Surgical outcomes in convergence insufficiency-type exotropia

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.

Treatment of convergence insufficiency type intermittent exotropia with bupivacaine injection to the medial rectus combined with lateral rectus recession

PURPOSE

To evaluate the outcomes of combined bupivacaine HCL (BPX) injection in the medial rectus (MR) muscle with recession of the lateral rectus muscle in the treatment of convergence insufficiency-type intermittent exotropia (CI-IXT).

METHODS

The medical records of patients who underwent combined injection-recession treatment from January 2019 to January 2020 for CI-IXT were reviewed retrospectively along with a group of age-matched controls with IXT without CI who underwent only unilateral LR recession during the same period. The following data were extracted from the record: age at surgery, average follow-up period, angle of deviation at distance and near and the difference between them before and after surgical procedure, correction of near and distance deviations, and recession dosage. Successful outcome was defined as a distance deviation in primary gaze between ≤10^Δ of exophoria/tropia and ≤5^Δ of esophoria/tropia.

RESULTS

A total of 10 patients and 20 controls were included. Average follow-up was 13.9 ± 3.67 months in the BPX group and 15.9 ± 3.61 months in the control group (P = 0.17). Postoperative distance deviation measured 8.30^Δ ± 5.88^Δ in the BPX group and 14.67^Δ ± 9.83^Δ in the control group (P = 0.80). Distance-near differences were significantly reduced in the CI-IXT group receiving BPX, by a mean of 6.60^Δ, from a preoperative mean of 10.50^Δ ± 3.65^Δ to 3.90^Δ ± 3.26^Δ (P < 0.01).

CONCLUSIONS

BPX injection combined with unilateral lateral rectus recession yields outcomes comparable to bilateral lateral rectus recession for distance deviations, and results in reduction of the distance-near difference in the angle of exotropia.

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.

Comparative Study of Bilateral Versus Unilateral Strabismus Surgery in the Management of Lateral Incomitance in Intermittent Exotropia

PURPOSE

To evaluate and compare bilateral asymmetric lateral rectus recession versus unilateral resection-recession surgery in the management of lateral incomitance in intermittent exotropia.

METHODS

A prospective randomized interventional comparative study was conducted consisting of 80 patients with intermittent exotropia (older than 7 years) having significant lateral incomitance. They were equally divided into two groups by a sealed envelope system. The bilateral group underwent bilateral asymmetric lateral rectus recession and the unilateral group underwent unilateral lateral rectus recession and medial rectus resection based on post-patch deviation. Parameters assessed were change in horizontal deviation, change in lateral incomitance, binocularity, motility limitation, and complications, if any. Surgical outcome was considered successful if the primary deviation was within ±8 prism diopters (PD) and lateral incomitance was less than 5 PD.

RESULTS

The mean lateral incomitance preoperatively and postoperatively was 8.3 ± 1.6 and 2.8 ± 2.4 PD in the bilateral group and 8.9 ± 1.4 and 3.7 ± 2.5 PD in the unilateral group, respectively. There was no statistically significant difference in the postoperative lateral incomitance between the two groups (P = .25), but a statistically significant difference was observed between preoperative and postoperative lateral incomitance in each group (P < .0001).

CONCLUSIONS

Both procedures are equally efficacious in achieving acceptable ocular alignment and improving significant lateral incomitance in patients with intermittent exotropia with deviations between 15 and 35 PD without causing significant motility limitation. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XX-XX.].

Comparison of surgical outcomes of slanted procedure for exotropia with convergence insufficiency according to their response to preoperative monocular occlusion

The aim of this prospective study was to compare surgical outcomes of slanted bilateral lateral rectus (LR) recession for intermittent exotropia (IXT) with convergence insufficiency (CI) according to their response to preoperative monocular occlusion. This prospective study included 55 children who underwent slanted bilateral LR recession for IXT with CI. Patients were divided into two groups according to their response to preoperative monocular occlusion for 2 hours. The True CI group was defined as having near-distance differences of ≥10 PD before and after occlusion; the Masked CI group as having near-distance differences of <10 PD and ≥10 PD prior to and after occlusion. Slanted procedure reduced distance and near exodeviations from 32.1 PD and 43.0 PD to 3.5 PD and 4.4 PD, and collapsed near-distance differences from 10.9 PD to 1.0 PD at 3 years postoperatively. Cumulative probabilities of surgical success were 76%, and the mean recurrence was 50 months at 3 years postoperatively; the True CI and Masked CI groups showed cumulative success rates of 89% and 55%, respectively (p = 0.0052). Patients in the True CI group demonstrated surgical outcomes superior to those demonstrated by patients in the Masked CI group after slanted bilateral LR recession.

Slanted versus Augmented Recession for Horizontal Strabismus

Purpose

To compare the surgical outcomes of slanted versus augmented recession in patients with horizontal strabismus.

Methods

In this randomized clinical trial, a total of 100 esotropic (ET) and exotropic (XT) patients with a high AC/A ratio which was defined as a difference of ≥ 10 prism diopters (pd) between the distance and near deviations were included if the patients had a distance deviation ≥ 15 pd. Patients were randomly assigned into the slanted (n = 26 in ET and n = 24 in XT group) and augmented recession groups (n = 25 in ET and n = 25 in XT group). In the slanted group, recession was performed on the superior and inferior poles of the muscle based on the distance and near deviations, respectively, while in the augmented recession group, the muscles were recessed 1.00 or 1.50 mm more than the standard amount according to the distance and near difference between 10 and 20 pd or > 20 pd, respectively.

Results

The mean age was 9.8 ± 9.6 years and 63% were female. There was a significant postoperative reduction of difference in convergence excess in ET cases compared to patients who underwent the augmented recession procedure (12.65 ± 6.16 vs 8.64 ± 6.1 pd, P = 0.014). Among our XT groups, there was no significant difference in postoperative reduction in the XT angle in the slanted group compared with the augmented group (P > 0.05).

Conclusion

Slanted recession is recommended in convergence excess ET patients. In XT patients, either slanted or augmented recession may be chosen according to the priority and experience of the surgeon.

Long-term outcomes following resection-recession versus plication-recession in children with intermittent exotropia

Background/Aims

To compare the long-term surgical outcomes between unilateral lateral rectus recession-medial rectus resection (RR) and lateral rectus recession-medial rectus plication (RP) in children with intermittent exotropia.

Methods

Children who underwent RR or RP for intermittent exotropia between January 2008 and July 2016, with a minimum follow-up period of 2 years were retrospectively reviewed. Postoperative angle of deviations and clinical factors including sex, age, refractive errors, preoperative angle of deviation, types of exotropia and stereopsis were investigated. Based on the angle of deviation at year 2, surgical outcomes were classified into two groups as follows: success (esodeviation ≤5 prism dioptres (PD) to exodeviation ≤10 PD) and failure (overcorrection (esodeviation >5 PD) and undercorrection or recurrence (exodeviation >10 PD)).

Results

Of the 186 patients, 114 underwent RR and 72 underwent RP. The angle of exodeviation steadily increased over time in both groups after surgery. The durations of exodrift were longer in the RP group than in the RR group. The surgical success at postoperative year 2 was 55.3% in the RR group and 27.8% in the RP group (p<0.001). The amount of overcorrection was associated with successful outcomes in both groups.

Conclusions

In children with intermittent exotropia, RR group presented better surgical outcomes than RP group. The amount of initial overcorrection was important to achieve favourable outcomes in children with intermittent exotropia.

Surgical outcomes of three different surgical techniques for treatment of convergence insufficiency intermittent exotropia

PurposeTo determine the outcomes of three different techniques of strabismus surgery in patients with convergence insufficiency intermittent exotropia (CI-X(T)).Patients and methodsSixty-seven patients with CI-X(T) with near-distance disparity (NDD) ≥10 prism diopter (PD) were included in this 1-year follow-up prospective study and were randomly divided into three groups: slanted bilateral LR recession (S-BLR) group in which 22 patients underwent bilateral slanting recession of the lateral rectus (LR) muscle, the I-RR group with 23 patients who underwent improved unilateral medial rectus (MR) resection and LR recession with the amounts of resection and recession biased to near and distance deviation, respectively, and the A-BLR group with 22 patients who underwent bilateral augmented LR recession based on the near deviation. A successful outcome at distant and near was defined as exodeviation between 10 PD of exophoria/tropia and 5 PD of esophoria/tropia. Cumulative probabilities of success, preoperative and postoperative distant, near deviations, and NDD among groups were analyzed and compared.ResultsThe success rate of distant exodeviation, near exodeviation, and NDD in the three groups after 1 year was statistically insignificant (P=0.054, 0.233, and 0.142, respectively). At the 1 year follow-up, vertical pattern strabismus (V and A patterns) was a feature of the S-BLR group, whereas the rate of postoperative overcorrection and undercorrection was significant in the A-BLR and I-RR groups, respectively.ConclusionThe success rate of correction of distant exodeviation, near exodeviation, and NDD was statistically indifferent among the three groups. However, each procedure has its specific postoperative concerns, which should be considered before implementing in patients with CI-X(T).

Long-term outcomes of augmented unilateral recess-resect procedure in children with intermittent exotropia

BACKGROUND

Initial overcorrection after exotropia surgery has been considered as a desirable result. Recently, there had been several studies that reported better surgical results of augmented bilateral lateral rectus muscle recession procedure over the conventional procedure.

OBJECTIVES

To compare the long-term results of augmented unilateral lateral rectus recession-medial rectus resection procedure (RR) with the original surgery in exotropic children.

DATA EXTRACTION

A retrospective cohort study was performed on a total of 121 children with exotropia who underwent RR from February 2005 to December 2012 and were followed-up for at least 24 months. In 64 patients, RR was performed based on the original surgical table (original RR group). In 57 patients, the amount of medial rectus muscle resection was increased by 1 mm (augmented RR group).

RESULTS

In the original RR group, 47 of 64 patients (73.4%) had a successful outcome, 13 patients (20.3%) had recurrence, and 4 patients (6.3%) had overcorrection at 2 years after surgery. In the augmented RR group, 45 of 57 patients (79.0%) were successful, 4 patients (7.0%) had recurrence and 8 patients (14.0%) had overcorrection at 2 years after surgery. The recurrence rate was significantly lower in the augmented RR group than the original RR group, whereas the overcorrection rate was not significantly different between two groups at 2 years after surgery (P = 0.036 and P = 0.153, respectively). The cumulative probability of recurrence was lower in the augmented group at 36 months after surgery (P = 0.046, log rank test).

CONCLUSIONS

The long-term success rate of augmented RR in exotropic children was 79.0% and the recurrence rate was significantly lower than original RR with comparable overcorrection rates. Augmented RR can be considered as an alternative procedure in children with basic and convergence insufficiency type exotropia.

Adjustable surgical treatment of adult exotropia: postoperative target angles and surgical success

OBJECTIVES

This study had 3 objectives: (i) to characterize clinical profiles of adults with consecutive exotropia (CXT), intermittent exotropia (IXT), and sensory exotropia (SXT); (ii) to correlate immediate postoperative target angles with successful long-term ocular alignment; and (iii) to compare the efficacy of adjustable versus nonadjustable medial rectus resection ± advancement.

STUDY DESIGN

Retrospective, observational, and interventional cohort study.

PARTICIPANTS

A total of 133 adult exotropic patients treated surgically at 3 different hospitals between July 2012 and June 2013.

METHODS

The patients were divided according to clinical profiles (CXT, IXT, and SXT) based on ophthalmic and orthoptic assessments. Two treatment groups were established: group I-adjustable medial rectus resection ± advancement and adjustable lateral rectus recession; group II-nonadjustable medial resection ± advancement and adjustable lateral rectus recession. Measurements of immediate postadjustment alignment (target angle) and 4-6 months of follow-up alignment were performed and compared between groups. Surgical success was defined as distance primary position alignment within 10 prism diopters (PD) of orthotropia 4-6 months postoperatively.

RESULTS

Comparison of clinical profile groups showed that CXT patients had more hyperopia and amblyopia and smaller preoperative deviations; IXT patients had more diplopia and larger preoperative deviations (near > distance); and SXT patients had poor vision in the deviating eye and larger preoperative deviations. Immediate postoperative alignment was 5.2 PD of esodeviation in group I and 3.2 PD of esodeviation in group II. Overall success rates for ocular alignment at 4-6 months postoperatively were comparable with both surgical techniques (74.6% for group I and 74.3% for group II). Patients with a preoperative deviation ≥40 PD had a lower surgical success rate (63.8%) than patients with a deviation <40 PD (80%). Patients presenting with a significant (-1 or worse) abduction deficit in the operated eye at their first visit after surgery had a better success rate at 4-6 months' follow-up (83.3% vs 67.8%).

CONCLUSIONS

Adjustable and nonadjustable medial rectus surgeries seem equally successful. Creation of an abduction deficit in the early postoperative period seems predictive of a better outcome. Larger preoperative angles (≥40 PD) were associated with more exotropic drift and a lower percentage of surgical success. Future studies will continue to search for surgical strategies and the ideal target angle that will produce the best long-term alignment stability.

Predictive Factors Affecting Long-Term Outcome of Unilateral Lateral Rectus Recession

Background

There are few long-term outcome reports of unilateral lateral rectus (LR) recession for exotropia including a large number of subjects. Previous reports on unilateral LR recession commonly show extremely low rates of initial overcorrection and large exodrifts after surgery suggesting that the surgical dose may be increased. However, little is known of the long-term outcome of a large unilateral LR recession for exotropia.

Objectives

To determine long-term outcomes and predictive factors of recurrence after a large unilateral LR recession in patients with exotropia.

Data Extraction

Retrospective analysis was performed on 92 patients aged 3 to 17 years who underwent 10 mm unilateral LR recession for exotropia of ≤ 25 prism diopters (Δ) with prism and alternate cover testing and were followed up for more than 2 years after surgery. Final success rates within 10Δ of exophoria/tropia and 5Δ of esophoria/tropia at distance in the primary position, improvement in stereopsis and the predictive factors for recurrence were evaluated.

Results

At 24 months after surgery, 54% of patients had ocular alignment meeting the defined criteria of success, 45% had recurrence and 1% had overcorrection. After a mean follow-up of 39 months, 36% showed success, 63% showed recurrence and 1% resulted in overcorrection. The average time of recurrence was 23.4±14.7 months (range, 1–60 months) and the rate of recurrence per person-year was 23% after unilateral LR recession. Predictive factors of recurrence were a larger preoperative near angle of deviation (>16Δ) and larger initial postoperative exodeviation (>5Δ) at distance.

Conclusions

Long-term outcome of unilateral LR recession for exotropia showed low success rates with high recurrence, thus should be reserved for patients with a small preoperative near angle of exodeviation.

Advances in surgery procedures for convergence insufficiency-type intermittent exotropia

Intermittent exotropia with convergence insufficiency is defined as a greater exodeviation measured at near than at distance of at least 10 prism diopters and it is harmful to binocular vision at earlier time. This paper mainly introduces three operation patterns including lateral rectus recession(s) with or without a slanting procedure, unilateral lateral rectus recession with medial rectus resection, and medial rectus resection(s) with or without a slanting procedure.