In the center, your fovea clearly identifies 3 to 4 letters around where your eyes stop.

在，你的凹清楚地识出你眼睛停下来的地方周围的 3 到 4 字母。

Since the fovea is pretty small, your eyes read text by making quick jerky movements called saccades.

由于很小，你的眼睛就会通过快速跳动的动作来阅读文本，这动作被为扫视。

Cones tend to be concentrated in the fovea.

视锥细胞往往集在凹。

Raptors have an especially deep fovea— a depression in the back of their eye that fits more photoreceptors.

猛禽有一深的凹— —它们眼睛后部的凹陷处适合更多的光感受器。

It's approximately 5 millimeters in diameter and houses another even more specialized region known as the fovea.

它的直径大约为 5 毫米，并包含另一更殊的区域，为凹。

And the fovea is the very center of the retina, about a quarter of a millimeter wide.

凹是视网膜的心， 大约四分之一毫米宽。

The fovea is the area in the center of your vision where the photoreceptors are most densely packed, and where your vision is the sharpest.

凹是你视觉心的区域，那里的光感受器密度最高，你的视觉最清晰。

Of these, only the fovea has a high enough density of cones, the type of photoreceptor cell in your eye that can perceive small details, to make out text on a page.

其，只有的视锥细胞密度足够高，视锥细胞是一种视觉感受器细胞，可以感知小细节，从而辨认出一页纸上的文字。