Anisocoria

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Anisocoria refers to pupils of unequal size, but it is important to note that pupils can differ in size up to 1mm or 0.05 inches.

Babies are sometimes born with unequally sized pupils but this does not denote an underlying disorder. The cause may be genetic and not anything to worry about. But unequal pupils of more than 1mm, that occur in later life and do not return to normal, could be an indication of blood vessel, brain or nerve disease.

What are the causes of Anisocoria?

• Eyedrops can cause a harmless change in pupil size.
• Internal hemmorrhage in the skull through a head injury.
• Glaucoma causing greater pressure in one eye.
• Membranous infection in the brain through meningitis or encephalitis.
• Seizures
• Aneurysms
• A brain tumor or abscess.
• Migraine headaches
• Tumor or lymph node in the upper chest pressing against a nerve.

It is important to see your ophthalmologist if you note a persisting difference in the size of your pupils as it may indicate a serious underlying condition. If the unequal pupil size occurs with any of the conditions below, seek medical advice immediately:

• Double vision
• Fever
• Vision loss
• Eye pain
• Blurred vision
• Light sensitivity
• Headache
• Nausea or vomiting
• Stiff neck

Various diagnostic tests may be carried out to pinpoint the cause and treatment by the ophthalmologist will be prescribed accordingly.