What are the other Names for this Condition? (Also known as/Synonyms)

• MA (Mechanical Anisocoria)

What is Mechanical Anisocoria? (Definition/Background Information)

• Anisocoria is a relatively common eye condition that is characterized by “unequal pupil sizes”. In other words, the size of the left and right pupils vary in dimension (different sizes). Based on the underlying cause, anisocoria is classified into several types
• Mechanical Anisocoria (MA) is typically described as an acquired condition that develops following eye trauma or inflammatory conditions that damage the iris and other eye structures

Who gets Mechanical Anisocoria? (Age and Sex Distribution)

• Anisocoria is reportedly common among the general population
• Individuals of any age category (both children and adults) may be affected by Mechanical Anisocoria
• Both males and females may be affected
• Worldwide, individuals of all races and ethnicity are prone to developing the condition

What are the Risk Factors for Mechanical Anisocoria? (Predisposing Factors)

The risk factors for Mechanical Anisocoria may include:

• Trauma to the eye
• Ocular surgery
• Inflammatory eye conditions such as iritis and uveitis
• Tumors of the eye
• Angle closure glaucoma

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Mechanical Anisocoria? (Etiology)

• Anisocoria occurs due to damage or abnormal functioning of the nerves that control the pupil sizes; this results in unequally sized pupils
• Mechanical Anisocoria is an acquired form of anisocoria that develops following an eye injury, tumor, or inflammatory disorder which damages the iris and other structures

What are the Signs and Symptoms of Mechanical Anisocoria?

The characteristic feature of all forms of anisocoria is the difference in pupil sizes. The signs and symptoms of Mechanical Anisocoria may vary from one individual to another. It depends on several factors, such as the severity of the condition and underlying causative factors.

The signs and symptoms of Mechanical Anisocoria may include:

• Light sensitivity and glare from pupil dilation (mydriasis)
• Impaired accommodation
• Eye pain
• Headache
• Double vision
• Blurry vision
• Fatigue
• Numbness
• Droopy eyelids
• Impaired coordination or ataxia

Associated signs and symptoms of the underlying condition/disorder may also be observed.

How is Mechanical Anisocoria Diagnosed?

Mechanical Anisocoria may be diagnosed by the following observations and tests:

• Physical examination and medical history evaluation (including evaluating for any history of eye injury, surgery, or lesions)
• Assessment of signs and symptoms
• General eye exam:
  • Examination of the eye in both dark and lighted environments
  • Using topical eye drops to determine the pupillary size reaction is also helpful in arriving at possible cause
• Blood and urine tests to diagnose underlying conditions/disorders, as necessary
• Fundoscopic (ophthalmoscopic) examination by an eye specialist, who examines the back part of the eye (or the fundus)
• Visual acuity test using a special and standardized test chart (Snellen chart)
• Slit-lamp examination
• Visual evoked potential (VEP) test
• Fundus fluorescein angiography
• Optical coherence tomography (OCT) of eye
• Imaging studies including CT and MRI scans of the head and neck region

Additional tests and procedures to diagnose the underlying causative condition may be needed.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Mechanical Anisocoria?

The complications of Mechanical Anisocoria may include:

• Difficulty in performing simple tasks under bright lights
• Vision impairment
• Decreased quality of life
• Treatment related complications

Complications arising from the underlying/associated condition, if any, may be noted.

How is Mechanical Anisocoria Treated?

The treatment of Mechanical Anisocoria depends on its severity, the presenting signs and symptoms, and the underlying causative factor.

• The treatment measures include treating the symptoms and managing the underlying condition/disorder
• Mechanical Anisocoria due to structural defects may be corrected using surgery
• If it is caused by underlying medical conditions, such as glaucoma or uveitis, it may be treated using medications

How can Mechanical Anisocoria be Prevented?

It may be difficult to prevent some cases of Mechanical Anisocoria. However, the following factors may help reduce one’s risk for developing the same:

• Undertaking early and adequate treatment of any health issues, such as glaucoma, uveitis, or eye lesions, is important
• Wear helmets and safety gear while participating in sports or while driving to prevent head/eye injury

What is the Prognosis of Mechanical Anisocoria? (Outcomes/Resolutions)

The overall prognosis of Mechanical Anisocoria depends on the underlying cause, severity of presenting signs and symptoms, age, and the individual’s response to treatment measures.

Additional and Relevant Useful Information for Anisocoria:

Please visit our Eye & Vision Health Center for more physician-approved health information:

https://www.dovemed.com/health-topics/vision-center/