THE LONG-TERM USE OF BOTULINUM TOXIN FOR ADULT STRABISMUS

Purpose: To characterize patients choosing repeated botulinum toxin in jection as a treatment for their strabismus, and assess their demand f or it over time (up to 8 years). Method: Patients who had undergone at least eight injections were identified and their clinical records ana lyzed for diagnosis, demographic details, and demand for toxin injecti ons with time. To establish any predictive variables, the details for these cases were compared with those of matched controls who had under gone fewer injections. Lastly, a questionnaire was mailed to research patients' views as to the indications and preferences for regular toxi n injection as a method of treatment. Results: Ninety-five patients we re identified (34 men, 61 women; median age 37 years), of whom 35 had consecutive exotropia and 16 had secondary exotropia. Other diagnoses represented were residual and primary deviations, restrictive exotropi as, and oscillopsias. A trend of fewer injections over the attendance period was seen, and the only complication observed was upper lid ptos is in 1% of injections. Cases exhibited similar demographic compositio n to matched controls, but were more likely to have consecutive exotro pia or secondary esotropia as a diagnosis. Univariate analysis showed evidence (p<0.001) of an association between the number of previous op erations and the odds of being a case. No evidence was found that case s and controls lived at differing distances from our hospital. The que stionnaire found that 71% of patients stated appearance as the prime r eason for seeking treatment, and 37% stated simplicity of toxin therap y as their reason for reattendance. Twenty-six percent of the patients were disillusioned with the results of previous surgery and preferred toxin therapy as a means of controlling their symptoms. Conclusion: B otulinum toxin injection is an appropriate long-term treatment for som e strabismus patients who choose not to undergo further surgery. A tre nd toward fewer injections with time was observed, and no adverse effe cts were associated with long-term treatment.