Purpose: Botulinum toxin type A (BTX-A) injection has been approved for the effective treatment for strabismus in Japan for five years. However, the therapeutic effects of BTX-A injection in Japanese patients with various type of strabismus remains to be elucidated. The purpose of this study was to evaluate which types of strabismus are the most suitable candidates for BTX-A injection.
Subjects and methods: This study included 163 patients who received BTX-A injections for various types of strabismus at Hyogo College of Medicine Hospital between June 2015 and May 2019. All patients complain of diplopia in primary position. The medical records of the patients were retrospectively analyzed regarding the injection site, the number and dosage of BTX-A injections, complications, and progress. Success was assessed by the disappearance of diplopia and eye position within 10 prism diopter from orthostatic position for at least six months after last injection.
Results: Strabismus types were classified as follows: acquired esotropia in 47 cases, strabismus due to active Graves' ophthalmopathy in 32 cases, abducens nerve palsy in 26 cases, oculomotor nerve palsy in 18 cases, and exotropia in 16 cases. Success rates differed by diagnosis: acquired esotropia 51.1%, Graves' ophthalmopathy 43.8%, exotropia 12.5%, and chronic ocular motor nerve palsies 4.5%.
Conclusions: We often hesitate to make decision of surgery on acquired esotropia and strabismus due to active Graves' ophthalmopathy. For these types of strabismus, BTX-A injection has a chance of success in about half of these patients.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 124: 637-643, 2020.