A cat with two differently sized pupils has captured viral attention online after his picture was shared on Tuesday. Ricardo—who uses the Reddit handle RikTehSpik—lives in Los Angeles with his ...

A video of a cat's pupils dilating at the sight of its favorite toy, going from cute to killer mode, has delighted the internet with over 6.5 million views. In the footage, Luna the long-haired black ...

You look in the mirror and notice that the dark circles in the middle of your eyes are bigger than usual. What's going on? Those dark circles are your pupils, the openings that let light enter your ...

Cats may not speak our language, but their eyes often reveal exactly how they feel about us. From slow blinks that signal affection to unbroken stares that hint at curiosity or even mild irritation, a ...

Mydriasis is the medical term for an unusual dilation or widening of the pupils. There are various causes of this fixed dilation of the pupils. Normally, a person’s pupils dilate when the light is dim ...