People often say that the eyes are the windows to the soul. Only eyes can't lie. In fact, what you can really see is the pupil in your eyes. Pupils are 2-8 mm in diameter and usually remain in a medium size.
Doctors believe that the eyes are a mirror of the brain. The relationship between eyes and brain is very close. Five pairs of twelve pairs of cranial nerves emitted by the brain are distributed on the eyes, which directly affect vision and eye movement. Doctors often diagnose brain diseases by peeking at the changes of fundus through the small window of the pupil. For example, fundus arteriosclerosis means cerebral arteriosclerosis.
Doctors also regard the pupil as a sensitive indicator of vital function. As we all know, when the light is strong, the pupil will automatically contract, and when the light is dark, the pupil will spread out-this is called the pupil's response to light. If the pupil is slow to respond to light or disappears, it means that death is coming. Coma patients, with the aggravation of loss of consciousness, pupils will gradually expand, which is a sign of the end of life.
More interestingly, the change of pupil size will reflect some psychological activities. When there is strong interest or motivation, the pupil will expand rapidly. When ancient Persian jewelers sold jewelry, they would ask for it according to the size of customers' pupils. If the flash of diamond rings can dilate the pupils of buyers, businessmen will charge more.
Even better, when a man meets a woman he secretly loves, his pupils will be dilated. On the contrary, when he meets a woman who annoys him, his pupils will shrink. This is the charm of the first impression of "beauty is in the eye of the beholder".
The delicious food presented to us will also make people's pupils bigger, and hungry people will become bigger; When people listen to beautiful music or taste delicious drinks with their tongues, their pupils will also dilate. In addition, when in a state of terror, tension, anger, love, pain, etc., the pupil will be dilated; It will shrink when you are disgusted, tired and upset.