Bilateral Lateral Rectus Recession Research Articles

The impact of simultaneous correction of the V pattern on the results of surgical treatment in children with intermittent exotropia.

This study is to investigate the impact of the coexistence of basic intermittent exotropia and vertical incomitance in the form of the V and sub-V pattern on the results of surgical correction of intermittent exotropia. The records of 81 pediatric patients who had surgery for intermittent exotropia and a follow-up of more than 1year were reviewed retrospectively. They were divided into groups: a concomitant group which underwent only horizontal muscle surgery of bilateral lateral rectus recession and a V pattern group which had additional inferior oblique recession, further separated into two subgroups: ≥ 15 prism diopters (classic V pattern group) and ≥ 10 < 15 prism diopters (sub-V pattern group). The surgical outcome, deviation control, stereoacuity, and postoperative drift were assessed after 3months and 1year postoperatively. Patients with sub-V and classic V pattern intermittent exotropia showed significantly better surgical success rate (p = 0.025) and less postoperative drift (p = 0.042) than patients without vertical incomitance. One year after surgery, successful surgical outcome was achieved in 83.72% of the vertically incomitant group: 80.76% for the classic V pattern and 88.24% for the sub-V pattern group, while only in 60.53% of nonpattern patients. Patients operated for intermittent exotropia with a coexistent V pattern have consistently better surgical long-term results than those with only horizontal deviation. Additional inferior oblique recessions in the sub V pattern group provided excellent outcomes with no overcorrections; therefore, surgeons should consider addressing vertical incomitance even when the typical criteria for the V pattern are not met.

Outcomes for Intermittent Exotropia Using Three Common Surgical Approaches.

To compare a single surgeon's surgical outcomes for treating intermittent exotropia using bilateral lateral rectus recession (BLR), unilateral lateral rectus recession and medial rectus resection (RR), and unilateral lateral rectus recession and medial rectus plication (RP). A retrospective review of all surgeries for basic intermittent exotropia between 2015 and 2023 was performed. Only patients with initial correction using BLR, RR, or RP were included. Exclusion criteria included age older than 18 years, vertical deviation, any nonrefractive ocular diagnoses, prior ocular surgery, and inadequate follow-up. There were 460 patients identified; 123 met inclusion criteria with 54 in the BLR group, 41 in the RR group, and 28 in the RP group. The average preoperative distance alignment (and standard error) values for the BLR, RR, and RP groups were 25.07 (7.35), 22.44 (5.95), and 23.84 (6.42) prism diopters (PD), respectively. At 1 year, the postoperative distance alignment values for the BLR, RR, and RP groups were 8.72 (7.89), 7.46 (6.31), and 12.83 (6.82) PD, respectively (P = .03). A subanalysis found a significant difference between the BLR and RP (P = .02) and RR and RP (P = .02) groups. There was no difference between the BLR and RR groups (P = .57). This study of three surgical approaches for intermittent exotropia found RP had a significantly larger angle of exodeviation compared to BLR and RR at 1 year of follow-up. Both BLR and RR were equally effective approaches for treating intermittent exotropia. [J Pediatr Ophthalmol Strabismus. 20XX;XX(X):XX-XX.].

SURGICAL OUTCOME OF THREE MUSCLES SURGERY IN ONE SINGLE PROCEDURE OF LARGE-ANGLE EXOTROPIA: A CASE REPORT

Introduction : The management of large-angle horizontal strabismus poses special difficulties. Literature has outlined large-angle strabismus in a variety of ways. A threshold of 40 to 60 PD has been employed to determine large-angle strabismus.&#x0D; Case Illustration : A 19-year-old male with complaint of right eye that had been crossed outward since he was 12 years old. There was 90 prism diopter exotropia in near, distance, upgaze, and downgaze. The patient underwent bilateral lateral rectus recession of 10 mm and unilateral medial rectus resection of 6.5 mm in the right eye. Post-operative outcome revealed orthophoria without any misalignment of prism diopter examination in 1 day, one week, and two weeks follow-up.&#x0D; Discussion : When the deviation exceeds 50 prism diopter, there is no established consensus regarding the number and quantity of extraocular rectus muscles for surgery. The lack of uniform criteria and suggested surgical dosage is the greatest obstacle in using three muscles surgery. In this case, we used surgical dose according to Kenneth Wright exotropia binocular surgery table. We performed bilateral rectus lateral recession of 10 mm and a right rectus medial resection of 6.5 mm. This surgical dose gives good outcome. Moreover, this option can leave one horizontal rectus muscle unharmed.&#x0D; Conclusion : Determination of the surgical dose is essential in the management of large-angle exotropia. Appropriate surgical dose results in excellent outcomes with low risk of residual deviation.

SUCCESSFUL DIFFERENT TREATMENT IN INTERMITTENT EXOTROPIA: CASE SERIES

Introduction : In intermittent exotropia, management's goals are to diminish deviation by improving fusion control.&#x0D; Case Illustration : Case 1: A 19-year-old woman has complained of squinting and blurred vision since the age of 3 years. The visual acuity of both eyes (OU) was 0.05, with a BCVA of 0.63. Hirschberg's test was exotropia 15o . The exotropia after the cover test (Figure 1A) improved without blinking. The prism cover test was 35 D in near and distance. Patient was diagnosed with exotropia, an intermittent basic type with good control, astigmatism, and myopia compositus OU. Three months after, with refraction correction and occlusion, the Hirschberg test revealed orthotropia (Figure 1B). Case 2: A 7-year-old boy has suffered of squinting and blurred vision from the age of 6 years. The visual acuity of both eyes was 0.63 with a BCVA of 1.0. Hirschberg's test was exotropia 30° (Figure 2A). The prism cover test was 50 D in near and distance. Exotropia intermittent basic type, poor control, and bilateral astigmatism were diagnosed in the patients. The patient had surgery for bilateral lateral rectus recession. Hirschberg test 1 day Postoperatively, orthotropia was present (Figure 2B).&#x0D; Discussion : In exodeviation, control mechanisms relate to therapy compliance and different deviation angles. Intermittent exotropia can be progressive due to loss of fusion control and cause persistent deviation.&#x0D; Conclusion : For patients with exotropia with intermittent good control, non-surgical management can give good results. Surgical management is considered for large angle deviations in patients with poor control.

Factors Associated with Surgical Outcomes after Bilateral Lateral Rectus Recession in Children with Intermittent Exotropia

Backgroud: To analyze the factors associated with surgical outcomes after bilateral rectus recession (BLR) in children with intermittent exotropia (IXT). Methods: A retrospective study was performed on 125 patients who had all received preoperative patch treatment with a ≥1 year follow-up. The surgical outcomes were grouped as success (esodeviation ≤5 PD to exodeviation ≤10 PD) or failure (esodeviation &gt;5 PD or exodeviation &gt;10 PD) according to the angle of deviation at 1 year postoperatively. The patients’ magnitude of exodeviation, near and distant stereoacuity, and 3-mo patch responses were assessed. The factors associated with the surgical outcomes were determined using univariate and multivariate analyses. Results: Of the 125 patients, 102 (81.6%) and 23 (18.4%) were assigned to the success and failure groups, respectively. According to the univariate analysis, the absence of anisometropia, a smaller preoperative near exodeviation, a better near stereopsis, a smaller magnitude of deviation on day 1 postoperatively, and response to patching were significantly associated with surgical success for IXT after 1 year. In the multivariate analysis, distant esotropic deviation on day 1 postoperatively and response to patching were the factors affecting successful surgical outcomes. Conclusions: Esotropic distant deviation on day 1 postoperatively is a prognostic factor for favorable surgical outcomes. Preoperative patching could be a factor influencing surgical success in children with IXT.

Outcomes for maximal bilateral lateral rectus recession in large-angle exotropia

Surgical treatment for large-angle exotropia can be challenging. The aim of this study was to evaluate short-term surgical outcomes of patients with large-angle exotropia (≥50Δ) undergoing maximal bilateral lateral rectus muscle recession of 10 mm. This was a retrospective study of consecutive patients at our institution who underwent maximal bilateral lateral rectus muscle recession for exodeviation ≥50Δ from January 1, 2008, to July 22, 2022. We subdivided the cohort into large-angle exotropia (largest amount of exodeviation at near and/or distance ≥50Δ and <65Δ) and very large-angle exotropia (largest exodeviation ≥65Δ). Patients with a history of prior eye muscle surgery, neurologic deficits, and three- or four-muscle surgery were excluded. A total of 22 patients were included. Mean preoperative exodeviation at distance was 51.9Δ in the large-angle group and 67.5Δ in the very-large-angle group (P = 0.001). Outcomes for the large-angle and very-large angle groups were, respectively, as follows: mean follow-up, 31.1 weeks and 11.8 weeks (P = 0.97); success, 75.0% and 16.7% (P = 0.02); undercorrection rates, 18.7% and 83.3% (P = 0.01); and mean postoperative exodeviation at distance, 3.7Δ ± 6.3Δ and 28.0Δ ± 13.5Δ (P = 0.001). Our study identified good surgical outcomes (75%) with maximal bilateral lateral rectus muscle recession of 10 mm in treating patients with large-angle exotropia between 50Δ and <65Δ. Other surgical techniques such as recession-resection and three- or four-muscle surgery may result in better outcomes when treating patients with exotropia ≥65Δ.

Efficacy of part-time patching in preventing recurrence after bilateral lateral rectus recession in children with intermittent exotropia

BackgroundThis study evaluate the efficacy of part-time patching in preventing recurrence after bilateral lateral rectus recession (BLR) in patients with intermittent exotropia (IXT).MethodsA total of 190 children aged 3–13 years who experienced recurrence after BLR for IXT and received part-time patching were retrospectively reviewed. The patching was prescribed for 2 h per day for more than 6 months. Patients who had a recurrence of 18 PD or more underwent reoperation. Changes in exodeviation and reoperation ratio after part-time patching were analyzed.ResultsA total of 34 patients (17.9%) received reoperation after part-time patching, and the reoperation ratio after 2 years was 20.3% as per the Kaplan–Meier survival analysis. Patients with a recurrence of 7 to 10 PD showed a significantly better effect compared to those with a recurrence of more than 10 PD (p < 0.001), and the reoperation ratio was also lower in the survival analysis (p = 0.004). The factor associated with reoperation in patients with part-time patching was the duration between the operation and the initiation of part-time patching (hazard ratio [HR] = 1.006, p = 0.002).ConclusionsPart-time patching was effective in maintaining the efficacy of surgery and delaying the need of reoperation after BLR. This effect was better in patients with a recurrence of ≤ 10 PD.

Outcomes of inferior oblique myectomy versus recession combined with lateral rectus recession in V-pattern exotropias

PurposeTo compare outcomes of bilateral lateral rectus recession (BLRc) paired with either bilateral inferior oblique myectomy (BIOm) or bilateral inferior oblique recession (BIOc) to correct V-pattern exotropia. MethodsThe medical records of children (≤18 years) who underwent BLRc with BIOm or BIOc (10 mm) for V-pattern intermittent exotropia between December 2020 and May 2022 and who had at least 6 months’ postoperative follow-up were reviewed. Outcomes included horizontal alignment, bilateral inferior oblique action, stereopsis, postoperative exotropia control score, and additional strabismus surgeries. Analysis was stratified by preoperative V pattern into subgroups of 10Δ-14Δ and ≥15Δ. ResultsFifty patients underwent BLRc with BIOm (n = 26) or BIOc (n = 24), with no difference in age, sex, or follow-up length. Preoperatively, there were no differences in stereopsis, horizontal or vertical deviations in primary position, strabismus control, or inferior oblique overaction (IOOA). The BIOc group had greater preoperative V pattern than the BIOm group (18.1 ± 6.8 D vs 14.3 ± 7.0 D, resp. [P = 0.03]). There was no difference in BLRc surgical dose. At final follow-up (mean, 448 ± 189 days), both groups showed a postoperative decrease in horizontal deviation, amount of V pattern, and IOOA. For patients with ≥15Δ V pattern, BIOm decreased V pattern amount at distance (P = 0.02) and IOOA (P = 0.0035) more than BIOc, and BIOm patients had better control of residual strabismus at distance (P = 0.03) compared with the BIOc group overall, as well as for both V pattern subgroups. Two patients with BIOm and one with BIOc underwent additional strabismus surgery. ConclusionsBIOm or BIOc in combination with BLRc decreased the angle of exotropia and improved control. However, BIOm, especially with large V patterns, had a greater effect on decreasing the V pattern and IOOA and showed better control of residual strabismus.

Surgical outcomes of bilateral lateral rectus recession versus unilateral recession and resection for the divergence excess type of intermittent exotropia.

To compare bilateral lateral rectus recession (BLR) with unilateral recession and resection (RR) for divergence excess intermittent exotropia (IXT). Retrospective analysis of 66 patients with divergence excess IXT who underwent either BLR or RR from January 2013 to December 2020 was conducted. Data on demographics, pre- and postoperative deviations, fusion, stereopsis, control, and accommodative convergence/accommodation ratio were collected. Success was defined as esodeviation ≤5 PD (prism diopter) to exodeviation ≤10 PD with a follow-up time of at least 8.0 ± 2.0 weeks. BLR (42 cases) and RR (24 cases) groups had the same success rate (83.3%, P = 0.688) and similar reduced postoperative deviations both in distance and at near (P > 0.05). Near-distance disparity decreased significantly in both groups (P = 0.000) with no intergroup difference (P = 0.193). BLR and RR were equally effective for divergence excess IXT with comparable outcomes of both distance and near deviations.

Surgical management of superior oblique palsy with coexisting exotropia

To analyze the surgical results of patients treated for superior oblique palsy with coexisting exotropia. The medical records of patients with superior oblique palsy and exotropia who underwent inferior oblique weakening and simultaneous lateral rectus recession by a single surgeon from 1996 to 2022 were reviewed retrospectively. Demographics, pre- and postoperative vertical and horizontal deviation, and presence of diplopia were recorded. Surgical success was defined as horizontal deviation <10Δ and vertical deviation ≤4Δ without overcorrection or diplopia. The decision to operate for the horizontal deviation was made based on fusion in free space when the vertical deviation was offset with a prism. A total of 27 patients were included. Mean age was 26.1 ± 22 years (range, 26 months to 78 years). Preoperatively, mean vertical deviation was 15.2Δ ± 7.5Δ (range, 4Δ-30Δ); mean exodeviation, 17Δ ± 5.5Δ (range, 10Δ-35Δ). Of the 27 patients, 25 underwent unilateral and 2 underwent bilateral lateral rectus recession, according to the magnitude of the horizontal deviation. Mean follow-up was 3 ± 3.8 months (range, 2 weeks to 17 months). Postoperative mean vertical alignment was 3.0 ± 5.9, and horizontal alignment was 3.4Δ ± 5.2Δ (esotropia of 7Δ to exotropia of 12Δ; P < 0.0001). Nineteen patients (70%) had a successful result; 2 patients had residual exotropia of >10Δ, 2 had vertical overcorrection (range, 3Δ-4Δ), and 6 had residual vertical deviation ≥4Δ (range, 5Δ-20Δ). None had secondary esotropia >10Δ. Horizontal deviation was corrected successfully with no consecutive esotropia in 25 patients. In our study cohort, patients with superior oblique palsy and exotropia in whom fusion required both horizontal and vertical prism correction had a high likelihood of successful horizontal alignment after lateral rectus weakening in combination with inferior oblique surgery.

Eight-Year Outcomes of Bilateral Lateral Rectus Recessions versus Unilateral Recession-Resection in Childhood Basic-Type Intermittent Exotropia

To report 8-year outcomes from a randomized controlled trial (RCT) comparing bilateral lateral rectus muscle recession (BLRc) with unilateral recession-resection (R&R) for childhood intermittent exotropia (IXT). Eight-year follow-up of RCT cohort. Of 197 randomized participants, 123 agreed to continue follow-up after the 3-year outcome visit (baseline age, 3-< 11 years; basic-type IXT, 15-40 prism diopters [Δ] by prism and alternate cover test [PACT]; baseline stereoacuity, ≤ 400 arcsec; no prior surgery). After the RCT primary outcome at 3 years, annual follow-up from 4 through 8 years with treatment at investigator discretion. Suboptimal surgical outcome by 8 years after randomization, defined as any of the following at any visit: exotropia of 10 Δ or more by simultaneous prism cover test (SPCT) at distance or near, constant esotropia (ET) of 6 Δ or more by SPCT at distance or near, loss of near stereoacuity by 0.6 log arcsec or more from baseline, or reoperation. Secondary outcomes included (1) reoperation by 8 years and (2) complete or near-complete resolution at 8 years, defined as exodeviation of less than 10 Δ by SPCT and PACT at distance and near and 10 Δ or more reduction from baseline by PACT at distance and near, ET of less than 6 Δ at distance and near, no decrease in stereoacuity by 0.6 log arcsec or more from baseline, and no reoperation or nonsurgical treatment for IXT. The Kaplan-Meier cumulative probability of suboptimal surgical outcome through 8 years was 68% (55 events among 101 at risk) for BLRc and 53% (42 events among 96 at risk) for R&R (difference, 15%; 95% confidence interval [CI], -2% to 32%; P= 0.08). Complete or near-complete resolution at 8 years occurred in 15% (7/46) for BLRc and 37% (16/43) for R&R (difference, -22%; 95% CI, -44% to -0.1%; P= 0.049). The cumulative probability of reoperation was 30% for BLRc and 11% for R&R (difference, 19%; 95% CI, 2%-36%; P= 0.049). Despite no significant difference for the primary outcome, the 95% CI did not exclude a moderate benefit of R&R, which together with secondary outcomes suggests that unilateral R&R followed by usual care may yield better long-term outcomes than BLRc followed by usual care for basic-type childhood IXT using these surgical doses. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Analysis of postoperative exodrift according to surgical methods for intermittent exotropia.

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

Survey of Surgical Management in Intermittent Exotropia

Purpose: To obtain an overview of the surgical practices for the management of intermittent exotropia among experienced surgeons.Methods: We conducted a survey of members of the Korean Association for Pediatric Ophthalmology and Strabismus, who had experience of &gt; 15 years in strabismus surgery, via e-mail. Surgical methods for basic-type intermittent exotropia, angle of deviation for determining the surgical dose, reasons for surgical dose adjustment, and the postoperative target angle of deviation were analyzed.Results: Bilateral lateral rectus recession was preferred over unilateral recession and resection for basic-type intermittent exotropia with or without a dominant eye. The preoperative maximum angle of deviation was preferred for determining the surgical dose by 56% of the participants. Two-thirds of the participants preferred to reduce the surgical dose in specific circumstances, lateral incomitancy being the most common reason. In case of true divergence excess-type intermittent exotropia, 47.7% of the participants reduced the surgical dose. The most preferred target angle of deviation at 1 day postoperatively was 11-15 prism diopter esodeviation, as reported by 40% of the participants.Conclusions: Although experienced surgeons had different surgical preferences for intermittent exotropia, a general trend was found. This survey may be a useful reference for beginners in strabismus surgery.

Correlation between bilateral lateral rectus muscle recession and myopic progression in children with intermittent exotropia

Although several studies have reported about the relationship between the surgical correction of intermittent exotropia and myopic progression, it remains unclear, unlike the relationship between esotropia and hyperopia. Thus, this retrospective case control study evaluated the impact of bilateral lateral rectus recession in intermittent exotropia on myopic progression. This study included 388 patients with intermittent exotropia. The refractive errors and degree of exodeviation at each follow up period were analyzed. The rate of myopic progression was −0.46 ± 0.62 diopter (D)/year in patients who underwent surgery and −0.58 ± 0.78 D/year in patients who did not, with no significant difference between them (p = 0.254). Patients who had recurrences of more than 10 prism diopters were compared with patients who did not have. The rate of myopic progression was −0.57 ± 0.72 D/year in the recurrent group and −0.44 ± 0.61 D/year in the non-recurrent group, with no significant difference between them (p = 0.237). Patients with fast myopic progression had more recurrence than patients with slow progression (p = 0.042). Moreover, recurrence had a positive correlation with fast myopic progression (OR = 2.537, p = 0.021). Conclusively, the surgical correction of intermittent exotropia did not influence myopic progression.

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

ABSTRACT 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.

The long-term surgical outcomes of lateral rectus advancement in consecutive esotropia.

To evaluate the long-term surgical efficacy of lateral rectus advancement (LRadv) in patients with consecutive esotropia (CET). The medical records of 30 patients who developed CET after bilateral lateral rectus (BLR) recession for exotropia (XT) between 2012 and 2020 were reviewed. The characteristics of patients during their XT surgery were summarized. Among them, 15 patients who underwent LRadv as CET treatment with at least a 1-year follow-up were included to evaluate the long-term efficacy of this surgical approach. The main outcomes were the pre- and post-operative angle of deviation after LRadv. Surgical success was defined as the postoperative deviation within 10 prism diopters (PD), and reoperation was not needed. All data were expressed as median and interquartile ranges. The median follow-up was 34months after LRadv surgery. The median postoperative deviation ranged from 28 to 1 PD at 1year (P < 0.05) and to 5 PD at the final follow-up (P < 0.05). The deviation at each follow-up time showed no statistically significant difference (P > 0.05). The final surgical success was reduced compared to 1day and 1year postoperatively (60% VS 100% and 66.7%, respectively). Undercorrection and overcorrection both occurred at the final follow-up. Although the immediate surgical outcome of LRadv was satisfactory, the success rate reduced with time, which suggests long-term observation is necessary to detect and timely provide appropriate interventions for overcorrection or undercorrection.

Botulinum toxin augmented bilateral lateral rectus recession versus three muscles surgery in large-angle intermittent exotropia.

To report the surgical outcomes of correcting large angle intermittent exotropia in adult patients by bilateral lateral rectus muscle recession with intraoperative use of botulinum toxin and to compare the results with those of bilateral lateral rectus muscle recession and unilateral medial rectus resection. The medical records of patients who underwent surgical correction of large angle intermittent exotropia [exotropia >50 prism dioptre (PD)] were retrospectively reviewed. Two groups of patients were identified; Group I (21 patients) had bilateral lateral recti recession augmented with intraoperative botulinum toxin A (BTA) injection into the recessed muscles and group II (30 patients) were treated by bilateral lateral recti recession with unilateral medial rectus muscle resection. Preoperative data were extracted for age, gender, refraction, type of exotropia, angle of stereopsis and angle of deviation. The main outcome measures were the postoperative angle of deviation and stereoacuity angle by Titmus test measured at the end of one year of postoperative follow up. By the end of the first postoperative year, 10 patients in group I (47.6%) and 20 patients in group II (66.7%) achieved esotropia/esophoria <5 PD or exotropia/exophoria <10 PD. The difference in surgical success rate was not statistically significant (P=0.1) but there was a statistically significant higher rate of undercorrection in group I (P=0.03). On the other hand, 3 patients in group I (14.3%) and 5 patients in group II (16.7%) had improved stereopsis; this difference in the sensory outcome was not statistically significant (P=0.8). In the BTA augmented surgery group, good stereoacuity and smaller preoperative angle of deviation were associated with significantly higher surgical success rate (P=0.004, 0.01 respectively). BTA augmented bilateral lateral recti recession is associated with higher rate of undercorrection as compared to bilateral lateral recti recession with unilateral medial rectus resection in the correction of large angle intermittent exotropia. The surgical success rate in BTA augmented surgery group is observed to be higher in patients with preoperative smaller angle of deviation and in patients with good stereoacuity.

Comparison of Surgical Outcomes of Two-muscle Surgery in Children with Large-angle Intermittent Exotropia

Purpose: To evaluate the long-term results of 2-muscle surgery in children with large-angle intermittent exotropia (IXT), comparing bilateral lateral rectus recession (BLR) with unilateral lateral rectus recession &amp; medial rectus resection (RR).Methods: Ninety-two children with IXT of 40 prism diopter or more, who underwent BLR or RR were included in this retrospective study. Final successful alignment rates, and cumulative probabilities of surgical success at 3 years postoperatively were analyzed and compared using Kaplan-Meier survival analysis between the two groups.Results: At 3 years after surgery, 37 (67.3%) of 55 patients in the BLR group achieved successful alignment; 18 (32.7%) had undercorrection, and none of them had overcorrection. In the RR group, 34 (92%) of 37 patients were successfully aligned, two (5%) had undercorrection, and one (3%) had an overcorrection at 3 years after surgery. There was a statistically significant difference in postoperative results between the two groups (p = 0.0012). The cumulative probabilities of surgical success at 3 years postoperatively analyzed using the Kaplan-Meier survival curve were 63% in the BLR group and 92% in the RR group. Postoperative mean recurrence time was 45 months in the BLR group and 50 months in the RR group, showing a significant difference between the two groups (p = 0.0006).Conclusions: The unilateral RR procedure demonstrated more favorable long-term postoperative outcomes than BLR procedure in patients with large-angle IXT.

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.

Comparison between Down Transposition and Slanted Surgery for Bilateral Lateral Rectus Recession in Convergence Insufficiency-Type Exotropia

Purpose: We compared bilateral lateral rectus recession with down transposition and slanted bilateral lateral rectus recession as surgical methods for convergence insufficiency-type exotropia.Methods: We included patients who underwent bilateral lateral rectus recession with down transposition or slanted bilateral lateral rectus recession for convergence insufficiency-type exotropia from January 2012 to January 2021 and observed them for more than 1 year. We retrospectively analyzed sex, age, preoperative best-corrected visual acuity, spherical equivalent, axial length, amount of surgery, and deviation angle before surgery and after surgery (immediately, 1 week, 6 months, and 1 year). We also examined surgical success and stereopsis before surgery and after 6 months and 1 year.Results: The down transposition group included 45 patients and the slanted group included 40. The deviation angle of distance, deviation angle of near and the near-distance disparity (NDD) all decreased in the down transposition group and slanted group 1 year after surgery (1.96 ± 8.77 prism diopter [PD] and 4.60 ± 4.99 PD, respectively; 5.53 ± 9.09 PD and 9.03 ± 9.09 PD, respectively; and 3.58 ± 5.26 PD and 4.43 ± 5.32 PD, respectively). Surgical success after 1 year was 55.6% in the down transposition group and 52.5% in the slanted group, and there was no significant difference between the two groups.Conclusions: In convergence insufficiency-type exotropia, both bilateral lateral rectus recession with down transposition and slanted bilateral lateral rectus recession were effective to correct the deviation angle of near, distance, and NDD. Both are suitable primary surgical methods for convergence insufficiency-type exotropia.