Mydriasis

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Obesity, Sleep & Internal medicine
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Mydriasis
Synonyms
Pronounce	N/A
Specialty	N/A
Symptoms	Dilated pupils
Complications	Photophobia, blurred vision
Onset
Duration
Types	N/A
Causes	Injury, disease, drug use
Risks
Diagnosis	Physical examination, pupillary light reflex test
Differential diagnosis	Adie syndrome, Horner's syndrome, Argyll Robertson pupil
Prevention
Treatment	Addressing underlying cause, miotics
Medication
Prognosis	Depends on underlying cause
Frequency
Deaths

Mydriasis refers to the dilation of the pupils, which is usually due to an underlying condition or exposure to certain drugs. This symptom is often a critical clue in medical diagnoses.

Mydriasis due to LSD usage

Introduction

Mydriasis is characterized by an abnormal expansion of the pupils, which may affect one eye (unilateral mydriasis) or both eyes (bilateral mydriasis). The dilation of the pupil is governed by the balance between the actions of the sphincter pupillae muscle and the dilator pupillae muscle.

Causes

Mydriasis can occur as a result of various underlying causes. These include exposure to certain drugs (such as atropine, antihistamines, and cocaine), trauma, brain injury, eye or nerve disorders, and certain diseases, such as botulism. It is also seen in certain eye examinations where tropicamide or phenylephrine is used to deliberately induce the condition for a better view of the retina.

Symptoms

The most apparent symptom of mydriasis is the noticeable dilation of the pupil(s). However, associated symptoms can occur depending on the underlying cause. These can include light sensitivity (photophobia), blurred vision, headache, or double vision (diplopia).

Diagnosis

Mydriasis is typically diagnosed through a physical examination, particularly an eye examination, which can involve visual acuity testing, a slit lamp examination, and a fundoscopic examination. The doctor may inquire about the patient's medical history, symptoms, and any possible exposures to causative factors.

Treatment

The treatment of mydriasis primarily involves addressing the underlying cause. For example, if a specific medication is causing the dilation, the solution may involve reducing the dosage or switching medications. In certain cases, if the dilation is not harming the patient's vision and does not signify a severe underlying condition, treatment might not be necessary.

Prognosis

The prognosis for mydriasis greatly depends on its cause. If the underlying condition can be successfully treated or managed, the mydriasis will typically resolve. In some cases, however, long-term dilation may persist.

References

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• Wall M. Idiopathic intracranial hypertension. Neurol Clin. 2010;28(3):593-617.
• Pula JH, Kwan K, Yuen CA, Kattah JC. Update on the evaluation of transient vision loss. Clin Ophthalmol. 2016;10:297-303.

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