Botulinum alignment for congenital esotropia.

BACKGROUND: Botulinum toxin injection into the medial rectus has been recommended by several investigators as an alternative to incisional surgery for treatment of patients with congenital (essential infantile) esotropia. Currently, there are no published studies demonstrating both the motor and sensory results of congenital esotropic patients aligned by botulinum toxin.

METHODS: The author traveled to two medical centers to personally and objectively examine, with standardized testing methods, 12 patients with congenital esotropia who had been aligned for a minimum of 6 months by the age of 2 years by other investigators. The selected patients had been followed for a minimum of 3 years and were of sufficient maturity to reliably respond to sensory testing. A comparison was made between the author's conclusions about the binocularity results of these patients and the assessment of the treating ophthalmologists.

RESULTS: Only 6 of the 12 patients demonstrated optimum motor alignment to within 10 prism diopters (PD) of orthophoria at the time of the study. A minimum of 1-month (average, 5 months) post-botulinum injection was found to be necessary to establish this alignment. Only three of these six aligned patients could both fuse and demonstrate gross stereopsis without the assistance of compensatory prisms. These results can be contrasted to a previously reported group of surgically aligned cases in which 66 of 90 patients aligned by 2 years of age could both fuse and demonstrate stereopsis, without any use of compensatory prisms.

CONCLUSION: These results must be considered preliminary. However, alignment by botulinum appears to be less effective in establishing evidence for binocularity than incisional surgery in the treatment of congenital esotropia (P < 0.001).