Contralateral Inferior Oblique Muscle Overaction after Unilateral Inferior Oblique Weakening Procedures.

Jang, Jun Won; Kyung, Sung Eun

doi:2015.56.3.413

J Korean Ophthalmol Soc > Volume 56(3); 2015 > Article

Original Article

Journal of the Korean Ophthalmological Society 2015;56(3):413-419.
DOI: https://doi.org/10.3341/jkos.2015.56.3.413 Published online March 15, 2015.

Contralateral Inferior Oblique Muscle Overaction after Unilateral Inferior Oblique Weakening Procedures.

Jun Won Jang, Sung Eun Kyung

Department of Ophthalmology, Dankook University Medical College, Cheonan, Korea. kseeye@hanmail.net

단안 하사근약화술 후 반대안의 하사근기능항진

장준원⋅경성은

단국대학교 의과대학 안과학교실

Abstract

PURPOSE
To investigate the effect of unilateral inferior oblique weakening procedures on contralateral inferior oblique muscle functions and factors that may have an effect on contralateral inferior oblique muscle overaction (IOOA). METHODS: A retrospective chart review was conducted of medical records of 40 patients who underwent unilateral inferior oblique (IO) muscle weakening procedures from 2007 to 2011 and were observed during a follow-up period of more than 6 months. These patients were composed of primary IOOA (4 patients), secondary IOOA due to superior oblique muscle (SO) palsy (21 patients), secondary IOOA due to inferior rectus muscle palsy (1 patient), and dissociated vertical deviation (DVD) accompanied with IOOA (14 patients). Factors that may have an effect on contralateral IOOA after undergoing the operation were assessed. RESULTS: There were 7 patients (17.5%) who had over +2 IOOA after operation. IOOA on contralateral eye was increased from average of +0.00 to average of +0.66 +/- 0.14 in 6 months after operation (p < 0.01). There were no statistically significant differences between preoperative factors and functional changes in contralateral IO muscle. CONCLUSIONS: There were no statistical factors that may have an effect on contralateral IOOA but the possibility of masked SO palsy before performing unilateral IO weakening procedures should be considered. In patients who have unilateral DVD associated with IOOA or small hypertropia, the contralateral IOOA can be more definite after operation; thus caution should be taken before operation.

Key Words: Inferior oblique muscle overaction;Unilateral inferior oblique weakening procedures