Land Michael
University of Sussex, United Kingdom.
Vision Res. 2019 Sep;162:1-7. doi: 10.1016/j.visres.2019.06.004. Epub 2019 Jul 3.
Good vision requires a near stationary image if motion blur is to be avoided. All animals with good eyesight (principally the vertebrates, arthropods and cephalopod molluscs) have adopted a very similar strategy for achieving this: fixations in which gaze is kept still, with saccades to change gaze direction as fast as possible. In all these groups the stability of fixations is maintained by reflexes that oppose the effects of head or body movement (the vestibulo-ocular reflex in vertebrates), and that oppose drift of the image on the retina (optokinetic and optomotor reflexes). A small number of species of molluscs and arthropods have adopted a different strategy: allowing the retinas to scan across the surroundings to acquire information. The retinas in these animals are all linear structures a few receptors wide, and scan at right angles to their long dimension. The speed of scanning varies with retinal resolution, ensuring that scan speed does not produce deleterious blur.
要避免运动模糊，良好的视力需要近乎静止的图像。所有视力良好的动物（主要是脊椎动物、节肢动物和头足类软体动物）都采用了非常相似的策略来实现这一点：进行注视，即保持目光静止，通过快速眼动来尽可能快地改变注视方向。在所有这些类别中，注视的稳定性通过反射来维持，这些反射可抵消头部或身体运动的影响（脊椎动物中的前庭眼反射），并抵消图像在视网膜上的漂移（视动反射和视动眼反射）。少数软体动物和节肢动物物种采用了不同的策略：让视网膜扫视周围环境以获取信息。这些动物的视网膜都是只有几个感受器宽的线性结构，并与它们的长轴成直角进行扫描。扫描速度随视网膜分辨率而变化，以确保扫描速度不会产生有害的模糊。
