Mydriasis (extreme dilation of the pupil): symptoms, causes and treatment

The phenomenon of enlargement of the pupil (dilation of the pupil), which can be caused by factors both internal and external to the body itself, is called mydriasis. This is the reverse process of miosis (reduction in pupil size) and is usually a physiological response to light and brightness.

However, if it remains dilated even without a light stimulus, this is probably no longer a physiological response and could be an indicator of the presence of disease or pathological habits. This is how students work and what factors can cause its dilation, mydriasis.

    How do the students work?

    Pupils are the dark circles that are in the center of our eyes and have the function of transmitting light to the retina to form images. They are surrounded by the iris and the cornea, And consist of an opening that widens or contracts to make room for light. Sometimes it widens to allow us better vision, and sometimes it contracts to protect us from excessively bright stimuli.

    However, students are activated as an automatic response to different factors (not just light), and the system responsible for controlling their activity is the autonomic nervous system, itself divided into system, sympathetic nervous system, and parasympathetic nervous system.

    When the reason for the pupil’s enlargement it is not only related to our physiology and our visionSecond, mydriasis may be an indicator of the existence of a medical condition, or it may indicate that a substance that alters the nervous system has recently been consumed.

      Types and causes of mydriasis

      Mydriasis is a natural and fairly common occurrence that helps us perceive light correctly when it is presented to us in large quantities. However, sometimes mydriasis it is not caused by exposure to light but by other elements that also affect our body.

      Factors that change pupil size causing mydriasis include certain illnesses and drug use. Below we will introduce you

      pharmacological causes

      As the name suggests, the pharmacological causes of mydriasis are those related to drug use. For example, the use of anticholinergics increases dilationAs these are substances that block the transmission of certain chemicals to the eyes.

      Another pharmacological cause is the recreational use of psychotropic substances, such as cocaine, ecstasy, hallucinogens, methamphetamines, or THC. This is because these substances affect the serotonin receptors in the brain (depending on the type of drug, increasing or decreasing its secretion), which causes dilation.

      medical causes

      Medical causes are those that related to surgery which has among its effects the dilation of the pupils. For example, surgeries to treat brain trauma cause mydriasis because they increase pressure on the skull, which affects the eyes.

      On the other hand, eye surgeries sometimes cause significant damage to the nerves that control the pupils or the iris. As a result, students can adopt different ways of reacting to light.

      Physiological and neurophysiological causes

      The physiological and neurophysiological causes of mydriasis are those that are related to our biological or neuroanatomical functions. More specifically, these are the causes related to the functioning of our brain and other related systems.

      The presence of high levels of oxytocin can lead to a temporary case of mydriasis. This is because oxytocin is the substance that is released when we exercise and when we relate to people, both physically and socially. It is also the substance that is released during childbirth.

      Also, mydriasis is usually present in neuropathies of the cranial nerves, which are gradual damage to the nerves surrounding the eye. This affects the oculomotor system and the nerves that cause the pupils to widen or contract.

      For example, parasympathetic nerve palsy. Other causes related to this are strokes, Cranioencephalic trauma, cerebral hernias or epilepsy.

      Finally, one of the cases that includes mydriasis is benign unilateral episode of mydriasis (BEUM), which is a temporary condition of dilated pupil, usually accompanied by headache and pain in the eyes, tenderness to light and blurred vision. This usually happens, for example, during certain migraine episodes.

      Treatment and what to do

      In case of mydriasis, it is important to be careful if the pupil dilation is maintained for a long time (if the light stimulus has disappeared or enough time has passed to adjust to it). In these cases, it is important to consult a specialist doctor.

      As a treatment it is recommended avoid direct sun exposure, As well as to avoid driving. It is also advisable to wear dark glasses (glasses) and to avoid reading texts at close range. Doing the opposite of all of these recommendations can lead to the persistence of mydriasis and drastically affect our vision.

      On the other hand, if it is an indicator of a pathological condition, the specialist may recommend surgical treatment.

      Leave a Comment