Characteristics and surgical outcomes of consecutive exotropia of different etiologies

Evaluation of the insertion distance of the medial rectus in consecutive exotropia by means of intraoperative measure and optical coherence tomography

PURPOSE

To assess the agreement between the measurements of the distance from the medial rectus muscles insertion to the limbus measured by intra-operative spectral-domain optical coherence tomography (SD-OCT) in consecutive exotropia (cXT).

METHODS

An analysis was performed on total of 14 medial rectus (MR) muscles of 14 patients who underwent surgery for the treatment of cXT. The limbus-insertion distance of the MR muscles was measured using preoperative SD-OCT and intraoperatively using a calliper. The intraclass correlation coefficient (ICC) and Bland Altman plots were calculated to determine the agreement between the two methods, as well as the correlation.

RESULTS

Mean age was 36.3 ± 16.0 years (range 13-60), with 60% being women. Mean preoperative deviation was 38.7 ± 16.9 prismatic dioptres (PD) (range 16-65), being +1.3 ± 6.3 PD (range -12 to +10 PD) after surgery. Intraoperatively the MR insertion was found at 8.7 ± 2.1 mm (range 5.5-12.0) and by OCT at 7.7 ± 1.2 mm (range 5.3-10.0). The ICC showed a moderate to good agreement (0.659; 95% confidence interval: 0.157-0.885; p < 0.001), with a correlation of R = 0.792 (p = 0.011). A better agreement was observed in those MR that were less retro-inserted.

CONCLUSIONS

SD-OCT is able to measure the insertion to the limbus distance of the medial rectus muscles that have been previously operated on, showing moderate to good agreement with intraoperative measurements. However, the agreement was poor in muscles with a large retro-insertion.

Surgical treatment of consecutive exotropia: Comparison of different surgical methods applied to one eye in one session

PURPOSE

To compare the different surgical methods performed on a single eye in a single session and the factors that affect the success of patients having consecutive exotropia (XT) developed after esotropia surgery.

METHODS

The medical data of the patients who underwent surgery for consecutive XT were reviewed retrospectively. Patients with followed of 6 months or more were divided into four groups; patients with medial rectus (MR) advancement (Group 1 = 10), MR advancement and MR resection (Group 2 = 12), MR advancement and lateral rectus (LR) recession (Group 3 = 13), MR advancement, MR resection, and LR recession (Group 4 = 14). Success results and possible risk factors were investigated.

RESULTS

Forty-nine patients with consecutive XT (21 female, 28 male) were enrolled in the study. The mean age of overall patients was 22.97 years at surgery for consecutive XT. The groups did not display significant differences in terms of surgery ages, gender, refraction values, visual acuity, amblyopia, inferior oblique overaction, limitation of adduction, surgical success rates, and follow-up time (p > 0.05). Patients of Group 4 had larger preoperative and postoperative deviation, while Group 1 had smaller (p < 0.05). The surgical success rates of Groups 1, 2, 3, 4 were 90%, 75%, 76.9%, and 50%, respectively (p = 0.192). Statistically, no factor was found to be effective in surgical success rates (p > 0.05).

CONCLUSION

Surgical treatment of consecutive XT is successful in most of the patients with numerous surgical options performed on a single eye in a single session. Patients, particularly with a high amount of deviation should be warned about the possibility of additional surgery.

Augmented Lateral Rectus Recession for Consecutive Exotropia

Purpose: To evaluate the efficacy of augmented bilateral lateral rectus recession in the treatment of consecutive exotropia.Methods: We retrospectively reviewed records of nine patients who underwent augmented bilateral lateral rectus recession for consecutive exotropia with minimal adduction deficits. Our normal surgical dosing tables for bilateral lateral rectus recession were augmented by adding 1.5-2 mm. All patients had been measured preoperatively using prism and alternate cover testing (PACT), except for one patient in whom Krimsky measurements were performed because of amblyopia. Surgery was deemed successful if postoperative alignment fell within a potential monofixation range of ±10 prism diopters (PD) by PACT at the final postoperative examination.Results: Eight out of nine patients (89%) had a successful outcome. One patient was surgically undercorrected. Despite successful realignment to a state of monofixation syndrome in most patients, there was no significant restoration of stereopsis following strabismus surgery.Conclusions: Surgical augmentation of bilateral lateral rectus recession standard dosing by 1.5-2 mm is efficacious for restoring binocular alignment for both distance and near fixation. This surgical approach may be preferable to bimedial advancements in patients with minimal preoperative adduction deficits who show no significant increase in exotropia during near fixation.

Surgical management of consecutive exotropia: Long-term outcomes

PURPOSE

To compare lateral rectus recession (LRc) and medial rectus advancement (MRadv) for correction of consecutive exotropia (CXT).

METHODS

Of the 43 exotropic patients 20 of them underwent LRc (group 1) and 23 of them underwent MRadv (group 2). Postoperative exodrift, strabismic angle, dose effect relationship were compared with minimum 2 years follow‑up.

RESULTS

An average dose-effect in group 2 is higher than group 1 in the early postoperative period, however there was no significant difference at the second year follow-up (p=0,109). An average exodrift after 2 year follow-up was 6,6±7,12 PD in group 1, and 8,13±7,45 PD in group 2. Postoperative overall success rate was 50% in group 1 and 65% in group 2 at the last follow-up. The success rates were not significantly different between the groups (chi-square, p =0.31).

CONCLUSION

Although there was no statistically significant difference at the last follow-up, better results were obtained with MRadv than LRc in the treatment of CXT.

Management of consecutive exotropia

Purpose:

To determine the clinical characteristics and surgical outcomes of medial rectus (MR) advancement with or without lateral rectus (LR) recession in patients with consecutive exotropia.

Methods:

This interventional case series was performed on patients with consecutive exotropia of more than 15 prism diopters (PD) at least 6 months after the esotropia surgery. All patients were operated using either unilateral or bilateral MR muscle advancement with or without simultaneous LR recession. Ocular deviation at far and near distances, adduction limitation, and exoshift were investigated at the follow-ups of 1 week, as well as 1, 3, and 6 months after the surgery. Operation was considered successful when the postoperative far deviation was <10 PD.

Results:

Thirty patients were evaluated. The mean amount of MR advancement was 5.69 ± 1.33 mm with the mean dose response of 4.7 ± 3.3 and 4.55 ± 4.01 PD at 3 and 6-month follow-ups, respectively. Success rate was reduced from 93% at week 1 to 73% at month 6 due to postoperative exodrift, especially during the first 3 months. Preoperative exotropia was the only contributing factor in our study.

Conclusions:

MR advancement was an effective surgical method for consecutive exotropia correction, especially in cases with MR underaction. Bilateral MR advancement and/or LR recession are suggested in cases with higher preoperative exodeviation. The presence of postoperative exodrift indicates longer follow-ups for patients.

Evaluation of the insertion distance of the medial rectus in consecutive exotropia by means of intraoperative measure and optical coherence tomography

PURPOSE

To assess the agreement between the intraoperative measurements of the distance from the medial rectus muscles insertion to the limbus and preoperative spectral-domain optical coherence tomography (SD-OCT) in consecutive exotropia (cXT).

METHODS

An analysis was performed on total of 14 medial rectus (MR) muscles of 14 patients who underwent surgery for the treatment of cXT. The limbus-insertion distance of the MR muscles was measured using preoperative SD-OCT and intraoperatively using a calliper. The intraclass correlation coefficient (ICC) and Bland Altman plots were calculated to determine the agreement between the two methods, as well as the correlation.

RESULTS

Mean age was 36.3±16.0 years (range 13-60), with 60% being women. Mean preoperative deviation was 38.7±16.9 prismatic dioptres (PD) (range 16 to 65), being +1.3±6.3 PD (range -12 to +10 PD) after surgery. Intraoperatively the MR insertion was found at 8.7±2.1mm (range 5.5 - 12.0) and by OCT at 7.7±1.2mm (range 5.3 - 10.0). The ICC showed a moderate to good agreement (0.659; 95% confidence interval: 0.157-0.885; P<.001), with a correlation of R=0.792 (P=.011). A better agreement was observed in those MR that were less retro-inserted.

CONCLUSIONS

SD-OCT is able to measure the insertion to the limbus distance of the medial rectus muscles that have been previously operated on, showing moderate to good agreement with intraoperative measurements. However, the agreement was poor in muscles with a large retro-insertion.

Clinical and surgical risk factors for consecutive exotropia

Introduction:

Consecutive exotropia is one of the complications of esotropia surgery. Its prevalence is estimated at 4%–27%. The aim of this study was to identify the risk factors for consecutive exotropia in the aftermath of surgical treatment of esotropia.

Methods:

Seventy-four patients examined in our strabismus consultation for a consecutive exotropia from January 2010 to June 2016 were retrospectively included. The age of onset of esotropia, the presence of amblyopia, the age of esotropia surgery and chosen procedure, the refractive errors, the anomalies of ocular motility, the age of onset of the consecutive exotropia and its angle of deviation were reported. Statistical analyses were performed with Student’s test and Fisher’s exact test.

Results:

Esotropia occurred in 65% of cases before the age of 1 year, was associated with amblyopia in 51%, hyperopia in 55% or anisometropia in 31%. Surgery was performed before the age of 6 years for 55% of the patients and involved for 52% the both medial recti. The angle of deviation of consecutive exotropia was ≤20 prism dioptres (PD) in 39%, 21-40 PD in 39% and ≥ 40 PD in 22%, related to amblyopia (p = 0.028), and to high hypermetropia (p = 0.05).

Discussion:

Amblyopia and hyperopia were the most important risk factors of consecutive exotropia in our series. Early onset esotropia, stereopsis abnormalities, anisometropia, oblique dysfunction, convergence insufficiency appeared but did not reach statistical significance.

Conclusion:

Amblyopia is a major risk factor that should be taken into consideration during surgery of an esotropia.