Predictors of surgical success in patients with intermittent exotropia

The effects of refractive status on the outcomes of strabismus surgery in patients with esotropia

BACKGROUND

The success of the strabismus surgery can hinge on several factors. One of these factors is refractive condition like hyperopia or myopia. Our study seeks to evaluate the surgical outcomes in patients with esotropia and myopia.

METHODS

This case-control study encompassed all surgical cases of esotropia at Torfe and Negah Hospital between 2016 and 2021, which satisfied our specified inclusion criteria. The initial variables from electronic medical records were collected, including demographic, clinical, and surgery-related factors. At the final follow-up appointment, the level of eye deviation, both at distance and near, was recorded. We considered the operation a "success" for patients with a post-surgery distance eye deviation of 10(Pd) or less. Patients with greater deviation were classified as surgery failure. Statistical analyses were executed using SPSS software (version 16.0), and a P-value less than 0.05 was considered significant.

RESULTS

Of the 194 patients evaluated, 112 were incorporated into the study. Surgical failure was observed in 14.29% of myopic patients, 29.79% of hyperopic patients, and 31.82% of emmetropic patients. The myopia group displayed a 0.19 odd ratio for surgical failure compared to the combined hyperopia and emmetropia groups, not statistically significant (OR: 0.19, CI 95%: 0.03-1.02). Additionally, patients diagnosed with Lateral Rectus Under-action were found to be 6.85 times more likely to experience surgery failure(OR: 6.85, CI 95%: 1.52-30.94). An elevated risk of surgical failure was also identified in patients who underwent Inferior Oblique Weakening procedure, indicated by a 3.77-fold increase in the odds ratio for failure(OR: 3.77, CI 95%: 1.08-13.17).

CONCLUSION

In our study, despite numerical disparities, there was no statistical difference among the success rates of all esotropia patients with different refractive errors. The patients with LRUA or IOOA showed lower success rates. Myopic patients had higher post-op overcorrection with lower reoperation rates compared to hyperopic or emmetropic patients.

Effectiveness of Strabismus Surgery in Intermittent Exotropia and Factors Influencing Outcome

Intermittent exotropia (IXT) is known to relapse after surgery. No factors to predict or prevent recurrence are known with certainty. This study investigated surgical outcome, potential influencing factors, and reoperation rate in patients with IXT. Medical records of 537 patients who underwent surgery for IXT from 2000 to 2022 with preoperative angles of exodeviation of 6 to 50 prism diopters (PD) were retrospectively studied. Multivariate regression analyses of factors influencing surgical outcome on postoperative day 1 (POD1) and reoperation rate were performed. A Kaplan-Meier analysis was performed to illustrate the reoperation rate. After the first surgery, 83.8% of patients had a successful surgical outcome on POD1 (esodeviation ≤ 5 PD or exodeviation ≤ 10 PD). Logistic regression analysis revealed that small preoperative angles of exodeviation increased the probability for surgical success. Follow-up data at different times (4 days-20 years) after surgery were available for 176 patients: 40 patients were still in the range of surgical success, 133 patients had exotropia > 10 PD. Of the follow-up patients, 65 (12.1%) underwent reoperation. A total of 8.5% had their reoperation within one year after the first surgery, 52.9% within five years. Cox regression analysis revealed that large preoperative angles of exodeviation, far/near incomitance and alphabet pattern strabismus increased the risk of reoperation. Most patients achieved surgical success on POD1, yet the squint angles often increased after surgery, resulting in reoperation in some patients. Prospective studies are needed for a better assessment of pre-, peri- and postoperative factors for surgical success in IXT.

Initial postoperative plasticity as a predictor of mid-term stereoacuity outcome after surgery for intermittent exotropia

BACKGROUND

Intermittent exotropia (IXT) would cause different degrees of damage to stereopsis. We aimed to introduce a visual perception plasticity score (VPPS) that reflects initial postoperative plasticity and evaluate its effectiveness in predicting the mid-term surgical outcome in IXT patients.

METHODS

A total of 149 patients with intermittent exotropia who underwent surgery in November 2018 and October 2019 were recruited. All subjects underwent detailed ocular examinations before and after surgery. VPPS were calculated based on visual perception examination system at one week postoperatively. Demographic, angle of deviation and stereopsis were collected and analyzed with regard to the VPPSs preoperatively and at one week, one month, three months, six months postoperatively. Predictive performances of VPPS were assessed using receiver operating characteristic (ROC) curves, the area under the curve (AUC) and cut-offs were obtained.

RESULTS

Of the 149 patients, the average deviation was 43^Δ at distance and 46^Δ at near. The average rate of normal stereopsis before surgery was 22.81% at distance and 29.53% at near. Higher VPPS was associated with preoperative better near stereoacuity (r = 0.362, p = 0.000), less angle of deviation at distance (r=-0.164, p = 0.046), and better near (r = 0.400, p = 0.000) and distant stereoacuity (r = 0.321, p = 0.000) during the early postoperative period (1 week). The areas under the curves suggested that VPPS could be an effective predictor of sensory outcome(AUC>0.6). Cut-off values of 50 and 80 were calculated for VPPS using ROC curve analysis.

CONCLUSION

Higher VPPSs were associated with a greater possibility of stereopsis improvement in patients with IXT. VPPS is a potentially promising indicator to predict the mid-term surgical outcome of intermittent exotropia.

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

PURPOSE

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

DESIGN

Prospective clinical cohort study.

METHODS

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

RESULTS

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

CONCLUSIONS

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

Quantitative Evaluation of Binocular Visual Perception in Patients With Strabismus: An Observational Study

PURPOSE

To quantitatively evaluate and compare binocular visual perception between normal individuals and patients with different types of strabismus using a binocular phase combination paradigm.

METHODS

A total of 117 participants were included in the study and were divided into the normal control group, exophoria group, comitant exotropia group, comitant esotropia group, and special strabismus group according to the type of strabismus. The effective contrast ratio (ECR) was measured to quantitatively evaluate binocular visual perception. Binocular fusion was evaluated using the Worth 4-dots flashlight. Stereoacuity was detected by the Titmus stereo test.

RESULTS

The mean ECRs in the normal control group, exophoria group, comitant exotropia group, comitant esotropia group, and special strabismus group were 0.896 ± 0.214, 0.824 ± 0.234, 0.520 ± 0.279, 0.261 ± 0.139, and 0.461 ± 0.243, respectively. Within-group differences in the ECR were statistically significant. In addition, there was no statistically significant difference between the normal control group and exophoria group, and the concomitant exotropia group and special strabismus group and the other groups were statistically significant in pairwise comparison. The binocular visual perception was basically balanced in the exotropia group and most imbalanced in the comitant esotropia group, followed by the comitant exotropia group and the special strabismus group. The results also indicated that the decreased ECR was related to poor stereopsis and ECR had a significant positive correlation with binocular fusion function.

CONCLUSIONS

Different types of strabismus have different degrees of visual perception imbalance. The binocular phase combination paradigm applied in this study can quickly and accurately quantify the degree of binocular visual perception imbalance in patients with strabismus by measuring ECR. [J Pediatr Ophthalmol Strabismus. 2023;60(2):120-130.].

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.

Comparison of Botulinum toxin type A with surgery for the treatment of intermittent exotropia in children

Background

The aim of this study was to observe the effectiveness of botulinum toxin type A (BTA) in the treatment of intermittent exotropia (IXT) in children compared with strabismus surgery.

Methods

One hundred forty-four children with a clear diagnosis of IXT and an indication for surgery were eligible for inclusion. Subjects were divided into two groups based on parental decision: the BTA injection group (injection group) or the conventional surgery group (surgery group). All cases were followed up for 6 months. The primary outcome was a comparison of the success rate (deviation between − 10 and + 10 PD) between the two groups at 6 months after the initial treatment. Secondary outcomes included change in deviation, visual function, and post-surgical complications.

Results

Seventy-two patients were enrolled in each group. At 6-month follow-up, there was no significant difference in the success rate between the injection and surgery groups (52.8% vs 66.7%, P = 0.13; postoperative deviation − 12.22 ± 10.80 PD vs − 9.17 ± 10.30 PD, P = 0.09). The binocular Visual function, except for near stereoacuity, improved after treatment in both groups, while the fusion recovery rate was higher in the surgical group (68.1% vs 95.8%, P < 0.001). Transient complications in the injection group included diplopia, ptosis, and subconjunctival hemorrhage, whereas subconjunctival hemorrhage, conjunctival edema, foreign body sensation, pain, and diplopia were seen in the surgical group. The complications of BTA were relatively mild.

Conclusions

BTA is as effective as surgery in the treatment of IXT in children, but the recovery of the fusion is lower than surgery.

Trial registration

The study has completed the clinical registration on (ChiCTR-INR-17013777).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02285-2.

Outcomes of intermittent exotropia surgery

PURPOSE

To study the epidemiological and clinical characteristics of intermittent exotropia and to describe our therapeutic choices as well as their results and prognostic factors.

MATERIALS AND METHODS

This was a retrospective study including 57 cases of intermittent exotropia. All patients underwent a complete ophthalmological examination with a sensory-motor assessment. Surgery was performed by the same surgeon, and the vertical component was addressed surgically at the same time as the exotropia. Statistical analysis was performed using SPSS software version 21.0.

RESULTS

Our patients were classified as basic exotropia in 46 cases (80.7%), divergence excess in eight cases (14.1%), and convergence insufficiency in three cases (5.2%). Amblyopia was found in 26% of cases. The preoperative maximum angle of deviation was 36.5DP±9.1DS and a vertical component was found in 16 patients (28%). The most common was V pattern (8 patients). The mean age at the time of surgery was 14.8 years old. After a single surgery, we obtained motor success in 78.9% of the patients. Three patients were re-operated, with an overall motor success of 84.2%.

CONCLUSIONS

Motor and sensory success may be achieved in intermittent exotropia. Rigorous, early management is necessary, even if tropic episodes are still rare. The rate of early consultation among children is still low in our country; thus, a national strabismus screening program must be established to obtain the best results.

Preoperative Variables Associated with Surgical Outcome for the Correction of Exodeviation

The success rate of exodeviation surgery in existing literature has been shown to be variable. This study sought to determine the success rate of surgery for exodeviation in Atlantic Canada and determine variables associated with surgical outcome. A retrospective chart review was performed, considering patients who had been assessed and surgically treated for exodeviation at the IWK Health Centre between 2011–2018. This study included 176 subjects, aged 1–75 years. Preoperative variables were compared between subjects with successful versus unsuccessful surgical outcomes, using the chi square, Fischer’s exact test and binary logistic regression. A success rate of 43% was determined. Smaller preoperative deviation size at near and distance fixation, as well as the basic type classification were associated with successful operative outcome. Left eye acuity showed a statistically significant association with surgical success outcome. In conclusion, these findings compliment those of previous groups, suggesting exodeviation surgery outcome is variable. Our results add to a growing list of variables implicated in outcomes for these subjects. A smaller deviation preoperatively was associated with success in existing data and in this study, and these findings may suggest a potential role for basic subtype into future exodeviation literature.

Surgery at early versus late for intermittent exotropia: a Meta-analysis and systematic review

AIM

To compare the outcomes between early surgery and late surgery for intermittent exotropia (IXT) with a Meta-analysis.

METHODS

Scientific databases including PubMed, Embase, Web of Science, Cochrane and China National Knowledge Infrastructure were searched prior to December 16, 2019. From this broad database search, we performed some Meta-analysis including eleven independent studies, to further evaluate the outcome(s) when comparing early versus late surgery for IXT. The boundaries between early and late surgery and the surgery methods were not inconsistent, so subgroup analyses were conducted by different boundaries of age at surgery and different surgical approaches. The pooled odds ratios (ORs) and the 95% confidence interval (CI) were estimated according to the random-effects model for high heterogeneity between studies.

RESULTS

Eleven retrospective studies were included in this Meta-analysis. No significant difference between early and late surgery was observed for IXT patients (OR_{First follow-up}=0.88, 95%CI 0.53-1.44, P=0.61; OR_{Final follow-up}=1.48, 95%CI 0.94-2.31, P=0.09). However, sensitivity analysis performed by sequentially omitting individual studies showed that the final follow-up result was not stable. Subgroup analyses revealed that an earlier surgical procedure could lead to a better outcome in the 4-year boundary subgroup as well as the bilateral lateral rectus recession (BLR) subgroup for the final follow-up (OR_4y=2.64, 95%CI 1.57-4.44, P=0.00; OR_BLR=2.25, 95%CI 1.36-3.74, P=0.00).

CONCLUSION

Early surgery for IXT provides a better long term follow-up outcome when patients are younger than 4 years old or choose the BLR surgical method.

Analysis of Postoperative Outcomes in Patients with Intermittent Exotropia According to Preoperative Change of Angle of Deviation

Purpose

The correlation between the existence of the preoperative condition of ≥10 prism diopters (PD) in patients with basic type of intermittent exotropia (IXT) and postoperative outcomes was analyzed.

Methods

The medical records of patients that underwent surgery for IXT were analyzed retrospectively. The analysis was conducted by dividing the patients into a group with change of <10 PD (group 1) and ≥10 PD (group 2) before the time of the surgery. Patients who received at least 6 months of follow-up after surgery were included. The age, sex, angle of deviation and stereoacuity of the patients were studied. Surgical success was defined as exodeviation of <10 PD or esodeviation of <4 PD at the final visit after the surgery. The correlation between clinical factors and surgical success rate was analyzed by using correlative analysis.

Results

A total of 129 patients participated in the study. There were 108 (83.7%) and 21 (16.3%) patients in groups 1 and 2, respectively. There were 89 (82.4%) and 17 (80.1%) patients with surgical successes in groups 1 and 2, respectively (p = 0.18). Moreover, 13 (12.0%) patients in group 1 and three (14.3%) patients in group 2 required reoperation, showing no significant difference (p = 0.12). There was no statistically significant correlation between surgical success and preoperative change of angle of deviation <10 PD (odds ratio, 1.78; p = 0.17).

Conclusions

Among the patients with basic type of IXT subjected to the analysis, 16.3% had a change of ≥10 PD before surgery, and there was no significant correlation between surgical success and preoperative change of angle of deviation.

The Success of Unilateral Surgery for Constant and Intermittent Exotropia and Factors Affecting It in a Large Scandinavian Case Series

PURPOSE

To compare the results of surgery for constant and intermittent exotropia, to determine factors affecting surgical success, and to evaluate the effect of horizontal rectus muscle surgery on distance-near incomitance.

METHODS

In this retrospective study of 291 Scandinavian patients, inclusion criteria were surgery for constant (n = 101) or intermittent (n = 190) exotropia with no vertical deviation, no previous strabismus surgery, and available postoperative follow-up data. Medical records of patients (age: 3 to 85 years) undergoing surgery were reviewed. Surgical success was defined as postoperative esodeviation of less than 5 prism diopters (PD) to exodeviation of 10 PD or less.

RESULTS

Surgical success was 70% in constant exotropia and 80% in intermittent exotropia (P > .05). At follow-up 1.5 years after surgery, a significant drift was found in intermittent exotropia (P < .05). Different surgeons, spherical equivalents, anisometropia, amblyopia, gender, and age had no effect on surgical success (P > .05). The surgical success rate increased with decreasing preoperative angle (P < .05). Resection of the medial rectus muscle had a greater effect on the near deviation, whereas recession of the lateral rectus muscle had a greater effect on the distance deviation (P < .05).

CONCLUSIONS

Surgical success was equally good in constant and intermittent exotropia, but better long-term stability was observed following surgery for constant exotropia. The only factor affecting surgical success was the preoperative deviation, with smaller deviations having a better outcome. A distance-near incomitance may be an important consideration in choosing the magnitude of medial versus lateral rectus muscle surgery. [J Pediatr Ophthalmol Strabismus. 2021;58(1):34-41.].

LACTOSE control scoring helps predict surgical outcomes for childhood intermittent exotropia

OBJECTIVE

To determine whether preoperative Look And Cover, then Ten seconds of Observation Scale for Exotropia (LACTOSE) control scores can predict surgical outcomes in children with intermittent exotropia.

DESIGN

Retrospective interventional case series from a university-based tertiary eye care centre.

PARTICIPANTS

A total of 350 patients with basic-type intermittent exotropia who underwent bilateral lateral rectus recession between 3 and 10 years of age from January 2014 to December 2017.

METHODS

All patients were preoperatively assessed for their degree of control at both distance and near according to LACTOSE scoring system. Demographic, clinical, and oculomotor data before and after surgery were collected and analyzed with regard to the degree of control. Surgical success was defined as an alignment between 10 prism diopters (PD) of exodeviation and 5 PD of esodeviation at both distance and near.

RESULTS

Younger age, lower visual acuity, worse stereoacuity, and larger angle of deviation were associated with higher (i.e., worse) LACTOSE control scores. Of the 350 patients having surgery, 169 (48.3%) were followed for more than 12 months postoperatively. Surgical success was achieved in 132 (78.1%) patients at 12 months after surgery. The only significant predictor of surgical success was preoperative LACTOSE score. There was a significant inverse relationship between LACTOSE scores and surgical success rates for both distance and near scores (p = 0.004 and 0.023, respectively).

CONCLUSIONS

Higher distance and near LACTOSE scores representing worse control of deviation were associated with higher rates of surgical failure in children with intermittent exotropia. This finding indicates that surgical outcome of intermittent exotropia can be predicted by preoperative LACTOSE scores.

Model of a Support Vector Machine to Assess the Functional Cure for Surgery of Intermittent Exotropia

In this paper the optimum timing for the postoperative functional cure of basic intermittent exotropia is explored based on support vector machine (SVM). One hundred and thirty-two patients were recruited in this prospective cross-sectional study with 6 months of follow-up. Examinations included angle of deviation, central and peripheral fusion, controllability, and near and distance stereopsis. Influencing factors of postoperative alignment and stereopsis were analyzed with a chi-squared test and univariate and multivariate logistic regression analyses. At 6 months post-operation, there were 84 successful procedures for the angle of deviation, with 4 overcorrections and 44 undercorrections. The success rate was 63.6%. The angle of deviation on postoperative day 1 was the only significant associated factor. One hundred and thirty patients had normal near stereoacuity, 60 had normal distance stereoacuity according to a Functional Visual Analyzer assessment, and 108 had normal stereoacuity as assessed by the Frisby Davis Distance (FD2) stereotest. The age of onset and preoperative distance stereoacuity with FD2 were the influencing factors of postoperative distance stereopsis restoration. The accuracy of this method of SVM was 82.1%. The angle of deviation for distance on postoperative day 1 was the only significant factor that correlated with alignment at 6 months post-operation, and the model of SVM was useful to determine the optimal time of the postoperative functional cure.

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

BACKGROUND/OBJECTIVES

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

SUBJECTS/METHODS

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

RESULTS

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

CONCLUSIONS

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

Surgical management of intermittent exotropia: do we have an answer for all?

Intermittent exotropia (X(T)) is one of the most common form of strabismus with surgery being the mainstay of treatment. The main goal of surgery is to preserve binocular vision and stereopsis and to prevent its further loss. The decision to operate is mainly based on four aspects: increasing angle of exodeviation, deteriorating control of X(T), decrease in stereopsis for near or distance and quality of life. Bilateral lateral rectus muscle recession and unilateral lateral rectus recession with medial rectus resection, are the two most common surgical procedures performed and have been studied extensively in basic, divergence excess and convergence insufficiency types of X(T). However, there is no consensus over the relative efficacy of the two procedures in terms of postoperative alignment, residual or recurrent exotropia and consecutive esotropia with widely variable results, which can be attributed to poor understanding of the natural course of the disease. Multiple demographic, clinical and anatomic features that may influence the surgical outcomes have been studied to explain this variability. Moreover, most of the evidence regarding surgical outcomes of X(T) is from retrospective studies and the ongoing randomised prospective trials can shed light on long-term efficacy of these procedures. The goal of this review is to give a comprehensive overview of the outcomes of various surgical techniques in the management of different types of X(T), the preoperative and postoperative factors that may affect the surgical outcomes and to discuss the dilemmas faced by the treating surgeons including the effective management of overcorrection and undercorrection.

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.

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.