Department of Physics, Durham University, Durham, UK.
Biosciences Institute, Newcastle University, Newcastle, UK, Present address: Max Planck Institute for Biological Cybernetics, Germany.
J Vis. 2024 Sep 3;24(9):14. doi: 10.1167/jov.24.9.14.
The eye has considerable chromatic aberration, meaning that the accommodative demand varies with wavelength. Given this, how does the eye accommodate to light of differing spectral content? Previous work is not conclusive but, in general, the eye focuses in the center of the visible spectrum for broadband light, and it focuses at a distance appropriate for individual wavelengths for narrowband light. For stimuli containing two colors, there are also mixed reports. This is the second of a series of two papers where we investigate accommodation in relation to chromatic aberration Fernandez-Alonso, Finch, Love, and Read (2024). In this paper, for the first time, we measure how the eye accommodates to images containing two narrowband wavelengths, with varying relative luminance under monocular conditions. We find that the eye tends to accommodate between the two extremes, weighted by the relative luminance. At first sight, this seems reasonable, but we show that image quality would be maximized if the eye instead accommodated on the more luminous wavelength. Next we explore several hypotheses as to what signal the eye might be using to drive accommodation and compare these with the experimental data. We show that the data is best explained if the eye seeks to maximize contrast at low spatial frequencies. We consider the implication of these results for both the mechanism behind accommodation, and for modern displays containing narrowband illuminants.
眼睛具有相当大的色差，这意味着调节需求随波长而变化。考虑到这一点，眼睛如何适应具有不同光谱成分的光？之前的工作没有定论，但总的来说，眼睛在宽带光的可见光谱中心聚焦，在窄带光的单个波长的适当距离聚焦。对于包含两种颜色的刺激，也有混合报告。这是我们研究与色差相关的调节的一系列两篇论文中的第二篇[Fernandez-Alonso, Finch, Love, and Read (2024)]。在本文中，我们首次测量了眼睛在单眼条件下，如何适应包含两个窄带波长的图像，这些图像的相对亮度不同。我们发现眼睛倾向于在两个极端之间进行调节，由相对亮度加权。乍一看，这似乎是合理的，但我们表明，如果眼睛适应更亮的波长，图像质量将最大化。接下来，我们探讨了眼睛可能用于驱动调节的几种假设，并将这些假设与实验数据进行了比较。我们表明，如果眼睛试图最大化低空间频率处的对比度，那么数据可以得到最好的解释。我们考虑了这些结果对调节背后的机制以及包含窄带光源的现代显示器的影响。
