Botox injections help correct ocular alignment in individuals with strabismus

Administering extraocular muscle injection of botulinum toxin type A (BTXA) to individuals with nonparalytic, nonrestrictive horizontal strabismus yields a high rate of successful motor alignment similar to that achieved with eye muscle surgery, according to the results of a systematic review and meta-analysis.

The meta-analysis included 14 articles describing two randomized trials, three nonrandomized comparative studies, and nine case series with a minimum of 50 patients. All the studies assessed extraocular muscle BTXA injection for initial or repeat treatment of horizontal, nonparalytic, nonrestrictive strabismus with a follow-up duration of at least 6 months.

Evidence quality was graded level II for all five comparative studies and level III for the case series. BTXA injection was associated with relatively consistent successful motor outcomes across four of the five comparative studies at 60 percent, after controlling for differential selection bias in one of the studies.

In the four studies evaluating surgery, rates of successful motor outcomes ranged from 66 percent to 77 percent over a mean follow-up of 23–75 months. These results were comparable to those achieved with BTXA injection.

In one level II study, BTXA injection produced greater success compared with surgery (94 percent vs 72 percent).

The level III BTXA case series revealed higher motor success rates of 87 percent to 89 percent in children treated in two muscles at once. On the other hand, success rates were lower in adults who received single-muscle BTXA injection.

The findings suggest that good alignment may warrant multiple BTXA injections. However, there is no clear evidence whether sensory outcomes in young children are equivalent for BTXA injections versus eye muscle surgery.