The pupil is a round hole in the iris of the eye, a kind of diaphragm that can change its diameter. Sensitive photoreceptors of the eye react with unimaginable accuracy to changes in the flow of light rays. Depending on the intensity of illumination, a special muscle reduces or increases the size of the hole, thereby regulating the amount of light that enters the inner shell - the retina. A change in pupil diameter is one of the most important indicators of the function and general condition of the brain. Not without reason, in any feature film devoted to emergency medicine, you can see how a doctor shines a narrow flashlight into the eye of a patient in order to cause reflex pupillary constriction and assess the level of consciousness.
Change in pupil size can be related to more than just the amount of light. For example, when a person sees something of great interest, the pupil changes size intensely.
If the pupils are dilated, the reasons for this may be the following: strong emotions, excitement, increased attention, pain,fear. But there is also a painful permanent expansion, which eventually leads to damage to the optic nerves.
Pupil and disease
Persistent dilation of pupils is called mydriasis by physicians. This condition can be caused by medications or strong chemicals (including drugs).
However, doctors say that if the pupils are dilated, the causes need to be determined as quickly as possible. Mydriasis can cause injuries (both to the eye itself and to the brain), as well as stroke, epilepsy, and a number of other brain diseases. However, at different ages, the reasons for persistent changes in pupil size are different. If an adult has dilated pupils, the causes of this phenomenon may lie in lesions and diseases of the cerebral vessels.
But if this is observed in newborns and young children, it is not always necessary to worry. If dilated pupils are noted in a child, the reasons for this phenomenon may lie in congenital genetic characteristics. It is noteworthy that in newborns, the pupils are completely different sizes. In most cases, there is no need to worry. But if the pupil is dilated by more than 1 mm and does not return to its original size under the influence of light, then this is a reason to see a doctor.
Mydriasis in a teenager is a sign of trouble
As mentioned above, drugs also cause a change in the size of the pupil - cocaine, LSD, marijuana, amphetamines and other deadly substances. If a teenager has dilated pupils, the reasons for this, asusually disrespectful. A persistent increase in pupil size is seen as a physiological sign of drug use. However, parents and teachers should remember that the opposite phenomenon (persistent pupillary constriction) is also a sure sign of intoxication with opiate drugs. At the same time, the pupil is unusually narrow and does not expand at all even in complete darkness. But even in adolescents, pupils may be dilated due to illness. We should not forget that mydriasis makes it possible to suspect a disease of the nervous system or blood vessels. In addition, pupils of different sizes are an early sign of brain tumors or severe infection.
If you notice that you or your family members have dilated pupils, the reasons must be determined as soon as possible. Wide pupils give the eyes beauty, but they can also signal trouble and illness.
