位角=130.17 度）。在不同诊断组之间，相位差异无显著性差异（P 通路的 Kruskal-Wallis 值为 0.092，M 通路为 0.35）。我们仅在 M 通路中发现了组间差异（青光眼患者的 L-锥体 20 Hz tCS 偏差明显较低，P=0.014，M-锥体有强烈趋势，P=0.049）。20 Hz 时 L-锥体驱动的 tCS 偏差与周边平均缺损（MD）呈线性相关，与视网膜神经纤维层（RNFL）厚度呈二次相关。
青光眼患者的 L-和 M-锥体输入之间的相位角未发生改变，表明其时间处理功能完整。仅在 M 通路中，对比敏感度偏差与诊断组、MD 和 RNFL 厚度密切相关，表明 M 通路受累。
