Anisocoria: Unequal Pupils-Cause for Concern?

Baltimore Washington Eye Center, Maryland

Thursday, November 15, 2012

Anisocoria: Unequal Pupils-Cause for Concern?

Is Anisocoria or unequal pupil size a cause for concern? It may be said that the eyes are the window to the soul, but to get there, one must go thru the pupil first. The pupil can tell us a lot about different types of diseases, both ocular and systemic. Pupil size, shape, reactions to light, dark, and different medications each provide information that our doctors can use to determine what, if anything, might be wrong with a person.

When a person’s pupils are of different sizes, this is called anisocoria. Anisocoria has a number of causes, ranging from benign to life threatening. It has been estimated that 1 in 5 people in the US have what we call physiologic (normal) anisocoria. Other conditions that cause anisocoria include migraines and cluster headaches, trauma, ocular inflammation (either previous or current), multiple sclerosis, ischemic optic neuropathy, significant retinal disease, certain eye drops, certain medications (i.e. inhalers), and certain chemical substances that get placed in the eye from the fingers. Serious conditions that can cause unequal pupils include oculomotor cranial nerve palsy and a dissecting carotid artery aneurysm.

The nerves that cause your pupils to constrict exit from the midbrain, travel just beneath the brain, enter the orbit and continue on to the eye and ultimately the pupil. The nerves that cause your pupils to dilate have a much longer course, starting in the brain, coursing downward thru the spine, exiting in the superior thorax, and traveling back up to the eye following the course of certain blood vessels. Anywhere along these pathways, the nerves can be injured by any number of disease process and/or trauma.

Often times a patient with anisocoria has no other signs or symptoms associated with their anisocoria. Sometimes, patients may have other symptoms such as lid droop, headache, increased light sensitivity (photophobia), double vision, decreased vision, restricted or diminished eye movement, bulging of the eye(s), or pain with eye movement. Not uncommonly, anisocoria is noticed during routine examination in a patient who has no complaints.

Old pictures, i.e. a driver’s license can help to determine how long anisocoria has been present. Depending upon the suspected underlying cause, blood tests, imaging studies (MRI), and certain pharmacologic tests can be performed. Drugs like cocaine can be used to help further define the reason for anisocoria in a given patient.

Fortunately, very often anisocoria is transient and harmless. However, if you notice for the first time different sized pupils and this lasts for more than 24 hrs, or it resolves only to recur, you should have your eyes examined by your local eye care professional to ensure that nothing more worrisome is causing the pupils to be different sizes.

If you or someone you know is concerned about Anisocoria they are encouraged to schedule an eye examination at Baltimore Washington Eye Center by calling 800-495-3937, visiting Baltimore Washington Eye Center or, so that we can help identify the possible causes and recommend an appropriate treatment plan.

Baltimore Washington Eye Center is a leading eye care practice serving the greater Baltimore and Washington, D.C. area staffed by a team of Ophthalmologists, Optometrists, Opticians, technical and administrative staff who provide eye examinations for adults and children, diagnosis and treatment of cataracts including cataract surgery and intraocular lens implants (IOL), laser vision correction such as LASIK, diagnosis and treatment of cornea disease, care for diseases of the retina including diabetes and age related macular degeneration (AMD) and diagnosis and treatment of glaucoma as well as contact lenses, eyeglasses, eyewear and optical services. Baltimore Washington Eye Center is conveniently located for patients from Arbutus, Carney, Clarksville, Columbia, Dundalk, Edgemere, Essex, Ellicott City, Ferndale, Glen Burnie, Kenwood, Laurel, Linthicum, Lutherville, Millersville, Odenton Owings Mills, Reisterstown, Towson, Parkville, Randallstown, Rivera Beach, Pasadena, Severna Park, South Gate and Woodlawn Maryland.