The stability of horizontal ocular alignment of triad exotropia after one-step triple surgery
A-pattern exotropia, superior oblique muscle overaction, and dissociated vertical deviation may coexist and are referred to as triad exotropia. The present study evaluated the postoperative stability of horizontal ocular alignment of triad exotropia and possible prognostic factors.
Medical records of patients with triad exotropia who had one-step triple surgery of superior oblique muscle weakening, superior rectus muscle recession, and lateral rectus muscle recession were reviewed. The horizontal alignment and postoperative drift of triad exotropia were analyzed and compared with constant exotropia.
The triad exotropia showed a mean of 7.7△ (± 8.5△) eso-drift, while the constant exotropia was (3.5△ ± 3.4△) exo-drift. Multiple linear regression analysis showed that the degree of superior oblique muscle overaction after surgery (P = 0.011) was the only factor associated with horizontal drift. Patients with superior oblique muscle underaction showed larger eso-drift when compared to patients without superior oblique muscle underaction (− 18.0△ ± 11.1△ vs. − 5.1△ ± 5.7△; P = 0.024). The final success rates of the triad exotropia and constant exotropia groups were 53.3% and 69.2%, respectively, and the overcorrection rates were 26.7% and 2.6% (P = 0.035).
An overall trend of eso-drift in primary position occurred in triad exotropia after triple surgery up to a follow-up of 25 months. Patients presenting superior oblique muscle underaction after surgery seemed to have large angles of eso-drift, which might be taken into account in surgical planning and follow-up.
KeywordsHorizontal ocular alignment Superior oblique muscle weakening A-pattern exotropia Superior oblique muscle overaction Dissociated vertical deviation
This study was funded by the National Natural Science Foundation of China (Grant No. 81600765); the Foundation of Shanghai Municipal Commission of Health and Family Planning (Project No. 201640120); Shanghai Outstanding Academic Leaders (2017BR013); and Excellent Academic Leaders of Shanghai (18XD1401000).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional review board of Eye and ENT Hospital, Fudan University and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
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