👁️ THE HUMAN EYE'S IRIS #Shorts

追加: 2026-05-20

[00:00:00]Iris changes aperture in 1 second. The iris has two muscles. They control the pupil size. This changes how much light enters the eye. In low light, the iris opens up. This lets more light hit the retina. In bright light, it closes to protect the eye. The iris is made of smooth muscle. It can change the pupil size fast. This happens in less than a second. Some people have irises that change color. This can happen when they are excited or tired. It's because the iris muscles are active. The iris controls how much light enters the eye.

[00:00:33]This is important for clear vision.

[00:00:35]Without it, we would be blinded by light or unable to see in the dark. Some animals have vertical irises. This helps them see better in the dark. Their irises can open very wide to let in more light. Understanding the iris is important for eye health. Doctors can use iris scans to detect some diseases.

[00:00:52]The iris can show signs of diabetes or high blood pressure.