A Case of Cyclic Esotropia Cured by Botulinum Toxin Injection

Cyclic strabismus is a rare entity, which is characterized by alternating periods of strabismus and orthophoria.The mechanism is not clear but seems to be related to the biological clock. Cyclic esotropia is the most common type. On "strabismic"days,a large-angle esotropia will appear, and the binocular vision is impaired. On "straight"days, orthophoria or microstrabismus will appear and no abnor-mal binocular vision is observed. As a treatment, surgery based on the full amount of heterotropia on the strabismic day,has been successful, but treatment by chemodenervation ith botulinum toxin has not been reported yet. Authors experienced the cyclic esotropia following head trauma by a traffic accident in a 3-year-old boy and tried the injection of botulinum toxin on both medial rectus muscles as a treatment. In one-year follow-up observation, the cyclic pattern and esodeviation has disappeared.

Cyclic Exotropia: One Case of Clinical Report

Cyclic strabismus is now well recognized, but remains a rare entity. This heterotropia represents an interesting ocular motility problem in which the ocular deviation is present on a rhythmic basis, usually a 48 hour cycle. On the strabismic day, constant heterotropia is large and associated with suppression and no diplopia. On the nonstrabismic day, no deviation or only a small heterophoria is present with good binocular function. Most of these strabismus were presented with esotropia, but in our case, the pattern of deviation is cyclic exotropia. This is a very rare and unique feature.