The Stabilization of Postoperative Exo-drift in Intermittent Exotropia after Surgical Treatment

Impact of Online Video Game-Based Dichoptic Training on Binocular Vision Rehabilitation in Post-surgical Patients with Intermittent Exotropia

INTRODUCTION

Dichoptic training has emerged as a promising rehabilitation approach for improving binocular visual function in patients with strabismus. A prospective observational study design was employed to assess the effectiveness of online video game-based dichoptic training in rehabilitating binocular visual function in patients who had undergone an operation for intermittent exotropia.

METHODS

A total of 64 patients who had undergone an operation for intermittent exotropia were recruited and divided into the training group and the control group based on whether they would receive the dichoptic training. The dichoptic training was conducted for 3 months in the training group and the control group would not accept any form of orthoptic therapy. Assessments of binocular visual functions and deviation were conducted at baseline, 3-month and 6-month follow-up.

RESULTS

Twenty-nine participants in the training group (mean 9.69 ± 2.66 years old) and 26 participants in the control group (mean 8.41 ± 2.64 years old) completed follow-up. At both 3- and 6-month follow-ups, the training group showed superior distance stereopsis compared to the control group, with near stereopsis only showing significant difference at the 6-month follow-up. Additionally, the training group exhibited significantly less distance exo-deviation drift than the control group at these times, and no significant difference was observed in near exo-deviation drift between the groups. The control group had a significantly higher rate of suboptimal surgical outcomes at both the 3- and 6-month follow-up. However, no significant differences were observed in simultaneous perception and fusion functions between the two groups.

CONCLUSIONS

Online video game-based dichoptic training has the potential to become a novel postoperative rehabilitation strategy for patients with intermittent exotropia.

Analysis of postoperative exodrift according to surgical methods for intermittent exotropia

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Impact of Vision Impairment and Ocular Morbidity and Their Treatment on Quality of Life in Children: A Systematic Review

TOPIC

This review summarizes existing evidence of the impact of vision impairment and ocular morbidity and their treatment on children's quality of life (QoL).

CLINICAL RELEVANCE

Myopia and strabismus are associated with reduced QoL among children. Surgical treatment of strabismus significantly improves affected children's QoL.

METHODS

We conducted a systematic review and meta-analysis by screening articles in any language in 9 databases published from inception through August 22, 2022, addressing the impact of vision impairment, ocular morbidity, and their treatment on QoL in children. We reported pooled standardized mean differences (SMDs) using random-effects meta-analysis models. Quality appraisal was performed using Joanna Briggs Institute and National Institutes of Health tools. This study was registered with the International Prospective Register of Systematic Reviews (identifier, CRD42021233323).

RESULTS

Our search identified 29 118 articles, 44 studies (0.15%) of which were included for analysis that included 32 318 participants from 14 countries between 2005 and 2022. Seventeen observational and 4 interventional studies concerned vision impairment, whereas 10 observational and 13 interventional studies described strabismus and other ocular morbidities. Twenty-one studies were included in the meta-analysis. The QoL scores did not differ between children with and without vision impairment (SMD, -1.04; 95% confidence interval [CI], -2.11 to 0.03; P = 0.06; 9 studies). Myopic children demonstrated significantly lower QoL scores than those with normal vision (SMD, -0.60; 95% CI, -1.09 to -0.11; P = 0.02; 7 studies). Children with strabismus showed a significantly lower QoL score compared with those without (SMD, -1.19; 95% CI, -1.66 to -0.73; P < 0.001; 7 studies). Strabismus surgery significantly improved QoL in children (SMD, 1.36; 95% CI, 0.48-2.23; P < 0.001; 7 studies). No randomized controlled trials (RCTs) concerning refractive error and QoL were identified. Among all included studies, 35 (79.5%) were scored as low to moderate quality; the remaining met all quality appraisal tools criteria.

DISCUSSION

Reduced QoL was identified in children with myopia and strabismus. Surgical correction of strabismus improves the QoL of affected children, which supports insurance coverage of strabismus surgery. Further studies, especially RCTs, investigating the impact of correction of myopia on QoL are needed.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Comparison of Unilateral Versus Bilateral Lateral Rectus Recession for Small Angle Intermittent Exotropia: Outcomes and Surgical Dose-Responses

PURPOSE

To compare the surgical outcomes of unilateral lateral rectus recession to bilateral lateral rectus recession for small angle intermittent exotropia.

METHODS

This was a retrospective cohort study of pediatric patients with an intermittent exotropia between 16 and 20 prism diopters (PD) who underwent unilateral lateral rectus recession or bilateral lateral rectus recession at a single tertiary care pediatric hospital. The primary outcome was success (exotropia < 10 PD of esotropia < 5 PD, no decrease in stereopsis > 0.6 log arcsec, and no reoperation) at 12 months postoperatively. Secondary outcomes included survival analysis of time to surgical failure, surgical dose-response, and improvement in central fusion or stereopsis.

RESULTS

At 12 months, successful outcomes were achieved in 13 of 27 patients (46%) in the bilateral lateral rectus recession group and 19 of 28 patients (70%) in the unilateral lateral rectus recession group, which was not a statistically significant difference (P = .10). Survival analysis showed a trend toward a higher rate of failure in the bilateral lateral rectus recession group compared to the unilateral lateral rectus recession group (P = .04). The mean surgical dose-response was 1.7 PD/mm at 1 week and 1.0 PD/mm at 12 months for the bilateral lateral rectus recession group, and 2.0 PD/mm at 1 week postoperatively and 1.4 PD/mm at 12 months postoperatively for the unilateral lateral rectus recession group. There were no cases of long-term postoperative lateral incomitance in either group.

CONCLUSIONS

Unilateral lateral rectus recession and bilateral lateral rectus recession have similar success rates for small angle intermittent exotropia after at least 12 months of follow-up. Randomized controlled trials in surgical management of intermittent exotropia should consider unilateral lateral rectus recession as a treatment arm. [J Pediatr Ophthalmol Strabismus. 2022;59(5):350-355.].

Effects of orthoptic therapy in children with intermittent exotropia after surgery: study protocol for a randomized controlled trial

Background

Intermittent exotropia (IXT) is the most common type of exotropia in China. Surgery is usually required to align the eye deviation to maintain or obtain better binocular visual function. However, there is a high rate of exodrift or recurrence in surgically treated patients. Orthoptic therapy is sometimes recommended for IXT patients after surgery. However, there is a lack of high-quality randomized controlled trials to prove that orthoptic therapy could be an effective supplement to surgical treatment for IXT patients. The main purpose of this study is to test the clinical effectiveness of orthoptic therapy in long-term stabilization of postoperative IXT patient. This report describes the design and methodology of the Intermittent Exotropia Postoperative Treatment Clinical Trial, which is the first large-sample, blank-controlled, randomized clinical trial.

Methods

A total of 136 IXT patients (aged 7 to 17 years) will be enrolled and assigned to the orthoptic therapy group or blank control group according to a simple randomization scheme. Patients in the orthoptic therapy group will receive at least 2 months of orthoptic therapy, such as anti-suppression, vergence, and accommodation training. Patients in the blank control group will receive only refractive correction. All enrolled patients will need regular follow-up observation until 24 months after surgery. The primary outcome will be the proportion of participants meeting suboptimal surgical outcomes in this 24-month follow-up, which is defined as (1) exodeviation of 10 prism diopters (PD) at distance or near using the simultaneous prism and cover test (SPCT) or (2) loss of 2 or more octaves of stereoacuity from baseline, at any masked follow-up visit examination. The secondary outcomes will be the exodeviation at distance and near using the simultaneous prism and alternate cover test (PACT), magnitude of fusional convergence, stereoacuity, and accommodation. Measurements will be taken at baseline and at the 6-, 12-, 18-, and 24-month follow-ups.

Discussion

To the best of our knowledge, this will be the first prospective, randomized controlled study of orthoptic training in IXT patients after surgery. The aim of this work is to confirm the efficacy of orthoptic therapy in reducing the proportion of recurrence among IXT patients after surgery and improving binocular vision function.

Trial registration

Chinese Clinical Trial Registry ChiCTR1900026891. Registered on 25 October 2019.

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

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

Botulinum toxin injection without electromyographic guidance in consecutive esotropia

Purpose

To investigate the efficacy of botulinum toxin injection without electromyographic guidance for the treatment of consecutive esotropia.

Methods

A retrospective study was performed on 49 subjects with consecutive esotropia who received botulinum toxin injection in the medial rectus muscles without the use of electromyographic guidance. Treatment was considered successful if the final ocular alignment was orthotropic or esodeviation was ≤10 prism diopters (PD) during distant fixation.

Results

The mean age was 15.2 ± 8.3 years. The mean esodeviation before injection was 21.8 ± 9.1 PD at distance and 21.3 ± 8.3 PD at near. The mean number of injections per patient was 1.3 ± 0.7, and 46 patients (93.9%) received two or fewer injections. At 6 months after the final injection, the mean angle of esodeviation was 7.3 ± 6.0 PD at distance and 7.5 ± 6.6 PD at near (all p<0.001), and 69.4% showed successful alignment. By multivariate analysis, an initial postoperative esodeviation of ≤18 PD at one month after exotropia surgery was considered to be a predictive factor for successful botulinum toxin injection (P = 0.007). Vertical deviation and/or ptosis occurred in 4 patients (8.2%) at two weeks after injection, which all resolved within three months. There was no recurrence of exotropia up to the final follow-up examination.

Conclusion

Botulinum toxin injection without electromyographic guidance is safe and effective in the treatment of consecutive esotropia without causing recurrent exotropia. Successful botulinum toxin injection is likely in patients with an initial postoperative esodeviation of 18PD or less at one month after exotropia surgery.

The stability of horizontal ocular alignment of triad exotropia after one-step triple surgery

PURPOSE

A-pattern exotropia, superior oblique muscle overaction, and dissociated vertical deviation may coexist and are referred to as triad exotropia. The present study evaluated the postoperative stability of horizontal ocular alignment of triad exotropia and possible prognostic factors.

METHODS

Medical records of patients with triad exotropia who had one-step triple surgery of superior oblique muscle weakening, superior rectus muscle recession, and lateral rectus muscle recession were reviewed. The horizontal alignment and postoperative drift of triad exotropia were analyzed and compared with constant exotropia.

RESULTS

The triad exotropia showed a mean of 7.7^△ (± 8.5^△) eso-drift, while the constant exotropia was (3.5^△ ± 3.4^△) exo-drift. Multiple linear regression analysis showed that the degree of superior oblique muscle overaction after surgery (P = 0.011) was the only factor associated with horizontal drift. Patients with superior oblique muscle underaction showed larger eso-drift when compared to patients without superior oblique muscle underaction (- 18.0^△ ± 11.1^△ vs. - 5.1^△ ± 5.7^△; P = 0.024). The final success rates of the triad exotropia and constant exotropia groups were 53.3% and 69.2%, respectively, and the overcorrection rates were 26.7% and 2.6% (P = 0.035).

CONCLUSIONS

An overall trend of eso-drift in primary position occurred in triad exotropia after triple surgery up to a follow-up of 25 months. Patients presenting superior oblique muscle underaction after surgery seemed to have large angles of eso-drift, which might be taken into account in surgical planning and follow-up.

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.

Relation between early postoperative deviation and long-term outcome after unilateral lateral rectus recession and medial rectus resection for adult exotropia

AIM

To evaluate the relationship between early postoperative deviation and long-term outcome after unilateral recession and resection surgery for adult exotropia, and to evaluate exotropic shift after surgery.

METHODS

This was a retroprospective study involving adult patients with exotropia who underwent unilateral recession and resection surgery and were followed up for at least 2y. The results were evaluated at 2y and the final visit. Factors influencing a successful outcome were analyzed. Early postoperative deviation at 1wk was used to evaluate relationship with long-term outcome. The long-term outcome was classified into 3 groups: successful, acceptable, and poor. Successful outcome was defined as a distance deviation between esodeviation 8 prism diopters (PD) and exodeviation 10 PD.

RESULTS

Forty-two patients were enrolled. The mean age at surgery was 26y (range, 15-49y). The median follow-up period was 30mo (range, 24-108mo). Successful outcome was found in 81% of patients at 2y and in 71% at the final visit. Overcorrection at 1wk postoperatively was associated with a successful outcome at 2y. Initial postoperative alignment between orthotropia and esodeviation of 8 PD had the highest chance of a successful outcome (RR=2.2). The mean postoperative exotropic drift was 4.7 PD at the first month and 9.3 PD at 2y.

CONCLUSION

Initial postoperative deviation can predict long-term outcome after unilateral recession and resection surgery for adult exotropia. The most desirable outcome at 1wk post-operatively was orthotropia to small esodeviation. Most patients have exotropic drift at a subsequent follow-up, especially in the first month after surgery.

Characteristics of Patients Who Are Not Responsive to Alternate Patching for Overcorrected Intermittent Exotropia

Purpose

To compare the characteristics of patients with surgically overcorrected intermittent exotropia treated with alternate patching.

Methods

The medical records of 51 patients who underwent bilateral lateral rectus muscle recession for intermittent exotropia and required alternate patching to correct postoperative overcorrection were retrospectively reviewed. Patients with postoperative esodeviation ≥18 prism diopters (PD) were started on alternate patching on postoperative day 1, whereas those with postoperative esodeviation of 10 to 17 PD were started after 2 weeks. Postoperative esodeviation <10 PD was considered as slight intentional overcorrection after exotropia surgery. Patients not responsive to alternate patching treatment were defined as those with postoperative esodeviation ≥10 PD after 3 months of treatment. Sex, family history, age, refractive error, amblyopia, stereopsis, suppression, type of exotropia, surgical method, preoperative and postoperative angle of deviation, and start time of alternate patching were compared.

Results

Among 51 patients, 29 patients responded to alternate patching and 22 patients did not respond. Female sex (p = 0.04), larger preoperative exodeviation at distance (p = 0.04), late onset of postoperative maximal esodeviation (p < 0.01), larger postoperative maximal esodeviation at near (p = 0.02), and late initiation of alternate patching (p = 0.01) were associated with patients in the non-responsive group. Although postoperative angle of deviation was similar for 2 weeks, the angle of postoperative esodeviation was significantly larger in the non-responsive group than in the responsive group, beginning at 1 month postoperatively.

Conclusions

Female sex, large preoperative exodeviation, late initiation of alternate patching, and large esodeviation 1-month postoperative predisposed patients to be resistant to alternate patching for postoperative overcorrection.

The fast exodrift after the first surgical treatment of exotropia and its correlation with surgical outcome of second surgery

Background

To compare the rate of exodrift after a second surgery for recurrent exotropia, in patients grouped to fast versus slow exodrift after their first surgery. To determine whether there is a correlation with surgical outcome, and to evaluate the factors associated with fast exodrift.

Methods

Patients with recurrent intermittent exotropia, who underwent contralateral lateral rectus recession and medial rectus resection as the second surgery and were followed up for 24 months postoperatively between January 1991 and January 2013, were reviewed retrospectively. The patients were divided into two groups according to the rate of exodrift after the first surgery: Group F, patients exhibiting fast exodrift after the first surgery (> 10 prism diopters [PD] before postoperative month 6); and Group S, patients exhibiting slow exodrift after the first surgery (≤10 PD before postoperative month 6). The difference in the clinical course over the 24 months after the second surgery between the two groups and factors associated with fast exodrift were analyzed.

Results

In total, 106 patients with recurrent exotropia were enrolled in this study. Of these, 68 (64.2%) and 38 (35.8%) patients were included in group F and S, respectively. Group F showed more exodrift compared with groups S over the 24-month postoperative period; however, there was no significant difference in the clinical course between the two groups during that time (p = 0.54, repeated-measure ANOVA). In logistic analysis, immediate postoperative deviation after the first surgery was associated with fast exodrift (p <  0.001).

Conclusion

Although patients with recurrent exotropia had shown fast exodrift after the first surgery, no significant difference in the surgical outcome was observed after the second surgery according to the rate of exodrift after the first surgery.