At constant external factors and the full adaptation to it, the pupils are never at rest.Their size is constantly changing due to constant fluctuations of the iris of the eye.

effect of age on the size of the pupils



With age, the size of the pupil varies.Newborn pupil size at rest is 3 mm, but rarely exceeds 5 mm, even in low light.This is due to the fact that the children are not yet fully formed muscles responsible for dilated pupils.

For 2-4 years eye muscles are strengthened, and the size of the pupil is gradually increased to 4-5 mm and thus retained up to 10-12 years.Then it decreases, and 45-55 is equal to 3-4 mm.By old age pupil size is reduced to 1-2 mm, which is due to slower physiological processes in humans.

condition of the body



The state of pupils affected by the overall condition of the human body.Th
ere are special methods of medical treatment that the size and shape of the pupils can determine the status of various internal systems and organs.

is no less the size of the pupils affected by the emotional state of the person.Pupils decrease with fatigue, depression, angry and nervous condition.Conversely, increases in moments of enthusiasm and joy.

External factors



on pupil size affects the light level.In low light or in the dark pupils dilate, and the light of day or in bright light - narrow.Focus look to a large extent affect the state of the eye.When focusing on distant subjects pupils increases, the Middle - reduced.Furthermore, the size of the pupil varies during breathing: inspiratory they expand at the output - narrowed.

Other factors



pupils on condition affects a person's sex.The average pupil diameter of 0.3 mm on the woman higher than in men.This means that women's eyes get more sunlight than men.

People who abuse tobacco, alcohol or drugs, have several pupils are less than people who lead a healthy lifestyle.

Another factor affecting the size of the pupils, a decrease in visual acuity.In nearsightedness, farsightedness, astigmatism, and other eye diseases in humans begin to work less certain eye muscles, resulting in a decrease in pupils.