eyes
6 questions tagged eyes — spanning every one of the seven Ws.
How Do Our Eyes Adjust to the Dark?
In darkness the pupils widen and the retina's light-sensitive rod cells rebuild a pigment called rhodopsin, greatly boosting night vision over about 20 to 40 minutes.
How Do Contact Lenses Correct Vision?
Contact lenses sit on the tear film over the cornea and bend light before it enters the eye, so it focuses correctly on the retina.
Why do our pupils get smaller in bright light?
The pupils shrink to limit how much light reaches the retina. This protects vision and helps the eye focus more sharply.
Why do our eyes sometimes make tears when we cut onions?
Cutting onions releases a sulfur-containing gas that irritates the eyes. The eyes produce tears to wash the irritant away.
Why do our pupils look different sizes in some people?
Unequal pupil size can be normal, but it can also reflect differences in nerve control or eye health. Doctors call unequal pupils anisocoria.
How do the pupils change size in different light?
The iris muscles change pupil size to control how much light enters the eye. Pupils usually get smaller in bright light and larger in darkness.