School of Optometry, Indiana University, Bloomington, Indiana, United States.
Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, Maryland, United States.
Invest Ophthalmol Vis Sci. 2021 Feb 1;62(2):8. doi: 10.1167/iovs.62.2.8.
Psychophysical and genetic testing provide substantial information about color vision phenotype and genotype. However, neither reveals how color vision phenotypes and genotypes manifest themselves in individual cones, where color vision and its anomalies are thought to originate. Here, we use adaptive-optics phase-sensitive optical coherence tomography (AO-PSOCT) to investigate these relationships.
We used AO-PSOCT to measure cone function-optical response to light stimulation-in each of 16 human subjects with different phenotypes and genotypes of color vision (five color-normal, three deuteranopic, two protanopic, and six deuteranomalous trichromatic subjects). We classified three spectral types of cones (S, M, and L), and we measured cone structure-namely cone density, cone mosaic arrangement, and spatial arrangement of cone types.
For the different phenotypes, our cone function results show that (1) color normals possess S, M, and L cones; (2) deuteranopes are missing M cones but are normal otherwise; (3) protanopes are missing L cones but are normal otherwise; and (4) deuteranomalous trichromats are missing M cones but contain evidence of at least two subtypes of L cones. Cone function was consistent with the subjects' genotype in which only the first two M and L genes in the gene array are expressed and was correlated with the estimated spectral separation between photopigments, including in the deuteranomalous trichromats. The L/M cone ratio was highly variable in the color normals. No association was found between cone density and the genotypes and phenotypes investigated, and the cone mosaic arrangement was altered in the dichromats.
AO-PSOCT is a novel method for assessing color vision phenotype and genotype in single cone cells.
心理物理学和遗传学测试为色觉表型和基因型提供了大量信息。然而，这两者都无法揭示色觉表型和基因型如何在个体视锥细胞中表现出来，因为人们认为色觉及其异常起源于视锥细胞。在这里，我们使用自适应光学相敏光相干断层扫描（AO-PSOCT）来研究这些关系。
我们使用 AO-PSOCT 来测量 16 名具有不同色觉表型和基因型的个体（5 名色觉正常、3 名二色视者、2 名一色视者和 6 名二色视异常三原色者）的每个视锥细胞的功能-光刺激的光学反应。我们将三种光谱类型的视锥细胞（S、M 和 L）进行分类，并测量视锥细胞结构，即视锥细胞密度、视锥细胞镶嵌排列和视锥细胞类型的空间排列。
对于不同的表型，我们的视锥细胞功能结果表明：（1）色觉正常者具有 S、M 和 L 视锥细胞；（2）二色视者缺少 M 视锥细胞，但其他方面正常；（3）一色视者缺少 L 视锥细胞，但其他方面正常；（4）二色视异常三原色者缺少 M 视锥细胞，但存在至少两种 L 视锥细胞亚型的证据。视锥细胞功能与受试者的基因型一致，即只有基因阵列中的前两个 M 和 L 基因表达，并与包括二色视异常三原色者在内的视色素估计的光谱分离相关。色觉正常者的 L/M 视锥细胞比例高度可变。在调查的基因型和表型中，未发现视锥细胞密度与两者之间存在关联，二色视者的视锥细胞镶嵌排列发生改变。
AO-PSOCT 是一种评估单个视锥细胞色觉表型和基因型的新方法。
