The Effect of Bilateral Medial Rectus Resection for Recurrent Intermittent Exotropia

Sae Rom Chung; Tae Eun Lee; In Cheon You; Nam Chun Cho; Min Ahn

doi:10.3341/jkos.2018.59.6.577

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Chung, Lee, You, Cho, and Ahn: The Effect of Bilateral Medial Rectus Resection for Recurrent Intermittent Exotropia

Original Article

Journal of the Korean Ophthalmological Society 2018; 59(6): 577-581.

Published online: 15 June 2018

DOI: https://doi.org/10.3341/jkos.2018.59.6.577

The Effect of Bilateral Medial Rectus Resection for Recurrent Intermittent Exotropia

Sae Rom Chung, MD¹, Tae Eun Lee, MD^1,^2,³, In Cheon You, MD, PhD^1,^2,³, Nam Chun Cho, MD, PhD^1,^2,³, Min Ahn, MD, PhD^1,^2,³

¹Department of Ophthalmology, Chonbuk National University Medical School, Jeonju, Korea.

²Research Institute of Clinical Medicine, Chonbuk National University, Jeonju, Korea.

³Biomedical Research Institute, Chonbuk National University Hospital, Jeonju, Korea.

Address reprint requests to Min Ahn, MD, PhD. Department of Ophthalmology, Chonbuk National University Hospital, #20 Geonji-ro Deokjin-gu, Jeonju 54907, Korea. Tel: 82-63-250-1960, Fax: 82-63-250-1960, ahnmin@jbnu.ac.kr

Received 28 December 2017 Revised 2 April 2018 Accepted 26 May 2018

The Korean Ophthalmological Society

(open-access):

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

The purpose of this study was to investigate the effect of bilateral medial rectus muscle resection on the treatment of recurrent intermittent exotropia.

Methods

A retrospective chart analysis was conducted for 25 patients who underwent bilateral medial rectus resection for recurrent exotropia over 20 prism diopters (PD) between January 2009 and August 2015. The medial rectus was resected from 4.0 to 6.5 mm by 0.5 mm according to the deviation angle. The postoperative angle of deviation was checked at 1 day, 1 week, 3 months, 6 months, and 1 year postoperatively to investigate the amount of corrected deviation per resected muscle.

Results

The average preoperative deviation angle was 27.20 ± 5.02 PD exodeviation and the mean resection was 5.10 ± 0.79 mm of the medial rectus. The postoperative angle deviation was 10.68 ± 5.50 PD esodeviation at 1 day. The incidence of esodeviation tended to decrease over time. At 1 year, the postoperative angle deviation was 1.16 ± 7.54 PD esodeviation. The overcorrection rate was 84% at 1 day postoperatively but decreased to 24% at 1 year with a success rate of 68%. The corrected deviation angle per millimeter was 7.53 ± 1.22, 7.75 ± 2.16, 6.27 ± 1.74, 5.50 ± 1.54, and 5.56 ± 1.58 PD/mm at 1 day, 1 week, 3 months, 6 months, and 1 year after surgery, respectively. The dose effect per millimeter decreased over time. The corrected deviated angle per millimeter remained constant regardless of the amount of medial rectus muscle resection at 1 year postoperatively(p=0.939).

Conclusions

Bilateral medial rectus resection for recurrent exotropia over 20 PD tended to overcorrect at first; however, after 1 year, the mean angle of deviation was 1.16 ± 7.54 PD esodeviation. Bilateral medial rectus resection is an effective surgical method for the treatment of recurrent exotropia over 20 PD.

Keywords: Bilateral lateral rectus recession, Bilateral medial rectus resection, Recurrent exotropia

Figures and Tables

Figure 1

Surgical outcome of bimedial rectus resection with the course of time. The overcorrection rate decreased to 24% and the success rate increased to 68% at 1 year after bilateral medial rectus resection. ^*Success was defined as distant deviation in the primary position between 10 PD of exodeviation and 5 PD of esodeviation; ^†Overcorrection was defined as distant deviation in the primary position over 5 PD of esodeviation; ^‡Undercorrection was defined as distant deviation in the primary position over 10 PD of exodeviation.

Table 1

Characteristics of patients

Values are presented as mean ± SD unless otherwise indicated.

PD = prism diopters.

Table 2

Change of deviation after operation

Values are presented as mean ± SD.

PD = prism diopters; POD = postoperative day.

^*Esodeviation; ^†Exodeviation.

Table 3

Change of postoperative deviation per a millimeter according to the length of bimedial rectus resection

Values are presented as mean ± SD unless otherwise indicated.

^*Pearson's correlation; r = −0.016, p = 0.939.

Notes

^{Conflicts of Interest} The authors have no conflicts to disclose.

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