The Effect of Unilateral Medial Rectus Muscle Resection in Patients with Recurrent Exotropia

PURPOSE: To investigate the effect of unilateral medial rectus muscle resection for recurrent exotropia after bilateral lateral rectus muscle recession for intermittent exotropia METHODS: A retrospective analysis was made of thirtypatients who underwent unilateral medial rectus resection for recurrent exotropia. All had prior bilateral lateral rectus recession for intermittent exotropia. Data were collected for age, the preoperative deviation, the postoperative deviation at 2 weeks, 3 months, 6 months and the last visit, and the amount of medial rectus resection performed. RESULTS: The average preoperative deviation was 27.0+/-3.6 PD. After unilateral medial rectus resection, average deviation at distance was 2.8 PD at postoperative 2 weeks, 4.5 PD at 3 months, 5.1 PD at 6 months and 5.8 PD at last visit. The average deviation corrected per millimeter of medial rectus resection was 3.53+/-0.17 PD/mm. CONCLUSIONS: Considering that deviation angles of recurrent exotropia is smaller than those of primary surgery and the possibility of saving the other medial rectus muscle, unilateral rectus muscle resection could be effective surgical method for recurrent exotropia.

A Case of Convergent Strabismus Fixus with Invisible Cornea

PURPOSE: We report an example of successful operation of rare convergent strabismus fixus, which had previously been mistaken for orbital tumor in private clinics because of severe adduction with unseen cornea. METHODS: A 57-year-old woman had convergent strabismus fixus with inward deviation of the left eye that had gradually progressed since she was around 40. Her cornea was buried in the intraorbital rim. An eye movement examination revealed that the eyeball was fixed to the internal part and that eyeball movement was impossible in all directions. When the forced duction test was performed, strong resistance was shown in all directions when abducted. During surgery, the medial rectus muscle was disinserted after resection of 3.0 mm for the left eye, and lateral rectus muscle tucking of 11.0 mm for the left eye was conducted. Since there was resistance in the inferior oblique muscle by the forced duction test during the operation, inferior oblique muscle myectomy of 4.0 mm was simultaneously performed. RESULTS: In the forced duction test implemented immediately after the operation, resistance subsided considerably and eye movement was shown in all directions, with cosmetically satisfactory results. Optic atrophy was found in the fundus examination after the operation. CONCLUSIONS: Convergent strabismus fixus, which recurs frequently and causes severe limitation of eye movement, was changed from the primary position to orthophoria by medial rectus muscle resection with disinsertion and lateral rectus muscle tucking. The eye movement disorder was improved and a satisfactory result was obtained.

The Clinical Analysis of Surgical Methods in Intermittent Exotropia

PURPOSE: The outcome after operations for intermittent exotropia were frequently unsatisfactory because of high incidence of postoperative undercorrection, overcorrection or recurrence. The author studied surgical outcome of each operation method in intermittent exotropia. METHODS: The results of surgical treatment in 90 patients with intermittent exotropia were reviewed. The operative procedure were devided into 3 groups-bilateral rectus muscle recessions, unilateral lateral rectus muscle recession and medial rectus muscle resection and medial rectus muscle resection of dominant eye and lateral rectus muscle recession of non-dominant eye. The success of operation was defined as a final alignment of orthotropia, esotropia less than 5 prism diopter or exotropia less than 10 prism diopter in primary position at postoperative 6 months. RESULTS: The method of of operation in medial rectus muscle resection of dominant eye and lateral rectus muscle recession of non-dominant eye lead to higher success rate than other surgical method (96.7%) and the difference with statistically significant (p=0.03). The success rate of bilateral rectus muscle recessions group was 76.6%, and that of unilateral lateral rectus muscle recession and medial rectus muscle resection group was 80.0%. CONCLUSIONS: This result suggested that medial rectus muscle resection of dominant eye and lateral rectus muscle recession of non-dominant eye might be a most effective surgical method for intermittent exotropia.

The Surgical Results of Medial Rectus Muscle Resection of Dominant Eye and Lateral Rectus Muscle Recession of Non-dominant Eye in Intermittent Exotropia

Intermittent Exotropia has been treated by various surgical methods such as bilateral medial rectus resection, lateral rectus recession and medial rectus resection of deviating eye, and bilateral lateral rectus recession. However, the outcomes of such operations are unsatisfactory because of high incidence of postoperative undercorrection and overcorrection. Authors have performed a surgical method which is the medial rectus muscle resection of dominant eye and lateral rectus muscle recession of non-dominant eye in 68 patients. Authors considered the outcome successful if patients achieve deviation between 10 PD of exophoria and 5 PD of esophoria, good stereopsis, no suppression and no manifest deviation. The success rate was 83.8% (57/68) and there was no overcorrection over 6 months follow-up. As postoperative complications, 5 cases of temporary turning of face and 3 cases of asymmetric palpebral fissure were seen. Therefore, these results suggest that medial rectus resection of dominant eye and lateral rectus recession of non-dominant eye in intermittent exotropia may be an alternative surgical method for intermittent exotropia. However, further studies are necessary to determine the exact surgical amounts and mechanism of this surgical method.