Bilateral vs unilateral medial rectus resection for recurrent exotropia after bilateral lateral rectus recession

Long-term surgical outcomes of one-muscle vs. two-muscle horizontal strabismus surgery

PURPOSE

While horizontal strabismus surgery is generally considered to have favorable outcomes, success rates can vary by type of procedure. Our purpose is to compare the long-term outcomes of patients who underwent one-muscle vs. two-muscle horizontal strabismus surgery.

METHODS

This is a retrospective study comparing one-muscle to two-muscle strabismus surgery for small to moderate angle horizontal strabismus. Demographic data and eye exam parameters were compared at baseline and postoperatively (6 months up to 6 years). Surgical success was defined as a post-operative angle of 10 PD or less. We also compared outcomes by strabismus type: esotropia vs exotropia and adjusted the analysis for previous strabismus surgery.

RESULTS

Out of 89 patients with moderate angle horizontal strabismus (25 PD or less), 17 patients had a one-muscle operation, and 72 patients had two-muscle surgery. The mean age was 14.12 ± 9.30 years and 11.70 ± 11.30 years for the one-muscle and two-muscle groups, respectively (p = .74). The baseline characteristics of both groups were comparable. Follow-up time was 32.82 ± 26.93 months in one-muscle and 37.67 ± 23.81 in two-muscle groups (p = .29). Success rate was 70.6% for the one-muscle group and 68.10% for the two-muscle group (p = .69). Outcomes were similar when divided into esotropia and exotropia. The success rate was not affected by previous strabismus surgeries nor by the initial angle of deviation.

CONCLUSION

One-muscle and two-muscle horizontal strabismus surgery had similar long-term outcomes and did not differ by strabismus type nor by angle of deviation.

Study on the postoperative visual function recovery of children with concomitant exotropia based on an augmented reality plasticity model

Objective

This study aimed to investigate the clinical application effect of an augmented reality (AR) plasticity model on the postoperative visual function recovery of children with concomitant exotropia.

Methods

Between September 2019 and October 2021, 28 patients with concomitant exotropia who visited Shenzhen Children's Hospital (9 male and 19 female) were enrolled in this study. The average age of the patients was 6.4 ± 1.8 years. Postoperative rehabilitation training was conducted using a personalized AR binocular visual perception plasticity model developed based on the patient's examination results. After 1 month, 3 months, and 6 months of training, the patients returned to the hospital for examinations of perceptual eye position, static zero-order stereopsis, dynamic first-order fine stereopsis, and dynamic second-order coarse stereopsis to compare the changes in eye position control and stereovision function.

Results

After 6 months of eye position training, the horizontal perception eye position of the 28 patients was significantly lower than that before training. The difference in eye position at the first and third months compared with that before training was not statistically significant (1st month: z = -2.255, p = 0.024 > 0.017; 3rd month: z = -2.277, p = 0.023 > 0.017; 6th month: z = -3.051, p = 0.002 < 0.017). The difference in vertical perceptual eye position after training compared with that before training was not statistically significant (1st month: z = -0.252, p = 0.801 > 0.017; 3rd month: z = -1.189, p = 0.234 > 0.017; 6th month: z = -2.225, p = 0.026 > 0.017). The difference in 0.8-m static zero-order stereopsis before and after training was not statistically significant (1st month: z = -2.111, p = 0.035 > 0.017; 3rd month: z = -1.097, p = 0.273 > 0.017; 6th month: z = -1.653, p = 0.098 > 0.017). The 1.5-m static zero-order stereopsis was improved after 1 month, 3 months, and 6 months of training compared with that before training (1st month: z = -3.134, p = 0.002 < 0.017; 3rd month: z = -2.835, p = 0.005 < 0.017; 6th month: z = -3.096, p = 0.002 < 0.017). Dynamic first-order fine stereopsis and dynamic second-order coarse stereopsis were measured in the 28 patients before and after training. Patients 1 and 18 had no dynamic first-order fine stereopsis before training, but both regained dynamic stereopsis after 1 month, 3 months, and 6 months of training. Patient 16 had no dynamic first-order fine stereopsis or dynamic second-order coarse stereopsis before training, but first-order and second-order stereopsis had been reconstructed after 1 month, 3 months, and 6 months of training.

Conclusion

Concomitant exotropia surgery improved the basic problem of eye position at the ocular muscle level, but the patient's perceptual eye position and visual function defects at the brain visual level remained. This might partly explain the poor postoperative clinical effect. The AR plasticity model can improve patients' horizontal perceptual eye position and multi-dimensional stereoscopic function, and its clinical effect warrants further study.

The Effects of Orthoptic Therapy on the Surgical Outcome in Children with Intermittent Exotropia: Randomised Controlled Clinical Trial

BACKGROUND

To assess the clinical effectiveness of orthoptic therapy in the postoperative stabilisation and rehabilitation of binocular function in children with intermittent exotropia (IXT) after surgery.

METHODS

This was a prospective, parallel, randomised controlled trial. A total of 136 IXT patients (aged from 7 to 17 years) who had been successfully corrected at 1 month after surgery were enrolled in this study, and 117 patients (58 controls) completed the 12-month follow-up visit. The primary outcome was established as the proportion of patients with suboptimal surgical outcomes, which were defined as: (1) exodeviation ≥10 prism diopters (PD) at distance or near using the simultaneous prism and cover test (SPCT), or (2) constant esotropia ≥6 PD at distance or near using SPCT, or (3) loss of 2 or more octaves of stereopsis from baseline. The secondary outcomes were the exodeviation at distance and near using the prism and alternate cover test (PACT), stereopsis, fusional exotropia control and convergence amplitude.

RESULTS

The cumulative probability of suboptimal surgical outcome by 12 months was 20.5% (14/68) in the orthoptic therapy group and 42.6% (29/68) in the control group. There was a significant difference between these two groups (χ² = 7.402, p = 0.007). Improvements in stereopsis, fusional exotropia control and fusional convergence amplitude were found in the orthoptic therapy group. A smaller exodrift was found in the orthoptic therapy group at near fixation (t = 2.26, p = 0.025).

CONCLUSIONS

Early postoperative orthoptic therapy can effectively improve the surgical outcome as well as stereopsis and fusional amplitude.

How to Better Treat Patients with Intermittent Exotropia: A Review of Surgical Treatment of Intermittent Exotropia

Intermittent exotropia (X(T)) is the most common form of strabismus, especially in Asians. Treatment of X(T) includes occlusion, overminus lens, and surgery, of which, surgery is the mainstay of treatment. Commonly performed surgical procedures for X(T) are bilateral lateral rectus muscle recession or unilateral lateral rectus recession with medial rectus resection; however, it is unclear which of the two surgeries is more effective. The purpose of this review is to provide an insight on the surgical treatment of X(T). Randomized controlled trials, comparative observational studies, and case series with a large number of patients as well as a long follow-up period of over a year were included.

Analysis of new attachment site in medial rectus resection with advancement using anterior segment optical coherence tomography

OBJECTIVE

To evaluate the surgical outcome of unilateral medial rectus resection with small advancement for recurrent exotropia, ≤30 prism diopters (PD), and verify new attachment site anatomically using anterior segment optical coherence tomography (ASOCT).

METHOD

This study is a retrospective chart review of patients who underwent 1.0 mm advancement of unilateral resected medial rectus from original medial rectus (OMR) insertion for recurrent exotropia since 2014. The age at operation, sex, preoperative angle of deviation, near stereopsis, and suppression were evaluated. Success was defined as ≤5 PD of esodeviation or ≤10 PD of exodeviation at the final visit. Preoperative scleral thickness was measured using ASOCT, 1.0 and 0.5 mm anterior to OMR insertion, and at the insertion.

RESULTS

A total of 76 patients, including 30 males (40.2%), were reviewed retrospectively. Continuous values were presented as mean ± standard deviation. Age at operation was 11.6 ± 6.6 years. The preoperative deviation was 20.9 ± 3.6 PD, and the amount of resected unilateral medial rectus was 4.5 ± 0.6 mm. The minimum required follow-up period after operation was 12 months after surgery. The postoperative follow-up period was 21.3 ± 8.0 months. A total of 65 patients (87.8%) showed successful outcome at the final visit. Preoperative scleral thickness at 1.0 and 0.5 mm anterior to OMR insertion site, and at OMR insertion site were 0.52 ± 0.05, 0.52 ± 0.06, and 0.43 ± 0.04 mm, respectively. Scleral thickness at OMR insertion site was significantly less compared with 1.0 and 0.5 mm from the OMR insertion site (p = 0.03).

CONCLUSION

The scleral thickness 1.0-0.5 mm anterior to OMR insertion site was thicker that than at the OMR insertion site. The new technique of medial rectus resection with small advancement may be safer and more effective than conventional technique.

Risk factors associated with poor outcome after medial rectus resection for recurrent intermittent exotropia

PURPOSE

To describe characteristics of recurrent intermittent exotropia after bilateral lateral rectus (BLR) recession, and identify factors associated with poor outcome after unilateral medial rectus (MR) resection for recurrent intermittent exotropia.

METHODS

We retrospectively reviewed 124 patients who have undergone unilateral MR resection for recurrent intermittent exotropia after BLR recession. Patients were followed for at least 2 years after MR resection. Clinical characteristics and risk factors associated with poor outcome after unilateral MR resection were evaluated. Successful outcome was defined as distant deviation within the range of 4 prism diopters (PD) esotropia and 10 PD exotropia at last visit after MR resection.

RESULTS

Among 124 patients, 50 patients (41.1%) were male, and the mean age at the time of MR resection was 9.5 ± 3.1 years. The average follow-up period after MR resection was 43.8 ± 23.7 months. Forty-seven patients (37.9%) were classified to have poor outcome at last visit, and 29 patients (23.4%) underwent third operation. None of the patients was overcorrected after MR resection. Multiple logistic regression analyses showed that distant deviation at post-operative 3 months and male gender were associated with poor outcome (OR 1.49; 95% CI 1.27-1.73; P < 0.001, and OR 5.19; 95% CI 1.42-18.98; P = 0.013, respectively).

CONCLUSION

Ocular deviation at 3 months after unilateral MR resection for recurrent intermittent exotropia may play a valuable role in anticipating poor outcome. Patients whose exotropia exceeded 9 PD at distance at 3 months' follow-up tended to recur while those whose exotropia remained below 9 PD at distance showed a stable disease course.

Surgical management of intermittent exotropia: do we have an answer for all?

Intermittent exotropia (X(T)) is one of the most common form of strabismus with surgery being the mainstay of treatment. The main goal of surgery is to preserve binocular vision and stereopsis and to prevent its further loss. The decision to operate is mainly based on four aspects: increasing angle of exodeviation, deteriorating control of X(T), decrease in stereopsis for near or distance and quality of life. Bilateral lateral rectus muscle recession and unilateral lateral rectus recession with medial rectus resection, are the two most common surgical procedures performed and have been studied extensively in basic, divergence excess and convergence insufficiency types of X(T). However, there is no consensus over the relative efficacy of the two procedures in terms of postoperative alignment, residual or recurrent exotropia and consecutive esotropia with widely variable results, which can be attributed to poor understanding of the natural course of the disease. Multiple demographic, clinical and anatomic features that may influence the surgical outcomes have been studied to explain this variability. Moreover, most of the evidence regarding surgical outcomes of X(T) is from retrospective studies and the ongoing randomised prospective trials can shed light on long-term efficacy of these procedures. The goal of this review is to give a comprehensive overview of the outcomes of various surgical techniques in the management of different types of X(T), the preoperative and postoperative factors that may affect the surgical outcomes and to discuss the dilemmas faced by the treating surgeons including the effective management of overcorrection and undercorrection.

Long-term surgical outcomes of bilateral vs. unilateral medial rectus resection for recurrent exotropia

BACKGROUND/OBJECTIVES

The objective of this study is to compare the long-term outcomes of bilateral and unilateral medial rectus (BMR/UMR) resection for recurrent exotropia after bilateral lateral rectus (BLR) recession.

SUBJECTS/METHODS

Retrospective study was performed of 99 patients who underwent BMR resection (BMR group) or UMR resection (UMR group) for recurrent exotropia of 20-30 prism diopters (PD), with a minimum follow-up of 5 years. Surgical outcomes including success rate, exodrift rate, and average effect of MR resection were compared between two groups. The risk factors associated with poor outcomes were evaluated.

RESULTS

At 5 years after surgery, 57% in the BMR group and 62% in the UMR group showed successful outcome. Success and recurrence rates were not significantly different between two groups, whereas the overcorrection rate was significantly higher in the BMR group (35% vs. 15%; p = 0.039). The average effect of MR resection was significantly greater after BMR throughout the whole postoperative period. The average effect of UMR resection was significantly greater in those who had previously undergone a large amount of BLR recession compared with those with a smaller dosage (p = 0.006). By multivariate analysis, a large amount of previous BLR recession and initial overcorrection of >10 PD of esotropia were found to be significant risk factors of overcorrection.

CONCLUSION

In moderate angles of recurrent exotropia, large UMR resection is a safe and efficient procedure. However, if a large BLR recession was performed previously, surgical dosage for UMR resection should be reduced because of the high risk of long-term overcorrection.

Bilateral Lateral Rectus Recession for the Treatment of Recurrent Exotropia after Bilateral Medial Rectus Resection

PURPOSE

To evaluate the efficacy of bilateral lateral rectus muscle recession (BLR) to treat recurrent exotropia after bilateral medial rectus muscle resection (BMR).

METHODS

Twenty-four patients who underwent BLR for recurrent exotropia and were followed up for more than 6 months were included in this retrospective study. All of them had prior BMR. The angle of deviation, success rates, near stereopsis, and surgical effect of BLR were evaluated. Surgical success was defined as postoperative deviations ≤10 prism diopters (PD).

RESULTS

The overall mean follow-up time after reoperation for patients was 24.13 ± 15.01 months (range 6-60 months). The mean angle of deviation at distance was significantly reduced from -37.75 ± 14.93 PD to +1.50 ± 6.43 PD (p < 0.001). Twenty-two (91.6%) of 24 patients had successful outcomes, 1 (4.2%) had overcorrection, and 1 (4.2%) had undercorrection at the last follow-up. Improved stereopsis after reoperation was observed in 78.3% (18/23) of the patients. The mean surgical effect was 2.78 ± 0.71 PD/mm.

CONCLUSION

Based on our results, BLR could be an effective and safe method for treating recurrent exotropia after a moderate to large amount of BMR.

Outcomes of bilateral lateral rectus recession in treatment of recurrent exotropia after bilateral medial rectus resection

PURPOSE

To report the results of bilateral lateral rectus muscle recession for recurrent exotropia in cases where the primary surgery was a bilateral medial rectus resection.

METHODS

Retrospective chart review of 15 subjects who completed 6 months of follow-up. Data collected included patients' demographics and pre- and post-operative measurements of ocular alignment and motility. Surgical nomogram used was the same nomogram we use for primary cases of exotropia.

RESULTS

At 6-month follow-up, 73.3% of cases had a successful surgical outcome (defined as 8 PD of esotropia to 10 PD of exotropia). In addition, recession of lateral rectus muscles against the previously resected medial recti did not result in a significant increase in the limitation of abduction.

CONCLUSION

Bilateral lateral rectus recession using standard surgical tables is a safe and effective method for treating recurrent exotropia following bilateral medial rectus resection. Even large primary resections up to 12 mm do not seem to affect the results of bilateral lateral rectus recession.

One-Muscle Strabismus Surgery: A Review

Proper management of a patient with small to moderate horizontal deviations continues to be challenging for the strabismus surgeon. The use of one-muscle surgery for comitant strabismus has been controversial because of concerns that it may result in a significant number of undercorrections and/or ocular incomitance. Recent literature on unilateral rectus muscle surgery has shown that this surgery is a safe and effective procedure for small and moderate angle horizontal deviations. It has the advantage of limiting surgery to one eye, reducing operative time and possible cost to the family, and leaving other muscles untouched in case repeat surgery is necessary. Larger studies need to be done in the future; however, this surgery should be considered as a primary approach in the treatment of small to moderate angle esotropia. [J Pediatr Ophthalmol Strabismus. 2018;55(5):288-292.].

Reduction of Consecutive Esotropia Using Modified Contralateral Recession and Resection for Recurrent Intermittent Exotropia

PURPOSE

To report consecutive esotropia in contralateral lateral rectus recession and medial rectus resection for recurrent intermittent exotropia after unilateral lateral rectus recession and medial rectus resection and to evaluate the surgical outcome of modified contralateral lateral rectus recession and medial rectus resection for exotropia after unilateral lateral rectus recession and medial rectus resection.

METHODS

A total of 36 patients were included in this retrospective study. As a primary surgery for exotropia, all patients underwent unilateral lateral rectus recession and medial rectus resection on the non-dominant eye. Patients were subsequently assigned to either conventional contralateral lateral rectus recession and medial rectus resection (surgical dosages based on Wright's surgical table) (n = 19; conventional group) or modified contralateral lateral rectus recession and medial rectus resection (surgical dosages reduced by 5 prism diopters on Wright's surgical table) (n = 17; modified group) for recurrent exotropia. Surgical success rates were evaluated. Reoperation or prism glasses prescription rates due to consecutive esotropia were evaluated.

RESULTS

The mean follow-up durations after reoperation were 25.8 and 24.0 months in the conventional and modified groups, respectively. The surgical success rates were 73.7% and 82.4% (P = .538, Fisher's exact test) and the recurrence rates were 0% and 17.6% (P = .059, Fisher's exact test), respectively. The reoperation or prism glasses prescription rates due to consecutive esotropia were 26.3% and 0%, respectively (P = .025, Fisher's exact test).

CONCLUSIONS

Final outcomes were better in the modified group compared to the conventional group. Consecutive esotropia was significantly more frequent in the conventional group than in the modified group. In surgery for recurrent exotropia, a reduction of the surgical dosage will reduce the incidence of consecutive esotropia. [J Pediatr Ophthalmol Strabismus. 2018;55(1):53-58.].

Early postoperative overcorrection in recurrent exotropia

OBJECTIVE

To investigate the surgical outcome according to the angle of deviation at postoperative day 1 in patients with recurrent exotropia DESIGN: Retrospective case series METHODS: Surgical outcome in patients with recurrent exotropia for at least 1 year was analyzed retrospectively. Patients were divided into 3 subgroups according to the angle of deviation at postoperative day 1: overcorrection group (≥2 prism diopter [PD] of esodeviation), orthotropic group (orthotropia or <5 PD of exodeviation), and undercorrection group (≥5 PD of exodeviation). Success was defined as ≤5 PD of esodeviation or ≤10 PD of exodeviation at the final visit.

RESULTS

One hundred and six patients were included in this study. Age at surgery was 11.8 ± 6.9 years, and preoperative angle of deviation was 22.9 ± 6.3 PD at distant. Patients were followed-up for 24.4 ± 12.8 months. There were 20 (18.9%), 82 (77.4%), and 4 (3.8%) patients in overcorrection, orthotropic, and undercorrection groups at postoperative day 1 (p = 0.001). The surgical success rate at the final visit in the overcorrection group (95%) was higher than that in orthotropic and undercorrection groups (76.8% and 25%, respectively, p = 0.004). In univariate regression analysis, overcorrection at postoperative day 1 was the only reliable factor for long-term success (odds ratio [OR] = 24.101, p = 0.01).

CONCLUSION

Overcorrection at postoperative day 1 is a good surgical predictor of successful outcome in surgery for recurrent exotropia.

Goal-determined metrics to assess outcomes of exotropia surgery

PURPOSE

To present a goal-determined methodology for monitoring outcomes after surgery for exotropia.

METHODS

The goal-determined metric required surgeons to rank four possible goals preoperatively: (1) binocular potential, (2) restoration of eye contact, (3) diplopia control; and (4) torticollis management. Potential preoperative risk factors were noted. Goal-specific outcomes criteria were applied to the latest sensory-motor examination, 2-6 months after surgery. The medical records of patients who underwent surgery from 2007 to 2012 were retrospectively reviewed with respect to the goal-directed metric.

RESULTS

A total of 852 patients were evaluated in the study period: 411 for restoration of eye contact; 347 for binocular potential; 78 for diplopia resolution; and16 for torticollis management. Excellent (62%) or good (16%) outcomes were achieved in 78%. Procedures to resolve diplopia (OR, 6.56; 95% CI, 3.39-12.68) and to restore eye contact (OR, 3.74; 95% CI, 2.65-5.29) were more likely to result in excellent outcomes than procedures to improve binocular potential. Simultaneous surgery for dissociated vertical deviation (OR, 0.38; 95% CI, 0.16-0.92) and preoperative near deviation ≥50(Δ) (OR, 0.27; 95% CI, 0.17-0.42) limited likelihood of an excellent outcome. Outcomes monitored by simultaneous rather than alternate prism and cover test were more likely graded excellent (OR, 5.16; 95% CI, 3.50-7.62). Applying motor criteria from the binocular potential goal to the entire cohort diminished putative outcomes (P < 0.001).

CONCLUSIONS

Goal-determined metric monitoring outcomes of exotropia surgery provides outcomes germane to the reason for intervention, enables analysis of risk factors affecting outcomes, and facilitates reporting on heterogeneous populations.

Unilateral medial rectus resection for the treatment of recurrent exotropia in children

PURPOSE

To investigate the outcomes of unilateral medial rectus resection (UMR-res) for the treatment of small to moderate angles of recurrent exotropia in children followed up for a minimum of 6 months.

METHODS

This study is a retrospective, consecutive, interventional case series in which 48 children who underwent UMR-res (range 4.0-7.5 mm) for recurrent exotropia [range 12-25 prism diopters (PD)] between January 2009 and February 2013 were enrolled. Of these 48 children, 32 had recurrent intermittent exotropia, and 16 had recurrent constant exotropia. A successful surgical alignment was defined as +5 to -10 PD of orthophoria in the primary position while viewing distant or near targets.

RESULTS

At a mean follow-up of 12 months, the surgical success rate was 75 % (36/48), and the undercorrection rate was 25 % (12/48). No patient exhibited overcorrection. The success rates of the UMR-res in the recurrent intermittent exotropia group and recurrent constant exotropia group were 78 % and 69 %, respectively, and were not significantly different (P = 0.50). In the initial surgical procedure groups, the success rates of patients with bilateral lateral rectus recession, unilateral lateral rectus recession, and unilateral lateral rectus recession combined with medial rectus resection were 81.8 % (18/22), 81.25 % (13/16), and 50 % (5/10), respectively. The surgical success rates did not differ among these three groups (P = 0.122).

CONCLUSION

Based on our results, UMR-res would appear to be an effective and safe procedure for the treatment of intermittent or constant recurrent exotropia of ≤25 PD in children.

Surgical outcome of medial rectus resection in recurrent exotropia: a novel surgical formula

Purpose. To evaluate the surgical outcomes of unilateral or bilateral medial rectus (MR) muscle resection for recurrent exotropia after bilateral lateral rectus (BLR) muscle recession based on a novel surgical formula. Methods. Forty-one consecutive patients with unilateral or bilateral MR muscle resection for recurrent exotropia after BLR muscle recession were included in this retrospective study. All surgeries were performed according to the formula: 1.0 mm MR muscle resection for every 5 prism dioptres (PD) of exotropia, with an addition of 0.5 mm to each MR muscle operated on. Results. The mean recurrent exotropia distant deviation was 28 PD ± 11.2 (range 14 to 55 PD). Overall at postoperative 1 month, 36 (88%) achieved successful outcomes, 4 (10%) had undercorrection, and 1 (2%) had overcorrection. At postoperative 6 months, 29 (71%) achieved successful outcomes, 12 (29%) had undercorrection, and none had overcorrection. Subgroup analysis showed no statistically significant difference in success rates between unilateral and bilateral MR groups. Conclusion. Unilateral or bilateral MR muscle resection using our surgical formula is a safe and effective method for calculating the amount of MR resection in moderate to large angle recurrent exotropia, with a low overcorrection rate.

Comparison of lateral rectus muscle re-recession and medial rectus muscle resection for treatment of postoperative exotropia

PURPOSE

To compare the outcomes of unilateral lateral rectus muscle re-recession and medial rectus muscle resection for treatment of recurrent or persistent exotropia.

DESIGN

Retrospective nonrandomized clinical trial.

METHODS

setting: Hospital-based clinical practice.

PATIENT POPULATION

Forty patients with recurrent or persistent exotropia following bilateral lateral rectus muscle recessions.

INTERVENTION

Fourteen patients were treated with unilateral medial rectus muscle resection and 26 with unilateral lateral rectus muscle re-recession.

MAIN OUTCOME MEASURES

Outcomes were considered successful if the patients had deviations less than 10 prism diopters (PD) at last follow-up. All patients were followed for at least 1 year postoperatively.

RESULTS

The mean preoperative deviations were 17.4 PD in the medial rectus muscle resection group and 18.1 PD in the lateral rectus muscle re-recession group. Successful outcomes were achieved in 9 of 14 patients (64%) treated with medial rectus muscle resection and 19 of 26 patients (73%) treated with lateral rectus muscle re-recession. There was no statistically significant difference between these outcomes. Mean follow-up was 4.5 years in the medial rectus muscle resection group and 2.9 years in the lateral rectus muscle re-recession group.

CONCLUSIONS

Surgery on a single muscle can be used to treat moderate-angle recurrent or persistent exotropia. Unilateral re-recession of the lateral rectus muscle and medial rectus muscle resection have equivalent success rates.

Surgical treatment for residual or recurrent strabismus

Although the surgical treatment is a relatively effective and predictable method for correcting residual or recurrent strabismus, such as posterior fixation sutures, medial rectus marginal myotomy, unilateral or bilateral rectus re-recession and resection, unilateral lateral rectus recession and adjustable suture, no standard protocol is established for the surgical style. Different surgical approaches have been recommended for correcting residual or recurrent strabismus. The choice of the surgical procedure depends on the former operation pattern and the surgical dosages applied on the patients, residual or recurrent angle of deviation and the operator's preference and experience. This review attempts to outline recent publications and current opinion in the management of residual or recurrent esotropia and exotropia.

Intermittent exotropia: facts, opinions, and unknowns

INTRODUCTION

Intermittent exotropia (IXT) can be a controversial topic, often eliciting lively discussion. This lecture will discuss its definition, incidence, age of onset, presentation, natural variation, criteria for deterioration, goals of treatment, effectiveness of surgical treatment, types of surgical treatment, and unwanted effects of surgical treatment.

METHOD

Results from the scientific literature, opinions of respected colleagues, the opinion of the author, and the results of live polling of the audience during the John Pratt-Johnson lecture are presented.

RESULTS

IXT is defined as an exotropia that is present intermittently predominantly for distance. Its incidence is about 1% and it usually has an onset before age 5. Patients often present because of concern regarding the appearance of the eye misalignment. There is natural variation in the control of IXT, the angle of IXT, and the amount of stereopsis. Criteria that denote deterioration are increasing frequency of IXT, progressively and consistently increasing angle of IXT, loss of binocular vision, and increasing concern regarding the patient's appearance and its effect on social interaction. Goals of treatment are to retain equal or nearly equal vision, to obtain acceptable cosmesis, and to retain binocular vision. The long-term success of surgical treatment is not well proven. Persistent postoperative overcorrection is an unwanted effect of surgical treatment.

CONCLUSION

The inherent biologic variation that occurs when measuring the components of IXT makes it difficult to be dogmatic about IXT, particularly when trying to decide when deterioration is occurring.

One muscle strabismus surgery

PURPOSE OF REVIEW

To describe recent evidence from the literature regarding one muscle strabismus surgery for small- to moderate-angle horizontal deviations.

RECENT FINDINGS

The use of one muscle surgery for comitant strabismus had been controversial because of concerns that it may result in a significant number of undercorrections and/or produce ocular incomitance. Recent evidence in unilateral lateral rectus recession for exotropia, unilateral medial rectus recession for esotropia, and unilateral rectus resections for undercorrected or recurrent strabismus and convergence or divergence insufficiency suggests that unilateral rectus muscle surgery is a safe, effective and predictable procedure for small- to moderate-angle horizontal deviations. Future prospective, comparative studies with larger samples in unilateral rectus muscle surgery are still needed.

SUMMARY

Unilateral rectus muscle surgery is a safe, effective and predictable treatment for small- to moderate-angle horizontal deviations. This procedure limits surgery to one eye, leaves other muscles untouched for repeat surgery, and therefore, should be considered as a primary or alternative approach in the treatment of small- to moderate-angle strabismus.