Management of strabismus due to orbital myositis

We report on 5 consecutive patients seen at the botulinum toxin clinic at Moorfields Eye Hospital with an ocular motility disorder secondary to orbital myositis. CT scans demonstrated involvement of one or both of the medial recti in the inflammatory process in all 5 patients. In addition 1 patient had involvement of both the lateral recti and the right superior rectus. Two patients had been treated with oral steroids, 3 with non-steroidal anti-inflammatory agents, and 1 with orbital radiotherapy. Prior to toxin injection 3 patients had an esotropia (ranging from 4 delta to 30 delta) and two an exotropia (52 delta and 85 delta). A vertical imbalance was present in 3, and all 5 patients had symptomatic diplopia. A total of six injections were given to 5 patients, 2 of whom later went on to have surgery. Toxin injection reduced the angle of the deviation to less than 10 delta in 4 patients, all of whom are now asymptomatic. The fifth patient has persistent diplopia despite two operations to correct a large exotropia. We discuss the role of botulinum toxin and surgery in the management of strabismus due to orbital myositis.