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    By John D. Ferris, FRCOphth
    Squint Clinic
    Strabismus

    Botulinum toxin injections into the inner muscles of both eyes is an alternative to surgery, that can be used in children from the age of 3 months of age. This treatment is carried out under a short anesthetic.

    The aim of the treatment is to temporarily weaken the inner muscles of both eyes causing the eyes to drift outwards. As the Botox wears off the child’s eyes will then drift to a straight position. At this point three possible outcomes can occur:

    • The child rediscovers 3D vision and uses it to help keep the eyes in a straight position and no further treatment is needed.
    • The child’s eyes continue to drift inwards, but not as far as they had done before treatment.
    • The child’s eyes return to their original in turned position.

    In the second and third scenario further Botox treatment could be considered. On average, 2 treatments are required to successfully reduce the angle of the strabismus.

    Possible complications of botulinum toxin treatment are:

    • Botulinum toxin may cause a temporary weakness of the eyelid muscles, causing them to become slightly droopy. This may last for up to 2-3 weeks, but fortunately it very rarely affects the child’s vision.
    • If treatment does not permanently reduce the angle of the strabismus, strabismus surgery can still be carried out.

    Following surgery or treatment, children will be followed regularly in the orthoptic clinic to monitor their vision, ocular alignment, and binocular vision. Children will also have periodic spectacle checks to make sure they do not require glasses.

    Amblyopia can occasionally develop following surgery and this will require patching treatment.

    If the child has a developed some form of binocular vision, there is a good chance good ocular alignment will be maintained throughout life. However binocular vision is poor or absent, there is a risk the eyes may eventually drift outwards or inwards. Should this occur, further surgery to straighten the eyes can be undertaken. Forty percent of children with infantile esotropia require more than one operation during their childhood.

    Republished, with permission, from www.squintclinic.com