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

为了让瞳孔缩，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、瞳孔变大或缩、眨眼、舔鼻子、须动作和耳朵的转动。

Why, is one of my pupils getting all small?

为啥 我的其中一个瞳孔又缩了吗？

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，它们的瞳孔最大是最的 135 倍，而我们的瞳孔只能缩或扩大 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、上睑下垂、无汗等症状，这些都发生于神经支配的同侧部。