Bilateral lateral rectus recession for exotropia: a survival analysis

Analysis of postoperative exodrift according to surgical methods for intermittent exotropia

PURPOSE

This study aimed to compare the periods for exodrift stabilization and the long-term surgical outcomes among different surgical methods in intermittent exotropia.

METHODS

The medical records of 350 patients who had undergone intermittent exotropia correcting surgery [unilateral lateral rectus recession-medial rectus resection (R&R, n = 221), bilateral lateral rectus recession (BLR, n = 51) and unilateral lateral rectus recession (ULR, n = 78)] with a postoperative follow-up period of 1.5 years or more were retrospectively reviewed. The deviation angles every 6 months after surgery, periods of exodrift stabilization and surgical outcomes were analysed. The period of postoperative exodrift stabilization was defined as when exodrift was no longer significantly different from that at the next visit (p > 0.05). An alignment of 5 PD (prism diopters) esotropia to 10 PD exotropia at a distance and near fixation was considered surgical success.

RESULTS

The mean angle of exodeviation was significantly different among surgical procedures at postoperative 1 month (BLR > ULR > R&R, p < 0.001); however, there were no differences among the procedures at 6 months (p = 0.088). The periods of exodrift stabilization were 6 months after ULR, 1 year after BLR and 4.5 years after R&R. The surgical success and reoperation rates did not show significant differences among procedures at the final follow-up.

CONCLUSION

Patients undergoing R&R showed smaller exodeviation shortly after surgery but required a longer period to stabilize the exodrift. Following ULR, exodeviation was larger in the early postoperative period, but the exodrift was stabilized earlier. Therefore, the long-term surgical outcomes were similar among ULR, BLR and R&R.

Early post-operative angle as a predictor of surgical success in adult patients with intermittent exotropia

Purpose: Intermittent exotropia is a condition where divergent strabismus is present at certain times or fixation distances and is surgically treated with bilateral lateral rectus recession or unilateral lateral rectus recession with medial rectus resection. The main purpose of our study is to assess the relationship between the initial post-operative deviation and surgical outcomes in adult exotropes undergoing recess-resect surgery. Methods: A retrospective chart review was performed on adult patients who underwent unilateral recess-resect surgery for intermittent exotropia between March 2010 and February 2022 at a single institution with at least 3 months of follow-up. Based on their motor alignment at 2 weeks following surgery, they were categorized as having exodeviation, esodeviation within 10 PD and esodeviation exceeding 10 PD. Surgical success was defined as motor alignment within 10 PD of exotropia and 5 PD of esotropia at distance and near at final follow-up. Results: 93 patients were included, 55% female and average age was 37 years. At postoperative week 2, 26 patients demonstrated residual exodeviation (Group A), 53 patients demonstrated an esodeviation of within 10 PD (Group B) and 14 patients demonstrated an esodeviation greater than 10 PD (Group C). There were no significant differences in pre-operative and demographic factors between the group. At the final follow-up, surgical success was observed in 57 patients: 12 in Group A, 41 in Group B and 4 in Group C (P < .01). Conclusion: Overcorrection of within 10 PD at 2 weeks following surgery showed a more favorable surgical outcome compared to exodeviation or esodeviation exceeding 10 PD.

Long-term surgical outcomes of basic-type exotropia in patients with hyperopia

BACKGROUND

To investigate the surgical outcomes of basic-type exotropia in patients with hyperopia.

METHODS

The medical records of patients who underwent surgery for basic-type exotropia and had been followed up for ≥ 2 years were retrospectively recruited. Patients with myopia and spherical equivalent (SE) < -1.0 diopters (D) were excluded. The patients were classified according to the SE: group H had a SE ≥  + 1.0 D, and group E had -1.0 ≤ SE <  + 1.0 D. The surgical success rate and sensory outcome were compared. Surgical success was defined as exodeviation ≤ 10 prism diopters (PD) and esodeviation ≤ 5 PD at 6 m fixation. Stereoacuity was measured using the Titmus Preschool Stereoacuity Test.

RESULTS

Seventy-five patients (24 males and 51 females, mean age 5.1 ± 2.6 years, range 2.7-14.8) were included. The SE ranged from -0.9 to 4.4 and 21 patients were classified into group H and 54 into group E. The success rates were higher in group H than in group E during the entire follow-up period, but the differences were significant only at the final examination. At the final follow-up, 11 of the 21 (52.4%) patients in group H and 15 of the 54 (27.7%) in group E maintained successful alignment, whereas 10 (47.6%) and 38 (70.4%) patients exhibited recurrence. Overcorrection was exhibited in one (1.9%) patient in group E. Sensory results were comparable between the groups. The follow-up period did not differ between the two groups. The survival analysis showed no difference in the surgical results between the two groups.

CONCLUSIONS

Surgery for basic-type intermittent exotropia resulted in superior outcomes in patients with hyperopia compared to those with emmetropia.

Preoperative and postoperative clinical factors in predicting the early recurrence risk of intermittent exotropia after surgery

PURPOSE

Preoperative and postoperative identification of early recurrence risk factors in intermittent exotropia (IXT) patients after surgery.

DESIGN

Prospective clinical cohort study.

METHODS

We included 210 basic-type IXT patients who underwent either the bilateral rectus recession or unilateral recession and resection procedure and had complete follow-up until recurrence or for more than 24 months postoperatively. The primary outcome was early recurrence, defined as postoperative exodeviation over 11 prism diopters at any time beyond postoperative 1 month and within 24 months. Survival was estimated by the Kaplan-Meier method. Preoperative and postoperative clinical characteristics were collected from patients, and preoperative and postoperative Cox proportional hazards regression analyses were performed. Preoperative model was fit with nine preoperative clinical factors (sex, onset age of exotropia, duration of disease, spherical equivalent of the more myopic eye, preoperative distant exodeviation, near stereoacuity, distant stereoacuity, near control and distant control). Postoperative model was fit by adding two factors relevant to surgery (surgery type and immediate postoperative deviation). Corresponding nomograms were constructed and evaluated using the concordance indexes (C-indexes) and calibration curves. Decision curve analysis (DCA) was used to determine the clinical utility.

RESULTS

The recurrence rate was 8.10% for 6 months, 11.90% for 12 months, 17.14% for 18 months, and 27.14% for 24 months after surgery. Younger onset age, larger preoperative angle and less immediate postoperative overcorrection were found to increase the risk for recurrence. Though onset age and age at surgery were strongly correlated in this study, age at surgery was not significantly associated with IXT recurrence. The C-indexes for the preoperative and postoperative nomograms were 0.66 (95% confidence interval [CI]: 0.60-0.73) and 0.74 (95% CI: 0.68, 0.79), respectively. Calibration plots between predicted and actual observed 6-, 12-, 18-, and 24-month overall survival using the two nomograms revealed high consistency. The DCA indicated that both models yielded great clinical benefits.

CONCLUSIONS

By relatively accurate weighing of each risk factor, the nomograms offer good prediction for early recurrence in IXT patients and may help clinicians and individualized patients make appropriate intervention plans.

Long term surgical outcomes of unilateral recession-resection versus bilateral lateral rectus recession in basic-type intermittent exotropia in children

The long-term results of surgical treatment of intermittent exotropia (X(T)) according to the type of surgery are controversial. We conducted a retrospective cohort study to compare the long-term results between unilateral recession-resection (RR) and bilateral lateral rectus recession (BLR) with an average follow-up of 9.5 years in children with basic-type X(T). Patients with basic-type X(T), who underwent RR (RR group) or BLR (BLR group) and were followed-up for more than 5 years postoperatively, were analyzed. Of the 560 patients, 363 patients received BLR and 197 patients underwent RR. There was no significant difference in the success rates between the two groups until postoperative 3 years. At an average of 9.5 ± 2.6 years after surgery, the success rate of the RR group was significantly higher than that of the BLR group starting from the fourth post-operative year until the last follow-up examination (64.5% vs 43.3%, P < 0.001). By multivariate analysis, preoperative hyperopia of more than + 2.00 diopters, younger age of onset, younger age at surgery, larger exodeviation at near than at distance of > 5 prism diopters, and the type of surgery (BLR) were risk factors of recurrence. In conclusion, RR was more successful than BLR with a lower recurrence rate in the long-term follow-up of patients with basic-type X(T).

Interventions for intermittent exotropia

BACKGROUND

The clinical management of intermittent exotropia (X(T)) has been discussed extensively in the literature, yet there remains a lack of clarity regarding indications for intervention, the most effective form of treatment, and whether there is an optimal time in the evolution of the disease at which any given treatment should be carried out.

OBJECTIVES

The objective of this review was to analyze the effects of various surgical and non-surgical treatments in randomized controlled trials (RCTs) of participants with intermittent exotropia, and to report intervention criteria and determine whether the treatment effect varies by age and subtype of X(T).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2021, Issue 1), which contains the Cochrane Eyes and Vision Trials Register; Ovid MEDLINE; Ovid Embase; Latin American and Caribbean Health Science Information database (LILACS); the ISRCTN registry; ClinicalTrials.gov, and the WHO ICTRP. The date of the search was 20 January 2021. We performed manual searches of the British Orthoptic Journal up to 2002, and the proceedings of the European Strabismological Association (ESA), International Strabismological Association (ISA), and American Association for Pediatric Ophthalmology and Strabismus meeting (AAPOS) up to 2001.

SELECTION CRITERIA

We included RCTs of any surgical or non-surgical treatment for intermittent exotropia.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology.

MAIN RESULTS

We included six RCTs, four of which took place in the United States, and the remaining two in Asia (Turkey, India). A total of 890 participants with basic or distance X(T) were included, most of whom were children aged 12 months to 10 years. Three of these six studies were from the 2013 version of this review. Overall, the included studies had a high risk of performance bias as masking of participants and personnel administering treatment was not possible. Two RCTs compared bilateral lateral rectus recession versus unilateral lateral rectus recession with medial rectus resection, but only one RCT (n = 197) reported on the primary outcomes of this review. Bilateral lateral rectus recession likely results in little difference in motor alignment at near (MD 1.00, 95% CI -2.69 to 4.69) and distance (MD 2.00, 95% CI -1.22 to 5.22) fixation as measured in pupillary distance using PACT (moderate-certainty evidence). Bilateral lateral rectus recession may result in little to no difference in stereoacuity at near fixation (risk ratio (RR) 0.77, 95% CI 0.35 to 1.71), adverse events (RR 7.36, 95% CI 0.39 to 140.65), or quality of life measures (low-certainty evidence). We conducted a meta-analysis of two RCTs comparing patching (n = 249) with active observation (n = 252), but were unable to conduct further meta-analyses due to the clinical and methodological heterogeneity in the remaining trials. We found evidence that patching was clinically more effective than active observation in improving motor alignment at near (mean difference (MD) -2.23, 95% confidence interval (CI) -4.02 to -0.44) and distance (MD -2.00, 95% CI -3.40 to -0.61) fixation as measured by prism and alternate cover test (PACT) at six months (high-certainty evidence). The evidence suggests that patching results in little to no difference in stereoacuity at near fixation (MD 0.00, 95% CI -0.07 to 0.07) (low-certainty evidence). Stereoacuity at distance, motor fusion test, and quality of life measures were not reported. Adverse events were also not reported, but study authors explained that they were not anticipated due to the non-surgical nature of patching. One RCT (n = 38) compared prism adaptation test with eye muscle surgery versus eye muscle surgery alone. No review outcomes were reported. One RCT (n = 60) compared lateral rectus recession and medial rectus plication versus lateral rectus recession and medial rectus resection. Lateral rectus recession and medial rectus plication may not improve motor alignment at distance (MD 0.66, 95% CI -1.06 to 2.38) (low-certainty evidence). The evidence for the effect of lateral rectus recession and medial rectus plication on motor fusion test performance is very uncertain (RR 0.92, 95% CI 0.48 to 1.74) (very low-certainty evidence).

AUTHORS' CONCLUSIONS

Patching confers a clinical benefit in children aged 12 months to 10 years of age with basic- or distance-type X(T) compared with active observation. There is insufficient evidence to determine whether interventions such as bilateral lateral rectus recession versus unilateral lateral rectus recession with medial rectus resection; lateral rectus recession and medial rectus plication versus lateral rectus recession and medial rectus resection; and prism adaptation test prior to eye muscle surgery versus eye muscle surgery alone may confer any benefit.

Quantitative Analysis of Eyeball Rotation During Lateral Gaze in Intermittent Exotropia: A Magnetic Resonance Imaging Study

Purpose

To evaluate the eyeball rotation during lateral gaze in patients with intermittent exotropia (IXT) using three-dimensional magnetic resonance imaging (MRI).

Methods

In this prospective observational study, patients with IXT (n = 29) underwent orbital MRI during central, right, and left gazes. Fixation targets were placed at a 40° angle for lateral gaze. After acquisition of MR images, the position of the static tissues other than the eyeball in the MR images were matched three-dimensionally. The optical axis was defined as the perpendicular line to its lens passing through the corneal vertex. The rotation angle was measured as the angle between optical axes in central gaze and lateral gaze using ImageJ. A difference of 3° or more in the rotational angle between both eyes was considered a significant difference.

Results

Eight patients (26.7%) had a larger adduction angle than the abduction angle of the fellow eye and six patients (20.0%) showed a smaller adduction angle during lateral gaze on at least one side. There was no significant factor associated with the pattern of rotation.

Conclusions

Almost one-half of the patients with IXT had significant difference in the rotation angle between both eyes during lateral gaze. Measurement of the rotation angle during lateral gaze using MRI showed that IXT is not a perfectly comitant disturbance of gaze in some subjects.

Translational Relevance

Quantitative analysis for eye movements using MRI can provide useful information for physiologic mechanism and proper surgical planning in patients with IXT.

Clinical factors affecting the rate of exodrift after surgery in patients with basic intermittent exotropia

We investigated the period of postoperative exodrift during follow-up and clinical factors that affect the rate of exodrift after surgery in the patients with intermittent exotropia (IXT). A retrospective review of medical records of patients with exodrift who underwent bilateral rectus recession for IXT was performed. Exodrift was defined as angle of deviation greater than 10 prism diopters (PD) at distance and near. The median survival period of postoperative exodrift was analyzed using Kaplan Meier survival analysis. The patients were divided into two groups according to the median period of postoperative exodrift (early and late group). The weighted Cox’s proportional hazards regression analysis to investigate the risk factors that affect rate of postoperative exodrift was performed. A total of 108 patients was included. The preoperative angle of deviation at distance and near were 30.3 ± 7.2 PD and 29.5 ± 8.6 PD, respectively. The median survival period of postoperative exodrift was 24 months (range, 6–48 months).The angle of deviation at postoperative day 1 in early and late group were − 3.8 ± 5.5 PD (range, − 16–8 PD) and − 7.7 ± 4.6 PD (range, − 16–4 PD) (p < 0.01). Minus value means esodeviation. In regression analysis, the angle of deviation at postoperative day 1 was the significantly related with rate of exodrift (p < 0.01). The median period of exodrift after surgery was 24 months, angle of deviation at postoperative day 1 could affect the rate of exodrift in patients with IXT.

Surgical outcomes of augmented bilateral lateral rectus recession with conjunctival recession in patients of intermittent exotropia

PURPOSE

To evaluate the surgical outcome of augmented BLR recession with conjunctival recession in cases of IXT.

METHOD

A total of 15 patients of the basic type of IXT were included in this prospective study. The patients underwent augmented BLR recession with conjunctival recession and on the basis of postoperative deviation, the outcome was assessed in terms OF orthophoria/success (< or =10 PD exotropia and < or =5 PD esotropia), residual exotropia/undercorrection (>10 PD exotropia), and overcorrection (>5 PD esotropia).

RESULTS

Preoperative primary horizontal deviation was 30.80 ± 9.56 PD (16-42 PD) for near (0.3 m) and was 33.93 ± 9.97PD (15-45 PD) for distance (6 m). The mean postoperative primary horizontal deviation was 5.6 ± 1.5 PD (4-8 PD) for distance and 6.73 ± 2.15 PD (4-10 PD) for near at 6 months follow-up. After 12 weeks of surgery, 12 (80%) of the patients were orthophoric, 2 (13.3%) of the patients were overcorrected and 1 (6.7%) of the patient was undercorrected for near and all 15 (100.0%) patients were orthophoric for distance. This alignment was maintained till 6 months of follow-up.

CONCLUSIONS

Although fornix-based incisions for squint surgery are preferred these days augmented BLR recession with conjunctival recession by limbal-based incision leads to good surgical outcome and prevents undercorrection and recurrence.

Factors Associated with the Prognosis after Operation in Children with Recurrent Intermittent Exotropia

BACKGROUND

To describe factors affecting the prognosis after operation for recurrent intermittent exotropia (X[T]) in children.

METHODS

Clinical records of 50 patients who underwent operation for recurrent X(T) by a single surgeon were reviewed. The age at diagnosis of X(T), and first and second operations, deviation angle at distance and near, surgical method, concurrent vertical strabismus, stereoacuity, and Worth's Four Dot (W4D) examination before reoperation were analyzed, along with the postoperative deviation angle. A successful surgical outcome was defined as orthophoria, esodeviation ≤ 5 prism diopters, or exodeviation ≤ 10 prism diopters at distance.

RESULTS

Among the 50 recurrent exotropes who underwent surgery and were followed up for more than 1 year postoperatively, 13 showed recurrent exotropia and 1 showed consecutive esotropia. The mean age at reoperation was 8.49 ± 2.19 years, and the mean duration of postoperative follow-up was 27.78 ± 12.02 months. Good near fusion before reoperation was a significant factor in the success of surgery (P = 0.006). Smaller postoperative deviation angle measured immediately and 2 months after surgery were related to smaller final deviation angle (P = 0.027 and P = 0.022, respectively).

CONCLUSION

Peripheral suppression lowers the success rate of operation for recurrent X(T) in children. Overcorrection rather than orthotropia should be the target of immediate postoperative deviation angle. Peripheral suppression status and immediate and 2-month postoperative deviation angle may be important clues for predicting the final result of operation for recurrent X(T).

[Intermittent exotropia]

Intermittent exotropia (IXT) is the most common type of divergent strabismus. It is the consequence of passive mechanisms due to the anatomy of the globes and orbits or due to active innervational mechanisms, resulting in divergence of the visual axes, which is compensated by fusional convergence. Intermittent insufficiency in this compensation gives this form of exotropia its intermittent nature. The most common symptoms of IXT are closure of one eye, asthenopia and diplopia, but they are often absent. The clinical classification of IXT (according to Burian) is based on the difference between the distant and the near angles of deviation. It defines 4 types: true divergence excess (at distance), pseudo-divergence excess, the basic form (distance and near angles are equal) and convergence insufficiency (near angle greater than distance angle). One of the main difficulties in examination of IXT is neutralizing the fusional convergence in order to classify the strabismus. For this purpose, the monocular occlusion test, a near addition, or a prism adaptation test can be used. IXT is also characterised by the quality of control of the deviation by the patient, which is taken in account for therapeutic decision. Tools for measurement of this control have recently been developed and are not commonly used. The natural history of IXT is not well understood. Treatment relies mainly on optical correction, binocular visual training therapy and surgery, but their indications are not well defined, nor are outcomes analysis criteria. In the case of surgery, it aims to treat the maximum measured distance angle; the medium- and long-term angular results of surgery are often disappointing, although it probably improves control of the strabismus in most cases.

Surgical and sensory outcomes in patients with intermittent exotropia according to preoperative refractive error

BACKGROUND/OBJECTIVES

To analyze the surgical and sensory outcomes of intermittent exotropia according to refractive errors and the factors associated with surgical success.

SUBJECTS/METHODS

A total of 326 children were divided into three groups according to preoperative refractive error; hyperopic eyes with SE ≥+2D (hyperopic group), eyes with SE between -1D and +2D (emmetropic group), and myopic eyes with SE ≤-1D (myopic group). The surgical outcomes and the sensory outcomes measured by near and distant stereoacuity were compared among the three groups.

RESULTS

The surgical success rate in hyperopic group was significantly lower compared to myopic group at last follow-up (P = 0.012). Preoperative near stereopsis was not different among three groups, however, the distance stereopsis was significantly deteriorated in the hyperopic group compared to the other two groups (Titmus; P = 0.168, FD2; P < 0.001, DR; P = 0.048). There was postoperative improvement in both near and distant stereopsis in all three groups (Titmus; P = 0.009, FD2; P = 0.021, DR; P = 0.036) and no significant difference was found in the postoperative distant stereopsis among the three groups.

CONCLUSIONS

Preoperative refractive error is a prognostic factor of surgical success in patients with intermittent exotropia. Patients with hyperopia achieved less favorable surgical outcome compared to myopic patients. The preoperative distant stereoacuity was decreased in hyperopic patients compared to myopic patients, which eventually improved after surgery and showed no significant difference at postoperative measurements.

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.

The difference of surgical outcomes between manifest exotropia and esotropia

PURPOSE

To determine the factors that affect ocular alignment and binocular sensory functions after strabismus surgery and compare surgical outcomes between manifest exotropia (XT) and esotropia (ET).

METHODS

In a retrospective study, 41 XT and 17 ET patients who had undergone strabismus surgery were recruited. Information on type and duration of strabismus, age at onset of deviation and surgery, pre- and postoperative strabismus deviation angles, and binocular sensory functions including stereoacuity and macular fusion capacity was recorded.

RESULTS

In all patients, the ocular alignment and binocular sensory functions improved with time following surgery. Residue strabismus deviation angles (≦ 10 prism diopters) at postoperative 1 month determined the final successful ocular alignment. In patients with final excellent binocular sensory functions, XT group restored macular fusion capacity and stereoacuity at postoperative 1 month, but ET group regained macular fusion capacity at postoperative 1 month and then restored stereoacuity at postoperative 3 months. Though XT patients showed better pre- and postoperative stereoacuity than ET patients, patients with successful ocular alignment had an odd of 4.5 in XT group and 22.5 in ET group to achieve excellent and fair binocular sensory functions.

CONCLUSION

Surgical correction of strabismus could improve ocular alignment and binocular sensory functions in patients with manifest strabismus, regardless of onset age, strabismus duration, or type. Postoperative 1-month status may help to predict the final motor and sensory outcomes. ET patients would benefit more final successful ocular alignment and excellent binocular sensory functions from early surgery and maintaining postoperative small deviation angle than XT patients.

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.].

Comparison of Long-term Surgical Outcomes of Two-muscle Surgery in Basic-type Intermittent Exotropia: Bilateral versus Unilateral

Purpose

To compare long-term surgical outcomes after bilateral lateral rectus recession (BLR) and unilateral lateral rectus recession-medial rectus resection (RR) for the treatment of basic-type intermittent exotropia.

Methods

Consecutive patients who underwent BLR or RR for treatment of intermittent exotropia between 1999 and 2010 and underwent ≥5 years of follow-up were recruited for this study. Surgical outcomes were grouped according to postoperative angle of deviation: overcorrection (esophoria/tropia >8 prism diopters [Δ]), success (esophoria/tropia ≤8Δ to exophoria/tropia ≤8Δ), and undercorrection/recurrence (exophoria/tropia >8Δ). Outcomes were compared between the BLR group and the RR group at postoperative week 1, months 1 and 6, and years 1, 2, 3, 4, and 5.

Results

Of 99 patients, 37 underwent BLR and 62 underwent RR. At postoperative month 6 (97.3% vs. 82.3%, p = 0.045) and year 1 (91.9% vs. 74.2%, p = 0.040), the surgical success rates in the BLR group were significantly higher than in the RR group. Recurrence of exophoria/tropia most commonly occurred between 2 and 3 years after surgery in the BLR group, but continuous recurrences were found in the RR group. At postoperative year 5, the surgical success rate was 54.1% in the BLR group and 41.9% in the RR group (p = 0.403). The reoperation rate was 24.3% in the BLR group and 33.9% in the RR group (p = 0.317).

Conclusions

Surgical outcomes 5 years after surgery for intermittent exotropia were comparable between the BLR and RR groups. The surgical success rate and the reoperation rate were not significantly different between the BLR and RR groups.

Long-term outcome following bilateral lateral rectus recession for intermittent exotropia

Background: Bilateral lateral rectus recession is the most common surgical treatment of intermittent exotropia in children. Success rates in previous studies differ because longer follow-up periods may change success rate as the eyes drift out with time. Initial overcorrection was thought to be appropriate management, but the preferred initial postoperative deviation has not been well quantified.

Objective: To study long-term outcomes (≥3 years) of bilateral lateral rectus recession for intermittent exotropia and to evaluate factors influencing long-term success.

Methods: This retrospective descriptive study reviews patients with intermittent exotropia who underwent bilateral lateral rectus recession with a minimum follow up of 3 years. Long-term motor outcome was classified as good (within 8 prism diopters (PD) of esodeviation and 10 PD of exodeviation), acceptable (exodeviation 11-20 PD), and poor (esotropia >8 PD or exotropia >20 PD). Stereoacuity testing pre- and postoperatively was used to evaluate sensory outcome. Correlation between long-term outcome and various pre- and postoperative factors were analyzed.

Results: A total of 59 patients met the selective inclusion criteria. The mean age at time of surgery was 7.1 years with a mean follow-up time of 4.5 years. At the time of the last visit, 69% (41 patients) had good outcomes, 24% (14 patients) had acceptable outcomes, and 7% (4 patients) had poor outcomes. Initial postoperative ocular deviation significantly correlated with long-term outcome (P < 0.05). Mean initial postoperative ocular deviation of patients with good outcome was esodeviation 12.7 PD (range ortho to esodeviation 25 PD). In 45 patients whose stereoacuity could be assessed, 58% (26 patients) had stereoacuity improvement.

Conclusion: Good long-term motor outcome can be achieved in 69% of patients following bilateral lateral rectus recession for intermittent exotropia. Initial postoperative ocular deviation correlated with long-term motor success.

Type of the recurrent exotropia after bilateral rectus recession for intermittent exotropia

Background

The aim of this study was to investigate the type of exotropia (XT) based on the distance-near (D/N) difference in recurrent XT after bilateral lateral rectus (BLR) recession to treat intermittent XT (IXT) to look into the possibility of secondary convergence insufficiency (CI)-type strabismus.

Methods

A total of 121 patients with recurrent XT after BLR recession for basic-type and divergence excess (DE)-type IXT were retrospectively enrolled at a single institution. The distributions in the XT types were compared according to the D/N difference between primary and recurrent XT.

Results

Preoperatively, the population comprised 14 divergence excess (DE) types and 107 basic types. After the BLR recession, the XT-type composition changed to 59 basic types, 33 CI types, and 29 DE types. In one of the 14 preoperatively identified DE-type XT cases, the XT type changed to CI type, it changed to basic type in four cases, and the remaining nine cases showed no change in the DE type. The 107 preoperatively identified basic-type XT cases postoperatively became 55 basic-type, 32 CI-type, and 20 DE-type recurrent XT cases, and their postoperative distance XT control grades and near stereoacuity values did not significantly differ.

Conclusion

The XT type composition changed after the BLR recession. The XT types in recurrent XT after BLR recession showed an increasing proportion of CI-type. We suspect that an individual fusion mechanism might also influence the XT-type in recurrent XT in view of the somewhat increased DE-type in recurrent XT.

An external pilot study to test the feasibility of a randomised controlled trial comparing eye muscle surgery against active monitoring for childhood intermittent exotropia [X(T)]

INTRODUCTION

The evidence base for the treatment of strabismus (squint) is poor. Our main aim is to improve this evidence base for the treatment of a common type of childhood squint {intermittent exotropia, [X(T)]}. We conducted an external pilot study in order to inform the design and conduct of a future full randomised controlled trial (RCT).

METHODS

Children of between 6 months and 16 years with a recent diagnosis of X(T) were eligible for recruitment. Participants were recruited from secondary care at the ophthalmology departments at four UK NHS foundation trusts. Participants were randomised to either active monitoring or surgery. This report describes the findings of the Pilot Rehearsal Trial and Qualitative Study, and assesses the success against the objectives proposed.

RECRUITMENT AND RETENTION

The experience gained during the Pilot Rehearsal Trial demonstrates the ability to recruit and retain sites that are willing to randomise children to both trial arms, and for parents to agree to randomisation of their children to such a study. One child declined the group allocation. A total of 231 children were screened (expected 240), of whom 138 (60%) were eligible (expected 228: 95%) and 49 (35% of eligible) children were recruited (expected 144: 63% of eligible). Strategies that improved recruitment over the course of the trial are discussed, together with the reasons why fewer children were eligible for recruitment than initially anticipated. Attrition was low. Outcome data were obtained for 47 of 49 randomised children.

TRIAL PROCESSES AND DATA COLLECTION

The Trial Management processes proved effective. There were high levels of completion on all of the data collection forms. However, the feedback from the treatment orthoptists revealed that some modifications should be made to the length and frequency of the health service assessment and travel assessment questionnaires, thus reducing the burden on participants in the main trial. Modifications to the wording of the questions also need to be made.

MONITORING OF BIAS

Children who recruited to the trial were older and had more severe strabismus than those children eligible but declining participation. Strategies to account for this in a full trial are proposed.

REASONS FOR PARTICIPATION OR DECLINING STUDY

These were identified using qualitative interviews. The principal reasons for declining entry into the study were strong preferences for and against surgical treatment.

HARMS

There were no serious unexpected adverse events. Two children had overcorrection of their X(T) with reduction in binocular vision following surgery, which is in line with previous studies. No children in the active monitoring arm developed a constant strabismus although two showed some reduction in control.

CONCLUSIONS

The SamExo study has demonstrated that it is possible to recruit and retain participants to a randomised trial of surgery compared with active monitoring for X(T). For longer-term full RCTs, in order to maximise the generalisability of future studies, consideration needs to be given to planning more time and clinic appointments to assess eligibility and to allow consideration of participation; the greater use of research nurses for recruitment; and accommodating the strong preferences of some parents both for and against surgical intervention.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN44114892.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 39. See the NIHR Journals Library website for further project information.

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.

Comparison of long-term surgical outcomes of 2-muscle surgery in children with large-angle exotropia: bilateral vs unilateral

PURPOSE

To evaluate the long-term results of 2-muscle surgery in children with primary large-angle exotropia, comparing 10 mm bilateral lateral rectus recession (BLR) with unilateral lateral rectus recession-medial rectus resection (recess/resect).

DESIGN

Retrospective case series.

METHODS

Eighty-six children with exotropia of ≥40 prism diopters (PD), who underwent the 10 mm BLR (BLR group) or the unilateral recess/resect procedure (RR group) based on the largest angle measured at distance or near were included. Patients were followed-up for more than 2 years. Final successful alignment rates, stereopsis, and factors related to recurrence and overcorrection were evaluated.

RESULTS

At the final examination, 29 (60.4%) of 48 patients in the BLR group achieved successful alignment; 16 (33.3%) had recurrence, and 3 (6.3%) had overcorrection. In the RR group, 26 of 38 patients (68.4%) were successfully aligned, 10 (26.3%) had recurrence, and 2 (5.3%) had overcorrection. Successful alignment and recurrence rates were not significantly different in the groups (P = .371 and .640, respectively). The overcorrection rate was significantly higher in the RR group (P = .014) until 2 years after surgery, but this difference was not significant afterward (P = 1.000). In patients with an exodeviation of ≥45 PD, the recess/resect procedure showed higher successful alignment rates at the final examination (P = .006).

CONCLUSIONS

The long-term successful alignment rate of 2-muscle surgery in children with primary large-angle exotropia was 64%, and the overall surgical outcomes were comparable between the BLR and RR groups. However, in patients with exotropia of ≥45 PD, the unilateral recess/resect procedure resulted in more favorable long-term outcomes.

Outcome of unilateral lateral rectus recession and medial rectus resection in primary exotropia

BACKGROUND

The purpose of this study was to measure the success rate of unilateral lateral rectus recession and medial rectus resection in primary exotropia.

METHODS

This is an interventional case series of 55 patients with primary exotropia (degree of deviation 15-85 PD), above the age of 5 years. Patients were treated in the Department of Ophthalmology, Jinnah Postgraduate Medical Center, Karachi, Pakistan, during the period of July 2009 to March 2010. All the patients underwent surgical procedure i.e., lateral rectus muscle recession (maximum up to 10 mm) and medial rectus muscle resection (up to 6 mm) of one eye, according to the Park's method. Surgery was done based on prism cover test measurements obtained at 6 m with appropriate optical correction in place. Patients were re evaluated at one day, one month, two months and six months post operatively. Final outcome was considered at the end of six months at which achievement of ≤10 PD of exotropia was the success. Data was analyzed on SPSS version 17.0.

RESULTS

We obtained success (≤10 PD) in 42 out of 55 patients (76.4%) and 13 out of 55 patients (23.6%) did not meet our criteria for surgical success (>10 PD). Analysis of success with the type of primary exotropia showed that success was achieved in 22 out of 24 cases of intermittent type (91.6%) and 20 out of 31 cases of constant type (64.5%)(P Value 0.019). The highest percentage of success was achieved in patients with the pre-operative deviation of ≤70 PD i.e., 93.3% (42 out of 45 cases), while none of the patients with the pre-operative deviation of >70 PD (10 out of 10 cases) achieved the criteria for success.

CONCLUSION

We conclude that pre-operative deviation is one of the strongest predictor for favorable surgical outcome. Therefore, eliminating the factors causing error in the correct determination of pre-operative deviation should improve the success and predictability of the surgical outcome. Despite the obstacles in the surgical management of strabismus, our results are encouraging.

Interventions for intermittent exotropia

BACKGROUND

The clinical management of intermittent exotropia has been discussed extensively in the literature, yet there remains a lack of clarity regarding indications for intervention, the most effective form of treatment and whether or not there is an optimal time in the evolution of the disease at which any treatment should be carried out.

OBJECTIVES

The objective of this review was to analyse the effects of various surgical and non-surgical treatments in randomised trials of participants with intermittent exotropia, and to report intervention criteria and determine the significance of factors such as age with respect to outcome.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library, Issue 4, 2012), MEDLINE (January 1966 to May 2012), EMBASE (January 1980 to May 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to May 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 4 May 2012. We are no longer searching the UK Clinical Trials Gateway (UKCTG) for this review. We manually searched the British Orthoptic Journal up to 2002, and the proceedings of the European Strabismological Association (ESA), International Strabismological Association (ISA) and American Academy of Paediatric Ophthalmology and Strabismus meeting (AAPOS) up to 2001. We contacted researchers who are active in the field for information about further published or unpublished studies.

SELECTION CRITERIA

We included randomised controlled trials of any surgical or non-surgical treatment for intermittent exotropia.

DATA COLLECTION AND ANALYSIS

Each review author independently assessed study abstracts identified from the electronic and manual searches. Author analysis was then compared and full papers for appropriate studies were obtained.

MAIN RESULTS

We found one randomised trial that was eligible for inclusion. This trial showed that unilateral surgery was more effective than bilateral surgery for correcting the basic type of intermittent exotropia.

AUTHORS' CONCLUSIONS

The available literature consists mainly of retrospective case reviews, which are difficult to reliably interpret and analyse. The one randomised trial included found unilateral surgery more effective than bilateral surgery for basic intermittent exotropia. However, across all identified studies, measures of severity and thus criteria for intervention are poorly validated, and there appear to be no reliable natural history data. There is therefore a pressing need for improved measures of severity, a better understanding of the natural history and carefully planned clinical trials of treatment to improve the evidence base for the management of this condition.

Contralateral lateral rectus recession versus recess-resect for recurrent exotropia after unilateral recess-resect

BACKGROUND

To compare outcomes following contralateral lateral rectus (LR) recession and recess-resect (RR) procedures for recurrent exotropia of 20-25 prism dioptres (PD) after unilateral RR.

METHODS

39 subjects were included in this retrospective study. All underwent, as a primary surgery for intermittent exotropia, unilateral RR on the non-dominant eye. They were assigned to the subsequent contralateral LR recession (LR, n=19) or RR (n=20) group for recurrent exotropia of 20-25 PD. Surgical success was defined as alignment between 5 PD esodeviation and 10 PD exodeviation.

RESULTS

The mean follow-up duration after the reoperation was 32.3±26.4 months in the LR group and 30.5±26.8 in the RR group (p=0.945). The mean deviation angles at postoperative 1 day were -0.7 PD (overcorrection) in the LR group and -4.3 PD in the RR group (p=0.047). The deviation angles at 3 and 6 months postoperatively were not significant (p=0.771, p=0.923). The final successful outcome was achieved in 63.2% of patients in the LR group and in 65% of patients in the RR group (p=0.905).

CONCLUSIONS

Contralateral LR recession was found to be a safe and effective procedure for the treatment of recurrent exotropia of 20-25 PD after unilateral RR for intermittent exotropia. With LR recession, the intentional overcorrection in the immediate postoperative period could be avoided.

Postoperative stabilization of the strabismic angle in intermittent exotropia

Purpose

To analyze the postoperative strabismic angle for five years or more and to investigate when the angle stabilized in intermittent exotropia.

Methods

We retrospectively reviewed the clinical records of 89 patients who had undergone surgery for intermittent exotropia. The postoperative strabismic angles measured were analyzed at one-year intervals up to five years postoperatively. We divided them into two groups according to their age at the time of surgery. Group 1 was less than 5 years of age, while Group 2 participants were 5 years of age or older.

Results

For our 89 total patients, average exo-angles were 7.8 ± 7.26, 7.9 ± 7.51, 9.5 ± 7.05, 10.1 ± 6.87, and 9.4 ± 6.90 prism diopters at one, two, three, four, and five years postoperatively, respectively. Average exo-angles between postoperative year one and year three, as well as between postoperative year two and year three, were statistically significant (p = 0.015, 0.022). However, the angles were not statistically significant between postoperative year three and year four or between years three and five, respectively (p = 0.707, p = 0.948). The stabilization characteristics of the angle were somewhat different according to age group. In Group 1, the average exo-angle in postoperative years one and three were statistically significant (p = 0.016), but the angle in the same period was not statistically significant in Group 2 (p = 0.203).

Conclusions

There was no significant interval change after three years postoperatively in intermittent exotropia, but if the patient's age at surgery was 5 years or higher, no significant change of exo-angle was found following postoperative year one in this study.

Prognostic factors for recurrence after bilateral rectus recession procedure in patients with intermittent exotropia

PURPOSE

The purpose of this study is to evaluate prognostic factors, specifically age, at the time of surgery, for recurrence after bilateral lateral rectus recession (BLR) in patients with intermittent exotropia.

METHODS

Medical records of 511 subjects who underwent BLR procedures between the ages of 3 and 10 years with more than 12 months of follow-up were retrospectively reviewed. Patients' surgical outcomes with a deviation of less than 10 prism diopters (PD) exotropia and less than 5 PD esotropia were defined as a success. Outcomes with more than 11 PD exotropia were designated as recurrences, and those with esotropia of more than 5 PD after 3 months of surgery were noted as overcorrection. Prognostic factors for recurrence were analyzed by multivariate logistic regression test.

RESULTS

Of the 511 subjects, 371 had successful surgical outcomes and 129 had recurrences, whereas 11 were found to be overcorrected. Age at surgery and immediate postoperative alignment proved to be significant factors influencing a favorable outcome by multivariate logistic regression analysis (P<0.05). However, gender, photophobia, age at onset, spherical equivalent (SE) refractive error, astigmatism, SE anisometropia, and preoperative deviation size were not significantly predictive of success (P>0.05).

CONCLUSION

In BLR procedures, increasing patient age at surgery was associated with lower recurrence rates.

The long-term survival analysis of bilateral lateral rectus recession versus unilateral recession-resection for intermittent exotropia

PURPOSE

To conduct a comparison of the long-term surgical outcomes of bilateral lateral rectus recession (BLR) vs unilateral lateral rectus recession-medial rectus resection (RR) in treatment of intermittent exotropia.

DESIGN

Nonrandomized, retrospective case series.

METHODS

Consecutive patients who underwent BLR or RR for treatment of intermittent exotropia between 2002 and 2006 and had ≥2 years' follow-up were recruited. Surgical outcomes were grouped according to postoperative angle of deviation as overcorrection (esophoria/tropia >5 Δ), success (esophoria/tropia ≤5 Δ to exophoria/tropia ≤10 Δ), or undercorrection/recurrence (exophoria/tropia >10 Δ), and were compared between the BLR group and the RR group at postoperative 1 day, 1 month, 6 months, 1 year, and 2 years, and at the final examination.

RESULTS

Of 128 patients, 55 underwent BLR and 73 underwent RR. The mean follow-up period was 44.2 months in the BLR group and 47.8 months in the RR group. At 1 day, 1 month, 6 months, 1 year, and 2 years after surgery, surgical outcomes in each group were not different (P > .05) However, the final outcome at a mean of 3.8 years was significantly different between the groups, demonstrating a higher success rate in the BLR group than in the RR group (58.2% vs 27.4%, P < .01). Cumulative probability of survival from recurrence was higher in the BLR group than in the RR group (P = .01, log-rank test). Recurrences were most common within 6 months from surgery; however, after that, recurrences occurred continuously in the RR group and rarely in the BLR group.

CONCLUSION

Surgical outcomes by 2 years after surgery for intermittent exotropia were not different between the BLR and RR groups. However, final outcomes were better in the BLR group than in the RR group. This may be caused by the difference of recurrence rate over time: continuous recurrence of exotropia occurred in the RR group, while recurrence was low in the BLR group after postoperative 6 months.

Postoperative outcomes of patients initially overcorrected for intermittent exotropia

BACKGROUND

Esotropic overcorrection on postoperative day 1 after surgery for intermittent exotropia is generally thought to increase the likelihood of long-term satisfactory alignment; however, it is unclear why some patients who are initially overcorrected demonstrate recurrent intermittent exotropia whereas others maintain esotropic to orthotropic alignment.

METHODS

The records of all patients who underwent primary surgical correction of intermittent exotropia were reviewed; those with any degree of esotropia on postoperative day 1 were included. The status at the last visit was categorized as orthotropic to <8(Δ) exotropia or having recurrent exotropia >8(Δ), monofixational esotropia <10(Δ), or esotropia >10(Δ).

RESULTS

A total of 63 patients met the inclusion criteria. The mean postoperative day 1 alignment was 6(Δ) ± 3(Δ) esotropia at distance and 5(Δ) ± 3(Δ) esotropia at near. At the last visit, 31 (49%) were orthotropic to <8(Δ) exotropia, 26 (41%) had recurrence of exotropia >8(Δ), and 6 (10%) had monofixational esotropia <10(Δ). There was no significant difference between outcome groups in onset age, age at surgery, stereopsis, deviation (preoperatively or on postoperative day 1), or follow-up length. Risk factor analysis revealed no association between exotropia type, surgical approach, or postoperative day 1 alignment and risk of recurrent intermittent exotropia or monofixational esotropia, although there was a trend toward recurrent intermittent exotropia in those least overcorrected.

CONCLUSIONS

Recommended overcorrection on postoperative day 1 for intermittent exotropia can result in esotropia, intermittent exotropia, or orthotropia. The results of overcorrection for exotropia are variable and unpredictable. We were unable to determine associations with the recurrence of exotropia or secondary esotropia.

Initial postoperative deviation as a predictor of long-term outcome after surgery for intermittent exotropia

PURPOSE

To determine the relationship between initial postoperative deviation and long-term results after surgery for intermittent exotropia.

METHODS

A nonrandomized, retrospective case series. The records of patients who underwent surgery for intermittent exotropia between 2002 and 2006 and had 2 or more years of follow-up were evaluated. Distance alignment at postoperative week 1 was used to predict long-term surgical outcomes. A successful outcome was defined as no recurrence of exodeviation (exotropia/phoria >15(Δ)) at last follow-up.

RESULTS

A total of 81 patients with mean age of 7.2 years at surgery (range, 1.3-16.9) were included. Bilateral lateral rectus recession was performed in 24 patients, unilateral recession and resection in 48, and unilateral lateral rectus recession in 9. At postoperative week 1, 41 patients had orthophoria or undercorrection (0(Δ)-18(Δ) exotropia/phoria; Group A), 28 had esotropia/phoria ≤10(Δ) (Group B), and 12 had esotropia/phoria >10(Δ) (Group C) at distance. At 2 years after surgery, 12 patients (29%) in Group A, 3 patients (11%) in Group B, and none (0%) in Group C had recurrent exotropia. The recurrence rates within 2 years of surgery significantly differed between groups (P = 0.03). The long-term recurrence rates did not significantly differ in the 3 groups after a mean of 51 ± 23 months' follow-up.

CONCLUSIONS

Although initial overcorrection after intermittent exotropia surgery may be associated with lower probability of recurrence within 2 years after surgery, it cannot predict long-term motor outcomes.

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.

Outcome study of unilateral lateral rectus recession for small to moderate angle intermittent exotropia in children

PURPOSE

To report an outcome study of 100 consecutive children with intermittent exotropia treated by unilateral rectus recession for small to moderate angle exodeviation with a minimum follow-up of 6 months.

METHODS

The records of patients with intermittent exotropia younger than 15 years who underwent 7-to-10-mm unilateral lateral rectus recession for exodeviation measuring 15 to 35 prism diopters (PD) from January 2000 to July 2008 were retrospectively reviewed. The surgery were performed accordingly to the amount of distance deviation. A successful alignment was defined as an exodeviation of 5 PD or less and absence of any esotropia in primary and lateral gaze while viewing distant or near targets.

RESULTS

Successful alignment was achieved in 99%, 88%, and 76% of patients at early postoperative, 6-month, and final follow-up, respectively. One overcorrected patient had an esodeviation of 20 PD at 6 months. The results of the final follow-up did not depend on age or refraction at the level of 0.05, whereas the amount of initial exodeviation was found to be significantly correlated with success at the final examination (P = .041). There was a positive significant relationship between results at 6 months and final follow-up (P = .000, r = 0.449). Eleven of the 13 patients who had a second surgery and were observed more than 6 months had successful alignment. Eighty-nine percent of the patients achieved a successful outcome with the combined primary and secondary surgery at the final follow-up.

CONCLUSION

Unilateral lateral rectus recession is a safe and effective treatment for small to moderate angle intermittent exotropia in children.

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

PURPOSE

To compare outcomes after bilateral and unilateral medial rectus (BMR/UMR) resection for the treatment of recurrent exotropia after bilateral lateral rectus (BLR) muscle recession.

DESIGN

Retrospective, cohort study.

METHODS

Forty-four patients underwent BMR resection (BMR group) or UMR resection (UMR group) for recurrent constant exotropia of 25 prism diopters (PD) or less at distance after undergoing BLR muscle recession for intermittent exotropia in an institutional setting. The main outcome measures were final success rates and improvement in stereopsis and were compared between the groups. The risk factors for recurrence after reoperation also were evaluated. Secondary outcome measures were evaluated based on the drift of ocular alignment toward exodeviation after surgery (exodrift) from postoperative day 1.

RESULTS

Thirteen (54%) of 24 patients in the BMR group had successful outcomes, 10 (42%) had overcorrection, and 1 (4%) had undercorrection at the last follow-up examination. Sixteen (80%) of 20 patients in the UMR group had successful outcomes, 2 (10%) had undercorrection, and 2 (10%) had overcorrection. The incidence of successful outcomes at the last follow-up examination and the incidence of recurrence were not significantly different between the 2 groups, whereas the incidence of overcorrection was significantly higher in the BMR group (P = .017).

CONCLUSIONS

Large UMR resection is a safe and effective procedure in the treatment of small to moderate angles of recurrent exotropia after BLR muscle recession. The overcorrection rate was significantly lower after UMR resection than it was after BMR resection.

Timing of Surgery for Primary Exotropia in Children

OBJECTIVE

To compare postoperative alignment and sensory functions in children with primary exotropia who were operated at an early age (< 7 years) with patients who were operated at an older age (> 7 years).

METHODS

In a consecutive retrospective cohort study, 112 patients who had a surgical intervention for primary exotropia between 1997 and 2003 were evaluated for postoperative results. After applying criteria for eligibility, the group of patients was divided into two groups: those who had surgical intervention before the age of seven years (n = 24) and those who had surgery after the age of seven years (n = 36). Age at surgery, preoperative alignment and sensory functions were correlated with the postoperative status. The follow-up was at least one year (1.0 year to 7 years; median: 2.3 and 3.5 years, respectively).

RESULTS

Children who had surgery before the age of seven had significantly better alignment and sensory functions. The univariate logistic regression model confirmed a statistically significant association between motor outcome (exodeviation less than 10 prism-diopters) and age at the time of surgery (before or after the age of seven; p = 0.002). In the multivariate model, the association between age at time of surgery and motor outcome was even stronger. The number of reoperations in the group operated before the age of 7 years was significantly less than in the group operated after the age of seven (2 versus 12, p = 0.023).

CONCLUSION

The postoperative alignment and sensory functions in patients with primary exotropia who had surgical intervention before the age of seven years were, in this study, better than in patients who had surgery after the age of seven years.

Postoperative outcomes in children with intermittent exotropia from a population-based cohort

PURPOSE

To describe the long-term surgical outcomes in a population-based cohort of children with intermittent exotropia.

METHODS

The medical records of all children (<19 years) who were diagnosed with intermittent exotropia as residents of Olmsted County Minnesota, from January 1, 1975, through December 31, 1994, and managed with surgery were retrospectively reviewed.

RESULTS

Of 184 patients with intermittent exotropia, 61 (33%) underwent surgery at a mean age of 7.6 years (range, 3.2 to 23 years). Twelve of the 61 children (19.7%) underwent a second surgery (10 for recurrent exotropia and 2 for consecutive esotropia), and no patient received 3 or more surgeries during a mean follow-up of 10 years from the first surgery. The final postoperative measurements were recorded in 56 of 61 patients (92%) at a mean of 7.4 years (range, 0 to 18 years) after the first surgery: 31 of the 56 (55%) were within 9(Delta) of orthotropia at distance and 25 of 55 (45%) had better than 60 seconds of stereopsis. The Kaplan-Meier rate of developing >/=10(Delta) of misalignment after the first surgery was 54% by 5 years, 76% by 10 years, and 86% by 15 years.

CONCLUSIONS

In this population-based study of surgery in children with intermittent exotropia, although only 1 in 5 received a second surgery, after a mean follow-up of 8 years, approximately half were successfully aligned and 45% had high-grade stereopsis.

Effect of muscle relaxants on short-term results of exotropia surgery: a focus on resection procedures

Purpose

We investigated the effect of muscle relaxants (atracurium) on the outcomes of intermittent exotropia surgery under general anesthesia, with a focus on resection procedures.

Methods

Thirty four patients who underwent recession and resection (R&R) were divided into two groups: atracurium usage (group A, n=18) and no atracurium usage (group B, n=16). Patients were divided into two subgroups according to the amount of resection of the medial rectus (MR): less than 5 mm (group 1, n=13) or 5 mm and greater (group 2, n=21). Deviation angles were compared between groups and subgroups. Surgical outcome was defined as successful if distant deviation angles were equal to or less than 10 prism diopters.

Results

The overall postoperative deviation angles did not show statistically significant differences between groups A and B. However, in patients with larger MR resections (≥ 5 mm), the 1 week postoperative distant deviation was significantly larger in group A (1.8±2.6 PD) than in group B (-1.6±4.6 PD, p=0.048 by t-test). The overall undercorrection rate at 3 months postoperatively for group A was 16.7%, which was higher than that of group B (6.3%), and the difference was even larger in subgroups with larger MR resections (≥ 5 mm): 18.2% in group A and 0% in group B.

Conclusions

Patients who underwent R&R procedures under general anesthesia with a muscle relaxant tended to be less corrected than those without muscle relaxant, especially in the early postoperative period and with a larger MR resection equal to or greater than 5 mm. However, there was no significant difference in the later postoperative period.