Claus Ilka, Frey Katharina, Hönle Tobias, Brüning Robert, Reichenbach Andreas, Francke Mike, Brunner Robert
Ernst-Abbe-Hochschule, University of Applied Sciences Jena, Germany.
Ernst-Abbe-Hochschule, University of Applied Sciences Jena, Germany; Fraunhofer Institute of Applied Optics and Precision Engineering (IOF), Jena, Germany.
Vision Res. 2019 Jan;154:115-121. doi: 10.1016/j.visres.2018.11.005. Epub 2018 Nov 29.
To further extent our understanding of aquatic vision, we introduce a complete optical model of a goldfish eye, which comprises all important optical parameters for the first time. Especially a spherical gradient index structure for the crystalline lens was included, thus allowing a detailed analysis of image quality, regarding spot size, and wavelength dependent aberration. The simulation results show, that our realistic eye model generates a sufficient image quality, with a spot radius of 4.9 μm which is below the inter cone distance of 5.5 μm. Furthermore, we optically simulate potential mechanical processes of accommodation and compare the results with contradictory findings of previous experimental studies. The quantitative simulation of the accommodation capacity shows that the depth of field is strongly dependent on the resting position and becomes significantly smaller when shorter resting positions are assumed. That means, to enable an extended depth perception with high acuity for the goldfish an adaptive, lens shifting mechanism would be required. In addition, our model allows a clear prediction of the expected axial lens-shift, which is necessary to ensure a sufficient resolution over a large object range.
为了进一步拓展我们对水生动物视觉的理解，我们引入了一个金鱼眼睛的完整光学模型，该模型首次包含了所有重要的光学参数。特别是晶状体中纳入了球面渐变折射率结构，从而能够针对光斑尺寸和波长相关像差对图像质量进行详细分析。模拟结果表明，我们的真实眼睛模型生成了足够的图像质量，光斑半径为4.9微米，低于视锥细胞间距5.5微米。此外，我们对调节的潜在机械过程进行了光学模拟，并将结果与先前实验研究的矛盾发现进行了比较。调节能力的定量模拟表明，景深强烈依赖于静止位置，当假设静止位置较短时，景深会显著变小。这意味着，为了使金鱼能够具有高敏锐度的扩展深度感知，将需要一种适应性的晶状体移位机制。此外，我们的模型能够清晰预测预期的轴向晶状体移位，这对于确保在大物体范围内具有足够的分辨率是必要的。
