Medically reviewed by Diana Apetauerova, MD Key Takeaways Anisocoria is when the pupils of your eyes are different sizes.

A person’s pupils may be of different sizes (anisocoria) for several reasons, including physical trauma, response to light, and infection. The condition may also be present from birth. Pupils, or the ...

The pupil literally plays a central role in vision: it is the opening in the middle of the eye that regulates how much light falls on the retina. If it is dark, the pupil becomes large and lets a lot ...

Dilated pupils mean that your pupils appear larger in size. The most common reason for dilated pupils is low light in a dark room since lower light causes your pupils to grow. Dilated pupils are also ...

Rayna Bell, a herpetology expert and curator at the California Academy of Sciences, told Snopes it's true that some frogs have heart-shaped pupils, adding that the photo in question appears to be a ...