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

A pilot randomized clinical trial comparing muscle transplant versus hang back recession in extra-large angle exotropia

PURPOSE

For extra-large angle exotropia (>60 prism diopters, PD), single-setting surgical alternatives are scarce; frequently, more than two muscle or two eye procedures are indicated. To evaluate the viability of single eye surgery, a current randomized comparative trial is undertaken.

METHODS

Twenty adult patients with extra-large angle exotropia underwent a thorough orthoptic evaluation before being divided into two groups at random. Ten patients in group 1 underwent medial rectus resection (5.5-7.5 mm), followed by transplant-aided lateral rectus recession (effective length: 4-5.5 mm) (9 mm). In group two, ten different patients underwent medial rectus resection (5.5-7 mm), but this time, the lateral rectus recession (9 mm) was aided with a hang-back suture (5-7 mm). The two procedures were compared at baseline and six months post-operatively.

RESULTS

There was no significant difference in the groups' median ages (P = .95). In groups one and two, the median corrections achieved were 81.00 (79.50-85.50) PD and 81.00 (79.75-86.50) PD, respectively. The differences in corrections were statistically insignificant (p = .99). In all patients, abduction limitation was frequently noted in the immediate post-operative period, which improved over time. In each group, there were two patients (>90 prisms) with residual deviation of at least 30 PD, for which the contralateral eyes were operated.

CONCLUSIONS

The hang-back recession was as successful as muscle transplant procedure in correcting 80-90 PD of exotropia with notable clinical benefits and ease.

Risk of consecutive esotropia after surgery for intermittent exotropia according to passive duction force

PURPOSE

To determine the relationship between consecutive esotropia (ET) and passive duction force (PDF) in patients with intermittent exotropia (XT).

METHODS

The study enrolled 70 patients in whom PDF was measured under general anesthesia prior to XT surgery. The preferred eye for fixation (PE) and the nonpreferred eye for fixation (NPE) were determined using a cover-uncover test. The patients were subdivided into two groups according to the angle of deviation at 1 month postoperation: (1) consecutive ET (CET group), >10 prism diopters (PD) of ET; and (2) non-CET (NCET group), ≤10 ET or residual exodeviation. The relative PDF of the medial rectus muscle (MRM) was obtained by subtracting the ipsilateral PDF of the lateral rectus muscle (LRM) from the PDF of the MRM.

RESULTS

The PDFs for the LRM in the PE in the CET and NCET groups were 47.28 g and 58.59 g, respectively (p = 0.147), and 56.18 g and 46.59 g for the MRM (p = 0.11), and in the NPE were 59.84 g and 55.25 g, respectively, for the LRM (p = 0.993), and 49.12 g and 50.53 g, respectively, for the MRM (p = 0.81). However, in the PE, the PDF in the MRM was larger in the CET group than in the NCET group (p = 0.045), which was positively associated with the postoperatively overcorrected angle of deviation (p = 0.017).

CONCLUSIONS

An increased relative PDF in the MRM in the PE was a risk factor for consecutive ET after XT surgery. Quantitative evaluation of the PDF could be considered when planning strabismus surgery to achieve the desired surgical outcome.

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 of horizontal muscle transposition and Inferior oblique weakening combined with horizontal surgery in V-pattern exotropia

Purpose

The objective of this study was to compare the effects of horizontal muscle transposition and inferior oblique weakening combined with horizontal surgery performed for V-pattern exotropia (XT) and to determine the most successful approach.

Methods

In our retrospective study, 52 patients who underwent horizontal surgery due to V-pattern XT and were followed up for at least 6 months were divided into two groups. Group 1 (n = 26) consisted of patients who underwent vertical transposition of the rectus muscles combined with horizontal surgery, and group 2 (n = 26) consisted of patients who underwent inferior oblique weakening combined with horizontal surgery. The two groups were compared before and after surgery in terms of visual acuity, refractive errors, deviation angles, pattern strabismus, fusion, stereopsis, over/under correction and surgical success.

Results

There was no difference between the two groups in terms of age, follow-up period, visual acuity, refractive errors, fusion or stereopsis. The amount of horizontal deviation was smaller in group 2 at the 1-6-month follow-ups. There was no difference between the two groups in terms of pattern collapse; however, the amount of pattern postoperatively was lower in group 2. The two groups were similar in terms of overcorrection; however, the undercorrection rate was higher in group 1. The surgical success rate was higher in group 2.

Conclusions

Inferior oblique weakening combined with horizontal surgery due to V-pattern XT was found to be superior to vertical transposition of the horizontal muscles in terms of surgical success and the amount of pattern postoperatively.

Dose-Response of Primary Bilateral Medial Rectus Resection in Infantile Exotropia

PURPOSE

To evaluate the dose-response relationship for primary bilateral medial rectus resection in children with exotropia, based on outcomes with this procedure.

METHODS

Dose-response at both distance and near were calculated as prism diopters correction per millimeter (PD/mm) of rectus resection. All surgeries were performed under general anesthesia through a fornix incision, using doubled-armed 6-0 polyglactin sutures. The resection amount ranged from 5 to 8 mm in each eye, according to the surgical dosage based on the largest angle of preoperative deviation.

RESULTS

The mean surgical dose-response for all procedures was 2.83 ± 1.03 PD/mm of resection at distance and near. The overall success rate was 53% at the final examination after a mean follow-up of 21.9 months. Patients with moderate angles (25 to 45 PD) had a higher success rate than those with 50 PD or greater deviation.

CONCLUSIONS

Primary bilateral medial rectus resection should be considered as a surgical alternative in childhood exotropia, particularly for moderate and constant deviations. [J Pediatr Ophthalmol Strabismus. 2022;59(1):24-27.].

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).

Evaluation of Efficacy and Lateral Gaze Incomitance in Symmetrical and Asymmetrical Surgery for Concomitant Esotropia and Exotropia

Purpose

Evaluation of asymmetrical and symmetrical horizontal strabismus surgery as regards efficacy and postoperative lateral gaze incomitance.

Patients and Methods

This prospective comparative interventional case series study included 40 patients of age more than 3 years with alternating horizontal strabismus. Patients were divided according to the type of horizontal deviation into esotropia and exotropia groups, which were further subdivided into asymmetrical and symmetrical subgroups in each type. The surgery was defined as symmetrical procedure if the surgery was done on the same muscle in the two eyes and it was defined as asymmetric in recess-resect procedures in one eye, and three horizontal muscles surgery. Preoperative and postoperative measurements were done in primary position, right, and left gaze using alternate prism cover test and hand-held orthopedic goniometer.

Results

At the end of follow-up period, a statistically insignificant difference (P value = 0.8057) was present in the success rate between the asymmetrical and symmetrical subgroups of esotropia (90 and 86.67%, respectively) and it was 100% in both exotropia subgroups. Lateral gaze incomitance results were different between esotropia and exotropia subgroups. In esotropia, a statistically significant difference was reported at 1 month (0.009), which became insignificant at 6 months (0.077) and 12 months (0.077) between asymmetrical and symmetrical subgroups. In exotropia subgroups, there was a statistically insignificant difference in lateral gaze incomitance at 1, 6, and 12 months (P = 1).

Conclusion

Asymmetrical procedure had the same efficacy and success rate of symmetrical procedure for the correction of concomitant horizontal deviations in primary gaze without persistent postoperative lateral gaze incomitance, especially in exotropia.

Clinical Trial Registration

NCT04199286.

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.

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.

Comparison of surgery versus observation for small angle intermittent exotropia

In young children with small angle exotropia, making decisions for the individual patient whether to perform surgery or not, and choosing the optimal time for surgical intervention are quite difficult. We aimed to compare the long-term outcomes of small angle intermittent exotropia of 20 prism diopters (PD) or less after observation versus strabismus surgery. A retrospective study was performed on 164 patients aged 3 to 13 who underwent surgical intervention or observation with or without conservative management for intermittent exotropia of 14 to 20 PD. The minimum follow-up period was 2 years. The average follow-up period was 3.9 ± 2.2 years in the observation group and 4.5 ± 2.3 years in the surgery group. At the final examination, the mean angle of deviation at distance was 11.1 ± 8.9 PD in the observation group and 9.0 ± 7.5 PD in the surgery group, which was not significantly different (P = 0.121). Changes in sensory outcome and fusional control were not significantly different between both groups (P = 0.748 and P = 0.968). Subgroup analysis including patients with poor fusional control also showed similar results. By multivariate analysis, the type of surgery, unilateral recess-resect procedure, was the only predictive factor of good motor outcome in the surgery group. In conclusion, long-term surgical outcomes in small angle exotropia did not appear to be more satisfying than observation in terms of motor and sensory outcomes.

Long-term outcomes of bilateral lateral rectus recession versus unilateral lateral rectus recession-medial rectus plication in children with basic type intermittent exotropia

PURPOSE

To compare the long-term surgical outcomes between bilateral lateral rectus recession (BLR) and unilateral lateral rectus recession-medial rectus plication (RP) in intermittent exotropia.

METHODS

Children who underwent BLR or RP for basic type intermittent exotropia between 2015 and 2016 with a minimum follow-up period of 2 years were retrospectively reviewed. Surgical outcomes were classified based on postoperative angle of deviation as follows: success (esodeviation ≤ 5 prism diopters [PD] to exodeviation ≤ 10 PD), and failure (overcorrection [esodeviation > 5 PD] and undercorrection or recurrence [exodeviation > 10 PD]).

RESULTS

Of 144 patients, 90 underwent BLR and 54 underwent RP. The angle of exodeviation of the RP group steadily increased over time after the surgery. The BLR group showed an earlier exodrift and a more stable course compared to the RP group. Kaplan-Meier survival analysis showed a better survival in the BLR group, with final success rates of 48.9% in the BLR group and 25.9% in the RP group after a mean follow-up of 2.2 years. Patients with a successful outcome had greater esodeviation at 1 week postoperatively (at distance 7.6 PD in the BLR group, 11.4 in the RP group).

CONCLUSIONS

Surgical outcomes were better in the BLR group than in the RP group. The RP group showed higher rates of recurrence of exodeviation, while the BLR group presented a more stable course. Establishing more esodeviation at postoperative week 1 in the RP group compared to the BLR group would be required to achieve successful results.

Comparison of surgical outcomes between bilateral recession and unilateral recession-resection in moderate-angle intermittent exotropia

PURPOSE

To compare postoperative drift after bilateral lateral rectus recession (BLR) and after unilateral recession combined with medial rectus resection (R&R) in children with primary moderate-angle intermittent exotropia.

METHODS

The medical records of children with intermittent exotropia in the range of 25^Δ-50^Δ who underwent BLR or R&R from July 2015 to September 2016 were reviewed retrospectively. Outcomes were classified according to postoperative angle of deviation at distance as overcorrection (esophoria or -tropia of >5^Δ), success (esophoria or -tropia of ≤5^Δ to exophoria/tropia of ≤10^Δ), or recurrence (exophoria or -tropia of >10^Δ). Patients were examined on postoperative day 1 and at 6 weeks, 6 months, and 12 months. Sensory status was evaluated using the Titmus stereoacuity test.

RESULTS

A total of 330 children were included (BLR, 175; R&R, 155). Exotropic drift was greater in the R&R group in the period between day 1 and 6 weeks and from 6 to 12 months (P <0.05). Surgical successful rates in each group were comparable: 57.7% in the BLR group and 60.6% in the R&R group (P > 0.05). However, higher overcorrection rates were noted in the BLR group at 6 and 12 months (16.6% vs 6.5 % at 12 months [P = 0.003]). There were more patients with deteriorated stereopsis after surgery in the BLR group (P = 0.025).

CONCLUSIONS

In our study cohort, BLR was associated with more stable long-term ocular alignment and a higher rate of overcorrection than R&R. Postoperative day 1 overcorrection of <16^Δ following R&R and of <10^Δ following BLR were associated with relatively good results.

Survival analysis of adult and children intermittent exotropia using a matched case-control design

To compare the surgical outcomes of adult intermittent exotropia (X(T)) patients and matched control children X(T) patients including survival analysis. Fifty-two adult X(T) patients and 129 matched control children X(T) patients were included. Clinical characteristics, survival analysis, and surgical dose-response curves were evaluated and compared between the two groups. The weighted Cox proportional hazards regression analysis was used in order to find risk factors for the recurrence. Using Kaplan-Meier survival analysis, the cumulative probability of survival rate considering recurrence as event of Adult group were 93.97% for one year, and maintained at 88.44% for two, three. four, and five years after surgery. In contrast, those of the Child group were 83.6%, 76.5%, 65.6%, 56.23%, and 40.16% for one, two, three, four, and five years after surgery, respectively. The Adult group had a better event-free survival curve than the Child group as analyzed by a Log-rank test (p = 0.020). According to multivariate weighted Cox regression analysis, the younger age at operation and the larger preoperative angle were significant risk factors for recurrence.

Surgical outcomes of unilateral recession and resection in intermittent exotropia according to forced duction test results

PURPOSE

To compare the surgical outcomes of unilateral lateral rectus recession-medial rectus resection (RR) according to forced duction test (FDT) results with those of conventional RR in intermittent exotropia.

METHODS

A total of 129 patients aged 3 to 10 years with intermittent exotropia who underwent RR between 2006 and 2011 were included. The operator compared the tension of the lateral rectus (LR) between both eyes. When FDT results were asymmetric, RR was performed on the eye with more LR tension. RR was performed on the nondominant eye when FDT results were symmetric. Patients were divided into two groups; one group (n = 64) underwent RR without FDT (RR group) and the other group (n = 65) underwent RR considering FDT results (RR-FDT group). Success, recurrence, reoperation rates and cumulative probabilities of success were evaluated in both groups. Surgical outcome was considered satisfactory if the distance deviation in the primary position was between ≤ 10 PD of exophoria/tropia and ≤ 10 PD of esophoria/tropia. Recurrence was defined as an alignment of > 10 PD of exophoria/tropia, and overcorrection defined as > 10 PD of esophoria/tropia. Reoperation for recurrence was recommended for constant exotropia ≥ 14 PD at distance.

RESULTS

The total follow-up periods were 4.4±2.3 years in the RR group, and 3.9±2.0 years in the RR-FDT group (P = .310). In the RR group, 50 patients (78.1%) were successful, 13 patients (20.3%) had recurrence, and 1 patient (1.6%) had overcorrection at 2 years after surgery. In the RR-FDT group, 58 patients (89.2%) were successful, 5 patients (7.7%) had recurrence, and 2 patients (3.1%) were overcorrected. The recurrence rate at 2 years after operation was significantly lower in the RR-FDT group (P = .045). Recurrence rates during the follow-up period were 5.6% per person-year in the RR group and 2.7% per person-year in the RR-FDT group. Reoperation for recurrence was performed on 7 patients (10.8%) in the RR-FDT group and 16 patients (25.0%) in the RR group (P = .035). Postoperative sensory outcomes were similar between both groups.

CONCLUSIONS

The forced duction test was useful in reducing the risk of recurrence at 2 years after surgery when RR was performed on the eye with more passive tension of the LR. Intraoperative FDT may be considered to choose which eye to operate on when planning RR in intermittent exotropia.

Factors affecting residual exotropia after two muscle surgery for intermittent exotropia

AIM

To study the factors affecting residual exotropia (>10 PD) at 4-6wk postoperative visit following two rectus muscle surgery for intermittent exotropia [bilateral lateral rectus (LR) recession or unilateral recess resect procedure].

METHODS

A retrospective chart review of patients with intermittent exotropia ≤50 PD who underwent two rectus muscle surgery in between Jan. 2011 to Dec. 2013 was performed. Possible factors were compared between patients with residual exotropia (>10 PD) and successful outcome (within 10 PD of orthotropia) at the 4-6wk postoperative visit. Effect/dose ratio was calculated by dividing the effect of surgery by the total amount (mm) of muscle surgery done.

RESULTS

One hundred and fifty-seven patients with mean age of 14y (range 3-53y) were included. Twenty-seven patients (17.2%) had residual exotropia at 4-6wk postoperative follow up. Age at surgery (P=0.009) and preoperative deviation for distance (P≤0.001) and near (P=0.001) were identified as important predictors of unsuccessful outcome. The occurrence of residual exotropia was not affected by amblyopia, anisometropia, lateral incomitance, pattern deviation, vertical deviation, type of exotropia or type of surgery done (recess-resect or bilateral LR recession). The effect/dose ratio was more in deviations >40 PD in the both recess-resect and bilateral LR recession type of surgery. The effect/dose ratio was less in patients with residual exotropia as compared to the successful outcome group (1.36 PD/mm vs 2.05 PD/mm in the bilateral LR recession surgery and 1.93 PD/mm vs 2.63 PD/mm in the unilateral recess-resect surgery).

CONCLUSION

Residual exotropia is seen in 17% of patients after two muscle surgery for intermittent exotropia. Patients with older age and larger preoperative deviation have greater chances of developing failure of two muscle strabismus surgery for intermittent exotropia.

A chronicle of surgical thinking and doing for exotropia: innovations and rediscoveries

PURPOSE

To review the evolution of theories and practices concerning surgery for exotropia over the last approximately 200 years.

METHODS

Major ophthalmology texts and relevant references were reviewed to discover experience and thinking concerning the causes of comitant intermittent and constant exotropia and corrective surgical approaches.

RESULTS

The concept that excessive divergence is the cause of comitant exotropia has given way to one recognizing that this disorder is a position of rest modified by convergence. Some operations discarded as unreliable or dangerous remain so today. Others continue to be well accepted, whether or not relating to advances in understanding of this condition. Several procedures practiced at former times have regained popularity.

CONCLUSIONS

Concern for the characteristics of extraocular muscle structure and function has led to surgical thinking that goes beyond consideration only of direction and magnitude of deviation. Sophisticated devices now provide heretofore unavailable information consistent with this new approach. The history of progress in surgery for exotropia is mixed. Although some procedures now employed are new, others currently in favor had been well known and formerly utilized by ophthalmologists for many decades. These should be regarded as rediscoveries or revivals rather than as novel. This review also suggests a need to address how to better report retrospective studies.

Outcome of two-muscle surgery for large-angle intermittent exotropia in children

BACKGROUND/AIMS

To evaluate the surgical outcomes of two-muscle surgery for childhood intermittent exotropia comparing large angles with moderate angles.

METHODS

We retrospectively reviewed the medical records of 178 children who had undergone bilateral lateral rectus recession (BLR) or unilateral recess-resect (RR) for large-angle (≥40 prism dioptres (PD); group A) or moderate-angle (≥20 and <30 PD; group B) intermittent exotropia with a postoperative follow-up period of 6 months or more. The main outcome measures were postoperative deviation angle and surgical success rate, and the secondary outcome measure was effect/dose ratio. The effect/dose ratio was defined as the corrected angle of deviation at postoperative 6 months divided by the sum of the amount of lateral rectus recession in each eye in BLR and by the sum of the amount of lateral rectus recession and medial rectus resection in RR. Surgical success was defined as alignment between 10 PD of exodeviation and 5 PD of esodeviation both at distance and at near.

RESULTS

There was a significant difference in mean angle of deviation at distance throughout the postoperative period (p<0.05). The final surgical success rate was significantly lower in group A than in group B (p<0.05). The effect/dose ratio for both BLR and unilateral RR was significantly greater in group A than in group B (p<0.05).

CONCLUSIONS

The patients with childhood intermittent exotropia with large angles showed significantly higher rates of undercorrection, though they also showed greater effects of BLR or RR per millimetre (the effect/dose ratio), compared with moderate-angle exotropia.

Comparison of Long-term Surgical Outcomes Between Unilateral Recession and Unilateral Recession-Resection in Small-Angle Exotropia

PURPOSE

To compare the surgical outcomes of unilateral lateral rectus recession-medial rectus resection (RR) and unilateral lateral rectus recession (ULR) for intermittent exotropia of ≤20 prism diopters (PD).

DESIGN

Retrospective, nonrandomized clinical study.

METHODS

A total of 130 children with intermittent exotropia of ≤20 PD who underwent unilateral RR or ULR of 10 mm were included. Patients were observed for at least 2 years. Success rates, cumulative probabilities of success, and factors related to recurrence and overcorrection were evaluated.

RESULTS

The mean follow-up duration after surgery was 3.1 ± 1.0 years in the RR group and 3.6 ± 1.6 years in the ULR group. In the RR group, 38 of 61 patients (62%) had ocular alignment within 10 PD of exophoria/tropia and 5 PD of esophoria/tropia; 18 patients (30%) had recurrence, and 5 (8%) had overcorrection. In the ULR group, 26 of 69 patients (38%) had successful alignment, 41 patients (59%) had recurrence, and 2 patients (3%) were overcorrected. At 6 months after surgery, the success rate was significantly higher in the ULR group (RR 61%; ULR 78%, P = .039), but it became comparable after 2 years (RR 60%; ULR 52%, P = .370). At the final examination after a mean duration of 3 years, the recurrence rates were lower in the RR group (30% vs 59%, P = .001), and the overcorrection rates were comparable (8% vs 3%, P = .252).

CONCLUSION

Unilateral RR resulted in more successful alignment and lower recurrence compared to ULR for the treatment of small-angle intermittent exotropia of ≤20 PD.

Long-Term Surgical Outcomes of Augmented Bilateral Lateral Rectus Recession in Children With Intermittent Exotropia

PURPOSE

To compare the long-term surgical outcomes of augmented bilateral lateral rectus (LR) recession with original surgery.

DESIGN

Retrospective, nonrandomized clinical study.

METHODS

A total of 447 children with ≤35 prism diopters (PD) of basic and divergence excess-type intermittent exotropia, who underwent original bilateral LR recession based on the largest angle measured at distance and near, or augmentation surgery with the surgical dosage augmented by 1.0-1.5 mm more than the original formula were included. Patients were observed for at least 2 years. Success rates, cumulative probabilities of success, factors related to recurrence, and overcorrection were evaluated.

RESULTS

At a mean follow-up of 4.0 years, 48 of 101 patients (48%) undergoing original surgery maintained successful alignment within 10 PD of exophoria/tropia and 5 PD of esophoria/tropia; 49 (49%) had recurrence, and 3 (3%) had overcorrection. After augmented surgery, 203 of 346 patients (59%) were successfully aligned, 129 (37%) had recurrence, and 14 (4%) had overcorrection. Augmented surgery showed higher long-term successful alignment rates (P= .047) and lower recurrence rates compared to original surgery (P = .042) and the overcorrection rate was similar between the 2 groups (P= .774). Patients with divergence excess type showed higher cumulative success rates compared to that of the basic type (P = .010) after augmented surgery.

CONCLUSION

Augmented bilateral LR recession resulted in more successful alignment and lower recurrence without higher overcorrection compared to the original surgery for the children with intermittent exotropia. Augmentation of the original table should be considered when planning bilateral LR recession, especially in patients with divergence excess-type exotropia.

Single Stage Surgical Outcomes for Large Angle Intermittent Exotropia

Although there were many prior studies about exotropia, few focused on large-angle intermittent exotropia. The goal of this study was to evaluate single-stage surgical outcomes for large-angle intermittent exotropia and analyze risk factors that may affect the success of surgery. Records from intermittent exotropia patients with exodeviations >60 prism diopters(PD) who were surgically treated at the Zhongshan Ophthalmic Center, of Sun Yat-Sen University were reviewed. Included within this review were data on, pre- and post-operative ocular motility, primary alignment, binocular vision and complications. Patients with exodeviations ≤70PD received two-muscle surgery, while those with exodeviations >70PD were subjected to a three-muscle procedure. A total of 40 records were reviewed. The mean exodeviation was 73±9PD at distance and 75±26PD at near. There were 25 patients received two-muscle surgery and 15 the three-muscle procedure. Orthophoria (deviation within 8PD) was obtained in 77.5% of these patients and the ratios of surgical under-correction and over-correction were 15% and 7.5% respectively. However, when combining ocular alignment with binocular vision as the success criteria, success rates decreased to 30%. No statistically significant differences in success rates were obtained between the two- and three-muscle surgery groups. Seven subjects experienced an abduction deficit during the initial postoperative stages, but eventually showed a full recovery. One patient required a second surgery for overcorrection. No statistically significant risk factors for poor outcome were revealed. Our data showed that single-stage two- and three-muscle surgeries for large-angle intermittent exotropia are effective in achieving a favorable outcome.

Long-term surgical outcomes and factors for recurrence after unilateral lateral rectus muscle recession

AIM

To evaluate long-term surgical outcomes and risk factors for recurrence after unilateral lateral rectus muscle recession (ULR) in children with small to moderate angle intermittent exotropia (IXT).

METHODS

214 patients with basic type IXT of 15-24 prism dioptres (PD) who underwent ULR were included. The main outcome measure was success rate at 2 years after surgery and at final follow-up. The risk factors related to recurrence were evaluated using univariable and multivariable logistic regression analyses.

RESULTS

Success rate at postoperative 2 years was 92.5% and at final examination after a mean follow-up of 3.9 years was 83.2%. No overcorrection was observed. Preoperative exodeviation of 20-24 PD was the significant risk factor for recurrence according to both univariable (OR=3.577, p=0.022) and multivariable analysis (OR=3.265, p=0.034).

CONCLUSIONS

The overall long-term successful alignment rate of ULR for 15-24 PD of IXT was good. However, patients with 20-24 PD of IXT showed worse prognosis compared with 15-19 PD of IXT.

Comparison of Surgical Outcomes with Unilateral Recession and Resection According to Angle of Deviation in Basic Intermittent Exotropia

Purpose

The purpose of this study is to compare the surgical outcomes and near stereoacuities after unilateral medial rectus (MR) muscle resection and lateral rectus (LR) recession according to deviation angle in basic intermittent exotropia, X(T).

Methods

Ninety patients with basic type X(T) were included in this study. They underwent unilateral recession of the LR and resection of the MR and were followed postoperatively for at least 12 months. Patients were divided into three groups according to their preoperative deviation angle: group 1 ≤20 prism diopter (PD), 20 PD< group 2 <40 PD, and group 3 ≥40 PD. Surgical outcomes and near stereoacuities one year after surgery were evaluated. Surgical success was defined as having a deviation angle range within ±10 PD for both near and distance fixation.

Results

Among 90 patients, groups 1, 2, and 3 included 30 patients each. The mean age in groups 1, 2, and 3 was 9.4 years, 9.4 years, and 11.0 years, respectively. The surgical success rates one year after surgery for groups 1, 2, and 3 were 80.0%, 73.3%, and 73.3% (chi-square test, p = 0.769), respectively. The undercorrection rates for groups 1, 2, and 3 were 16.7%, 23.3%, and 26.7%, and the overcorrection rates were 3.3%, 3.3%, and 0%, respectively. The mean preoperative near stereoacuities for groups 1, 2, and 3 were 224.3 arcsec, 302.0 arcsec, and 1,107.3 arcsec, and the mean postoperative near stereoacuities were 218.3 arcsec, 214.7 arcsec, and 743.0 arcsec (paired t-test; p = 0.858, p = 0.379, p = 0.083), respectively.

Conclusions

In basic X(T) patients, the amount of angle deviation has no influence on surgical outcomes in unilateral LR recession and MR resection. The near stereoacuities by one year after LR recession and MR resection for intermittent X(T) were not different among patient groups separated by preoperative deviation angle.

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.