La pupil is the black dot in the center of the iris. Thanks to its power of contraction and expansion, it is responsible for regulating the amount of light that enters the ocular structure.
When we are in a very dark environment, the pupil dilates to increase the amount of light that enters the eye. This state of pupillary dilation is known in ophthalmology by the name of mydriasis.
En Área Oftalmológica Avanzada We explain what mydriasis is and what diseases can cause it for a long time.
What is mydriasis?
The pupils dilate as a result of a natural reflex in the absence of light. This state is known as mydriasis, and it is a completely normal response of the ocular system.
Some diseases can cause the pupil to dilate for a long time. In this case, we would be talking about a pathological mydriasis, which can remain even in very bright environments.
Differences miosis vs mydriasis
Mydriasis is the opposite of myosis, which is the contraction of the pupil in very bright environments or very bright light. When the environment is very bright, such as a beach at 12 noon, it contracts to prevent excess light from entering the eye.
Both mydriasis and miosis are natural responses that help regulate the amount of light that enters from the outside to the retina Of the eye. Both reflexes are necessary for good vision.
Causes
Mydriasis can be caused by different factors, the most common are:
- Ambient light: when we wake up after sleeping for many hours, the pupils are dilated until they adapt to the external light. Dark or dimly lit spaces also stimulate mydriasis.
- Mood changes: the pupils can also dilate when we experience sudden changes in mood. Excitement, nerves, and enthusiasm can cause mydriasis.
- Stimulant substances: drugs and alcohol produce such excitation of the muscle fibers of the iris, which can cause mydriasis.
Possible diseases related to dilated pupils
Occasionally, mydriasis is caused by the following diseases:
- Cerebrovascular accidents, hemorrhages and neurological diseases, which can modify the size of the pupils.
- The trigeminal nerve controls different parts of the face. When this nerve is affected by head trauma, it can cause permanent mydriasis.
- The Claude-Bernard-Horner syndrome. In addition to causing mydriasis, it can cause sinking of the eye and drooping of the eyelid.
- Symmetrical areactive mydriasis is a condition that occurs when the pupil remains dilated in very bright spaces. This may indicate serious brain damage.
- Eye injuries can affect the condition of the pupil. Some of these conditions can be glaucoma, iris ischemia and eye trauma.
Transmission
The treatment of mydriasis depends exclusively on its cause.
Pathological mydriasis is an emergency that must be seen immediately by an ophthalmologist. Because it can be caused by neurological problems, it is important to check your blood pressure and control it if it is very high.
Its diagnosis may depend on the other symptoms that the patient presents. For this reason, if the pupil is permanently dilated, it is best to go to the emergency room.
If you have one of these pathologies mentioned, do not hesitate to come to our ophthalmological clinic. In Área Oftalmológica Avanzada, we have experts in the diagnosis and treatment of mydriasis. We will wait for you!
