Medically reviewed by Andrew Greenberg, MD Key Takeaways Pupils naturally dilate in low light to allow more light into the ...

Normally, a person's pupils naturally widen (or dilate) in low-light environments to allow more light into the eye. However, in a new study, researchers reported that a person's pupils also dilate ...

The iris is a structure behind the transparent cornea of the eye. It has a circular opening called the pupil that changes size in response to the light level. Your pupils are usually the same size as ...

Our eyesight declines with age and poor lighting or strong contrasts between light and dark can limit the ability of older people to react in everyday life, resulting in a negative impact on the sleep ...

A novel ophthalmic spray containing 1% tropicamide and 2.5% phenylephrine was noninferior to traditional eye drops for producing changes in the maximum pupil diameter and percentage of pupillary ...