# 2021 trends in the treatment of patients with strabismus in Japan

## TL;DR

This study examines how strabismus was treated in Japan in 2021, showing that surgery and botulinum toxin therapy were used, with some regional and age-related patterns.

## Contribution

The study provides updated data on strabismus treatment trends in Japan, including the use of botulinum toxin therapy and surgical practices.

## Key findings

- Strabismus surgery or botulinum toxin therapy was performed at 49% of surveyed institutions in Japan in 2021.
- Exotropia was the most common type of strabismus treated, and most botulinum toxin treatments were concentrated in a single institution.
- Over 48% of patients treated were aged 20 or older, indicating a broader age range for treatment than previously thought.

## Abstract

To clarify the actual status of strabismus surgery and botulinum toxin (BTX) therapy in Japan in the year 2021.

Cross-sectional study.

We conducted a national survey of strabismus treatment in 2021 using a questionnaire consistent with a previous 2013 survey, incorporating additional questions about BTX therapy.

Among the 378 responding institutions, strabismus surgery or BTX therapy, or both, was performed at 185 institutions (49%; total cases, 10,767). In 151 (40%), 32 (8%), and 2 (1%) institutions, surgery only, surgery and BTX therapy, and BTX therapy only were performed, respectively. The distribution of institutions where strabismus surgery was performed consisted of 4 prefectures, accounting for 48% of the total, whereas no strabismus surgery was performed at any institution in 3 prefectures. Although the highest percentage of patients (23%) was aged between 10 and 19 years, 48.2% of the patients were aged 20 years or older, and 17% of them were aged 60 years or older. Exotropia (XT) was the most common type of strabismus (55%) followed by esotropia (ET) (24%). In terms of complex surgeries, 80.2% (more than 100 cases) were performed at institutions with more than 100 cases. Of the 34 institutions where BTX therapy was performed, 52% were performed at a single institution, and 18% were performed at 2 institutions where no strabismus surgery was performed. Patients with scarring in the extraocular muscles, such as thyroid eye disease, were the most treated, followed by those with ET, who were mainly given injection treatment.

Institutions where strabismus surgery and BTX therapy could be performed were concentrated and limited.

The online version contains supplementary material available at 10.1007/s10384-024-01144-5.