announcement

Help someone with useful health advice.

Causes of Dilated Pupils

Causes of Dilated Pupils

Widening of the pupils in order to allow more light to pass through the eyes is known as pupil dilation. This article explores some of the most commonly found causes leading to dilated pupils.
Rahul Thadani
Last Updated: Apr 23, 2018
The eyes are the organs of sight. These are a part of the sensory system for vision that allow us to see things, and the pupils play an important role in facilitating vision, as it is through the pupil that light enters the retina. Pupils are apertures or openings that are located in the center of the iris of the eye. These must not be confused with the eyeballs, as the eyeballs contain a variety of muscles and tissues that perform a myriad number of functions. Our eyes are adapted to react to stimulus. This is done through involuntary reflexes in which the size of the pupils change. There are a number of reasons behind the pupil getting enlarged, causing a condition medically known as Mydriasis. Dilated pupils are common in old age, but these can also be observed in people of all other age groups due to different reasons.
In order for the eye to see things, light must be permitted to enter the eye and reach the cells that sensitize to this light. These cells are present towards the rear portion of the eyes, and it is the pupil which acts as the opening through which the light enters the eye and reaches these cells. When the pupils dilate or widen, a greater amount of light passes through to the rear of the eyes. This occurs with the help of the iris, which is a circular muscular ring that is present around the pupil. The expansion and the contraction of the iris causes the pupil to widen or narrow down.
Reasons for Dilated Pupils
There are a few well-known factors that may bring on this situation. These causes are known to eye specialists and medical experts around the world. Dilation of pupils is usually a harmless condition, unless it is occurring for extended periods of time. In that case, overexposure to light may occur, and the eye could get damaged, as a result. Some of the reasons which cause dilation are as follows:
Substance Abuse
The constant use of certain substances or drugs by an individual is considered to be one of the most widespread causes for this condition. These drugs may have other side effects too. Almost every brand of illegal drug is known to be a cause of this condition. Out of the many signs that users of marijuana, cocaine, ecstasy, mushrooms and LSD show, dilated pupils are one of the first things that medical specialists look for. Alcohol abuse is another of the causes for dilated pupils too.
Medication
When a person goes to an eye specialist for a checkup, the doctor dilates his eye with the help of specific eye drops to look into the inner structures. After the checkup, it is advised to wear black glass for a fixed period of time. Exposing the eyes to light before the stipulated time lets a large amount of light to enter through the dilated pupils, thus damaging the eyes.
Light
Light affects the functioning of the eyes in a specific manner. When a person walks into a dark area, the pupils expand to allow more light to enter into the eyes, so that a clearer image can be formed in the brain. On the other hand, when a person enters a bright area, the pupils contract to adjust the amount of light that needs to enter the eyes. This frequency between light and dark should be minimal, as frequent widening or contracting of the pupils can be quite harmful to the eyes.
Poison
Another well-known cause of pupil dilation is exposure to some kind of biological or chemical poison. These have an adverse effect on the body, and the most common symptoms that they produce are dilated pupils. Out of the many causes, this is possibly the most dangerous one, as the poison can have certain other effects on the body as well. If you feel that you are experiencing dilated pupils due to exposure to poison of some kind, medical help must be sought immediately to prevent the poison from spreading and affecting any other parts of the body.
Excitement or Sexual Arousal
Scientific studies have shown that the act of excitement or arousal in the human body is linked to the central nervous system in some way. When a person is aroused or sees someone they find attractive, the nervous system plays a part in causing a lot of effects on the body. Dilation of the pupils is one of the common effects that sexual arousal has on the body, since it is the nervous system that controls the iris of each eye as well.
Brain Injury
An injury to the brain in any accident or trauma can be a specific cause for the dilation of the pupils. The pupils are interconnected to the brain with the help of the nerves. An injury to the brain affecting these sensory nerves would result in the improper functioning of the pupils.
Pupil dilation is not something very serious in itself, but if it lasts involuntarily for a stretched period of time, it could damage the eye severely. In such a scenario, the eye must be protected from excessive sunlight. When you read about the various causes, you get slightly alarmed, as this condition could imply certain other unwanted scenarios like drug addiction or poisoning. If you are witnessing this condition in a child, you must consult a doctor about the implications of the condition.
Disclaimer: This HealthHearty article is for informative purposes only, and should not be substituted for medical advice when required.