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Strabismus usually develops during childhood but can occur at any age, affecting nearly four in every 100 adults.1 Strabismus is caused by a lack of coordination between the eyes. As a result, the eyes look in different directions and do not focus at the same time on a single point.2

Risk Factors and Symptoms

Strabismus is a visual defect that results when the eyes do not properly align with each other. One eye may look straight ahead but the other may turn in (“crossed eyes”), out (“wall eyes”), upward, or downward. Left untreated, strabismus can result in serious vision problems.3


Patients with strabismus are generally referred to ophthalmologists for treatment. Strabismus treatment focuses on strengthening the eye muscles to improve alignment and achieve normal vision in both eyes. Glasses and eye exercises may be prescribed. When amblyopia is present (as is often the case in children with strabismus) the “good” eye may be covered with a patch forcing the child to use and train the amblyotic eye. If strengthening techniques are unsuccessful, surgery to reposition the extraocular muscles may be considered. Therapy with BOTOX® (onabotulinumtoxinA) provides a minimally-invasive alternative to surgery for appropriate strabismus patients.3


BOTOX® is a prescription medicine that is injected into muscles and used:

  • to treat increased muscle stiffness in elbow, wrist, and finger muscles with upper limb spasticity in people 18 years and older.
  • to treat the abnormal head position and neck pain that happens with cervical dystonia (CD) in people 16 years and older.
  • to treat certain types of eye muscle problems (strabismus) or abnormal spasm of the eyelids (blepharospasm) in people 12 years and older.

BOTOX® is also injected into the skin to treat the symptoms of severe underarm sweating (severe primary axillary hyperhidrosis) when medicines used on the skin (topical) do not work well enough in people 18 years and older.

It is not known whether BOTOX® is safe or effective for other types of muscle spasms or for severe sweating anywhere other than your armpits.


BOTOX® may cause serious side effects that can be life threatening. Call your doctor or get medical help right away if you have any of these problems any time (hours to weeks) after injection of BOTOX®:

  • Problems swallowing, speaking, or breathing, due to weakening of associated muscles,can be severe and result in loss of life. You are at the highest risk if these problems are pre-existing before injection. Swallowing problems may last for several months.
  • Spread of toxin effects. The effect of botulinum toxin may affect areas away from the injection site and cause serious symptoms including: loss of strength and all-over muscle weakness, double vision, blurred vision and drooping eyelids, hoarseness or change or loss of voice (dysphonia), trouble saying words clearly (dysarthria), loss of bladder control, trouble breathing, trouble swallowing.

There has not been a confirmed serious case of spread of toxin effect away from the injection site when BOTOX® has been used at the recommended dose to treat severe underarm sweating, blepharospasm, or strabismus.

The dose of BOTOX® is not the same as, or comparable to, another botulinum toxin product.

Serious and/or immediate allergic reactions have been reported. These reactions include itchy rash, swelling, and shortness of breath. Tell your doctor or get medical help right away if you experience any such symptoms, further injection of BOTOX® should be discontinued.

Do not take BOTOX® if you: are allergic to any of the ingredients in BOTOX® (see Medication Guide for ingredients); had an allergic reaction to any other botulinum toxin product such as Myobloc® or Dysport®; have a skin infection at the planned injection site.

Tell your doctor about all your muscle or nerve conditions such as amyotrophic lateral sclerosis [ALS or Lou Gehrig’s disease], myasthenia gravis or Lambert-Eaton syndrome as you may be at increased risk of serious side effects including severe dysphagia (difficulty swallowing) and respiratory compromise (difficulty breathing) from typical doses of BOTOX®.

Tell your doctor about all your medical conditions, including if you have: plans to have surgery; had surgery on your face; weakness of forehead muscles, such as trouble raising your eyebrows; drooping eyelids; any other abnormal facial change; are pregnant or plan to become pregnant (It is not known if BOTOX® can harm your unborn baby); are breast-feeding or plan to breastfeed (It is not known if BOTOX® passes into breast milk).

Tell your doctor about all the medicines you take, including prescription and nonprescription medicines, vitamins and herbal products.

BOTOX® may cause loss of strength or general muscle weakness, or vision problems. If this happens, do not drive a car, operate machinery, or do other dangerous activities.

Other side effects of BOTOX® include: dry mouth, discomfort or pain at the injection site, tiredness, headache, neck pain, and eye problems: double vision, blurred vision, decreased eyesight, drooping eyelids, swelling of your eyelids, and dry eyes.

For more information refer to the Medication Guide or talk with your doctor.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit, or call 1-800-FDA-1088.

Please see BOTOX® full Product Information, including Medication Guide.

  1. EyeCare America (A program of the Foundation of the American Academy of Ophthalmology); "Strabismus." Available at: Accessed April 9, 2010.

  2. MedLine Plus. "Strabismus." Available at: Accessed April 9, 2010.

  3. American Optometric Association. Optometric Clinical Practice Guideline: Care of the Patient with Strabismus: Esotropia and Exotropia. St. Louis, MO. 1995:9.

  4. The Merck Manual for Healthcare Professionals: "Strabismus." Available at: Accessed April 9, 2010. Updated June 2007.