Introduction:
The pupil is a dark adjustable circular opening in the center of the eye that enlarges or contracts to let light enter. The average pupil size ranges between 2.5 to 4.0 millimeters. However, it can approach a maximum size of three to eight millimeters. The pupil plays an essential role in our vision, similar to the camera's aperture allowing images to be seen and captured. The iris is a flat ring-shaped membrane located behind the cornea. It is made up of muscle fibers and connective tissues providing the ability to control the amount of light that enters the pupil by using particular muscles. The muscular iris moves to shrink the pupil. In daylight, the pupils become smaller, and wider at night, making them grow larger. It is an involuntary function controlled by the brain.
What Is Mydriasis?
Sometimes the pupils can dilate unusually without any change in the light; this medical condition is known as mydriasis. It is also termed as fixed pupils. Pupils are dilated when the black center of the eye is more significant than usual. The majority of the time, dilated pupils will naturally return to their usual size. Usually, the size of the pupils in each eye is the same. Anisocoria is the medical term for mydriasis that only affects one eye.
What Are the Common Causes of Dilated Pupils?
The most common causes of dilated pupils are -
1. Eye Examinations - During eye exams, eye professionals may apply special eye drops called mydriatics to dilate the pupils. After this procedure, the pupils will dilate for 15 to 30 minutes, enabling the specialist to obtain a clear view of both the retina and the optic nerve. Observing these parts of the eye can offer important clues about eye health and warning signs of significant issues.
2. Medications - Few medications can affect the muscles that control pupils and result in pupil dilations, such as:
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Anti-seizure medications.
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Antihistamines.
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Medications for Parkinson's disease.
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Antidepressant medications.
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Antinausea medications.
3. Eye Injuries (Trauma) - Some eye injuries, such as eyeball fractures or orbital fractures, can disrupt the nerves or iris muscles that control pupil size. Pupil dilation may also occur following eye surgery, such as cataract removal or corneal transplant.
4. Sexual Stimulations - Increasing oxytocin levels generally induces the pupils to dilate. Oxytocin is a hormone and neurotransmitter that acts as a chemical messenger during sexual arousals and also helps women through labor, encourages parent-child interaction, and influences testosterone levels.
5. Head Injury - After a brain tumor, stroke, or head accident, the pressure that builds up inside the brain may damage the iris muscles that control the pupil’s natural opening and closing.
6. Illicit Drugs Usage - Pupil dilations are the primary key indicators for someone who has used illegal drugs such as Cocaine, amphetamines, ecstasy, etc. The pupil dilations are controlled by two muscles, muscles of the iris and the sphincter muscle. Depending on the drugs being taken, the neurotransmitters in the brain that helps to control pupil dilation are affected, causing the pupils to dilate. In addition, the sympathetic and parasympathetic nervous systems are affected by drugs, which causes pupil dilation. The parasympathetic nervous system regulates an individual's autonomic physiological functions while resting and causes the sphincter reaction. The sympathetic nervous system regulates the body's fight-or-flight reaction and activates the dilator in the eye.
7. Anxiety - Sometimes, anxiety may also lead to pupil dilations due to the release of adrenaline. Adrenal glands release chemicals and hormones that cause the body to go into fight or flight mode by sending nerve impulses to organs. An increase in heart rate, blood pressure, dilated pupils, and profuse sweating can all be signs of stress-induced adrenaline hormone reactions.
What Are the Signs and Symptoms of Pupil Dilation?
The signs and symptoms of pupil dilation depends on how the light enters the eye. The symptoms include:
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Distorted vision.
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Vey sensitivity to light.
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Headache.
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Dizziness.
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Eye irritation.
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Sleep Disturbance.
How Can Pupil Dilation Be Treated?
The treatment for pupil dilation is carried out by initially assessing the cause and following the required medical interventions. The full functionality of the eyes can be protected using various treatment modalities. Dilated pupils usually resolve independently without treatment, especially if eye drops cause them. Therefore, many medical professionals would only advise patients to wait for the drug's effects to subside and avoid it. Additional treatment is required for more severe cases of mydriasis includes:
1. Wear Sunglasses
For the majority of patients, light sensitivity is their main issue. They may feel uncomfortable, especially on a sunny day, because their pupils cannot close to block out excess light.
Dilated pupils are more sensitive to sunlight than usual. Avoid such situations and wear sunglasses while going outside, even indoors, until the medication's effects wear off. Having someone pick up from an appointment is preferable because driving is dangerous due to blurred vision and light sensitivity.
2. Surgery
In severe cases, surgery may be necessary for the brain and eye injuries to reconstruct the nerves or eye structures.
3. Artificial Contact Lenses
Artificial contact or prosthetic soft lenses can help mydriasis patients by effectively blocking the light and removing uncomfortable visual disturbances. Iris occlusion prosthetic contact lenses are advisable for patients with dilated pupils, glare, and photophobia (discomfort for sources of bright light) complaints.
4. Rehabilitation for Drug Abuse
If anyone suspects drug abuse from family or friends, there are multiple ways to help the situation. It may be helpful to know which drugs produce dilated pupils, but it is also critical to learn more about their unique problems to help them find the best course of treatment.
Speak up and express concern to them. Instead of making accusations or passing judgment, share the observations and support with them. It is essential to assist them and motivate them to visit a drug recovery center for assistance. Let them take responsibility for their actions, which is a crucial step on their journey to recovery.
Conclusion:
Pupil dilation usually occurs based on the variations of light. Mydriasis may develop from various causes, such as minor side effects from medications, eye and brain injuries, anxiety, and illicit drugs. If someone experiences the same signs and symptoms, advice to contact any eye care professionals as early as possible.
