You need that light background for the pupil to work appropriately to minimize the amount of light coming in.

让瞳孔缩小，减少进入眼睛的光线，你就需要有一个明亮的背景。

Things like: open mouths, wide or small pupils, blinks, nose licks, whisker movements and ear positions.

这些部动作包括：张嘴、瞳孔变或缩小、眨眼、舔鼻子、须动作和耳朵的转动。

Why, is one of my pupils getting all small?

啥 我的其中一个瞳孔又缩小吗？

In fact, cat pupils are so flexible that their maximum area is 135 times greater than their minimum area — whereas our pupils only shrink and expand 15-fold.

事实上，猫的瞳孔非常灵活，它们的瞳孔积是小积的 135 倍，而我们的瞳孔只能缩小或扩 15 倍。

If a pancoast tumor pushes on or invades these sympathetic nerves, it can cause miosis - a small or constricted pupil, ptosis - a droopy eyelid, and anhydrosis - a failure to sweat, all on the ipsilateral, or same side, of the face as the nerve.

如果肺上沟瘤向上挤压或侵袭交感神经，则会出现瞳孔缩小、上睑下垂、无汗等症状，这些都发生于神经支配的同侧部。