The Effect of Achieving Immediate Target Angle on Success of Strabismus Surgery in Children

Efficacy of inferior oblique belly transposition combined with inferior oblique recession for asymmetric inferior oblique overaction

OBJECTIVE

To evaluate the efficacy of inferior oblique belly transposition (IOBT) combined with inferior oblique (IO) recession in treating bilateral asymmetric inferior oblique overaction (IOOA).

METHODS

A retrospective review. The data of 14 patients who underwent IOBT on the mild side of IOOA and IO recession on the severe side for bilateral asymmetric IOOA were analyzed retrospectively. The main surgical results including the correction of IOOA, hypertropia, horizontal deviation, V pattern, and fovea-disc angle (FDA) were observed.

RESULTS

The IOBT corrected the preoperative grade (+1.86 ± 0.53) of the mild-side IOOA to a postoperative grade (+0.07 ± 0.27; p < 0.001), and the severe-side IOOA was corrected from a grade of +3.14 ± 0.53 to a postoperative grade of +0.14 ± 0.36 by the IO recession (p < 0.001). The vertical deviation at distance in the primary position was decreased from 8.43 ± 4.05 PD preoperatively to 1.21 ± 1.48 PD postoperatively (p < 0.001). The mean V pattern was 25.00 ± 11.62 PD preoperatively and 3.18 ± 2.18 PD postoperatively (p < 0.001). The mean preoperative FDA on the side where IOBT was performed was -10.47 ± 5.85 degrees, and the postoperative FDA was -7.82 ± 6.42 degrees (p = 0.023). The mean FDA on the side with IO recession was -11.05 ± 5.14 degrees before surgery and -6.09 ± 4.52 degrees after surgery (p = 0.001). The overall success rate was 71.4% (10 of 14).

CONCLUSIONS

IOBT combined with IO recession is effective and safe in eliminating hypertropia, V pattern, and extorsion with bilateral asymmetric IOOA.

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.

A Novel Method Ensuring an Immediate Target Angle After Horizontal Strabismus Surgery in Children

Purpose

Pediatric strabismus surgery has low success rates and high reoperation rates because of difficult alignment measurements and the nature of different strabismus types. Furthermore, adjustable sutures are not easily employed in children on an OPD basis.

Methods

This was a retrospective comparative case study of children less than 12 years old who underwent strabismus surgery and were followed up at least 6 months postoperatively. We proposed a novel method that combines adjustable sutures and corneal light reflexes in regular strabismus surgery to improve surgical results. Efficacy and safety were evaluated and compared with those in a regular fixed-suture group.

Results

In total, 128 children (88: exotropia and 41: esotropia) in the novel method group (Group 1) and 109 (71: exotropia and 38: esotropia) in the regular fixed-suture group (Group 2) were enrolled. The primary outcome was the immediate target angle (for esotropia within 4 PD of orthotropia and exotropia within 8 PD of esotropia within the first week postoperatively); the secondary outcome was success at the 6-month visit (angle of deviation < 10 PD). Consequently, there was a significantly higher proportion of achieving the immediate target range and success rate in both exotropic and esotropic patients in Group 1 than in Group 2. A significantly lower reoperation rate was also demonstrated in Group 1. No complications were noted in either group.

Conclusions: The novel method enabled a higher proportion of subjects to achieve an immediate target range and success rate and a lower chance of reoperation among both esotropic and exotropic patients.

Modified Target Angle as a Predictor of Success in Strabismus Management after Orbital Fracture

Surgery for strabismus secondary to orbital fracture reconstruction surgery has had low success rates and high reoperation rates due to its incomitant nature and complex underlying mechanisms. There has been no consensus as to which of the various methods for improving the surgical results are best. We proposed a modified target angle criteria that combined the regular target angle and a favorable Hess area ratio percentage (HAR%) threshold to evaluate surgical results within the first postoperative week and conducted a retrospective chart review. According to the criteria of the modified target angle at the first postoperative week, a total of 63 patients were divided into two groups: Group 1, patients who fulfilled the criteria (49 patients); and Group 2, those who did not (14 patients). Sex, type of fracture, and the use of porous polyethylene sheets and titanium mesh during reconstruction surgery were significantly different between the groups. Group 1 showed a significantly higher percentage of patients who met the criteria of HAR% > 65% at the first week and >85% (i.e., a successful outcome) at the 6-month visit (p < 0.01). Additionally, Group 1 had a higher HAR% at the first postoperative week (p < 0.01). In conclusion, the patients meeting the criteria of the modified target angle at the first postoperative week had a favorable outcome at the 6-month visit in both ocular alignment and ocular movement.

Extraocular muscle resection, recession length and surgery outcome modelling in strabismus treatment: a pilot study

Background

Many surgical formulas have been developed and proposed based on the experience of surgeons to improve the predictability of strabismus surgery. However, the consent among strabismus surgeons regarding the dose effect of the extraocular muscle (EOM) recession or resection was not achieved yet and the disagreement about the appropriate amount of strabismus surgery still exists.

Objective

Our study aimed to propose an instrument for EOM resection (RsL) and recession length (RcL) estimation before the surgery and second to elaborate an postoperative angle of deviation (PAD) predictive model using simple potential predictors.

Methods and Analysis

The analytical prospective clinical study was conducted from April 2016 to July 2019, on a sample of 216 patients (aged between 2–58) with concomitant strabismus who underwent strabismus surgery in Clinical Republican Hospital ‘Timofei Mosneaga’and Children Hospital ‘Em Cotaga’ from Republic of Moldova. The correlations of patients’ age, strabismus type, amblyopia degree, RsL, RcL, preoperative angle of deviation (PreAD) with PAD were estimated using Pearson’s correlation analysis. Multiple linear regression analysis, multicollinearity analysis and residual analysis were performed.

Results

The EOM RsL was predicted using strabismus type, patient’s age, PreAD and EOM RcL. EOM RcL, in turn, was estimated by the similar covariates set, instead of RcL being RsL. PAD modelling showed the PreAD, EOM RsL and EOM RcL predictive ability for strabismus surgery outcome prediction.

Conclusion

In our study, we propose four mathematical models as potential instruments for EOM RsL, EOM RcL and PAD modelling in esotropia and exotropia surgery.

Comparing Botulinum Toxin Injections with Extraocular Muscle Surgery in Toddlers with Esotropia: A Retrospective Analysis

BACKGROUND

In toddlers with esotropia, early alignment of the visual axes either with extraocular muscle surgery (EOMS) or botulinum toxin injections (BTIs) into both medial rectus muscles may result in improved depth perception. We compared the outcome of BTIs with EOMS in toddlers in order to gain further insight into the advantages and disadvantages of either method.

PATIENTS AND METHODS

In this retrospective study, our encrypted database was searched for toddlers with esotropia aged 35 months or younger at the time of initial treatment with either BTIs or EOMS and who had a follow-up of at least 2 years. We analyzed the angle of deviation, dose effect (DE), and binocularity as well as the number of interventions.

RESULTS

We identified 26 toddlers who received their first treatment for esotropia within the first 35 months of life: 16 with BTIs (9 males, 7 females) and 10 with EOMS (3 males, 7 females). Mean follow-up was considerably longer in the EOMS (87.7 months) than in the BTI group (35.7 months). Age at first intervention was 22.8 months in the BTI and 24.1 months in the EOMS group, and each toddler wore its full cycloplegic refraction. Mean angle at treatment was 41.25 prism diopters (PD) in the BTI compared to 52.9 PD in the EOMS group. The BTI group received an average of 1.68 BTIs, with a mean dosage of 14.5 IU Botox and a mean DE (mDE) of 1.8 PD/IU. In the EOMS group, the average number of surgeries was 1.4, with a mean dosage of 16.85 mm and a mDE of 3.14 PD/mm surgery. Some degree of binocularity could be observed in 9 (56%) of the BTI (5 × Bagolini positive, 2 × 550″, 2 × 220″) and in 4 (40%) of the EOMS group (2 × 3600″, 1 × 550″, 1 × 300″). By the end of the BTI group follow-up, four toddlers electively underwent EOMS rather than a 3rd BTI (followed by a 3rd BTI in 1), which resulted in the appearance of measurable binocularity in all four (1 × Bagolini positive, 1 × 220″, 1 × 200″, 1 × 60″).

CONCLUSIONS

Our results show that BTIs are a viable treatment alternative in early esotropia. Even if EOMS is ultimately required, some binocularity may develop as the visual axes are aligned for some time in the sensitive phase owing to the effects of Botox. Moreover, less surgical dosage is needed than would have otherwise been necessary to treat the original angle of deviation. BTIs are faster, less invasive, and present as an effective alternative when patient compliance is too low to reliably measure the angle of deviation, which is essential for the planning of EOMS.

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.

Outcomes of esotropia surgery in Saudi Arabia: An audit from a single center

Purpose

To monitor the outcomes of surgical correction of esotropia in order to improve preoperative counselling for patients and their families.

Methods

A retrospective review audit of the medical charts at King Fahad Medical City. All patients treated surgically to correct esotropia, from January 2007 to December 2013. All operated cases were included regardless of age and esotropia etiology. The study used a goal-determined metric to assess the outcomes of strabismus surgery > 6 months post-operatively, and on last follow-up. The risk factors for poor surgical outcomes were identified using a Pareto chart.

Results

A total of 99 cases with sufficient documentation to determine the surgical goal were included in the analysis. The goal was to improve eye contact (cosmetic correction) in 77.8% cases, to establish binocularity in 15.2% cases, to resolve diplopia for 4% cases, and to improve anomalous head posture for 3%. The overall outcome was excellent for 70.7% at the first follow-up and for 57.6% at the final visit. Simultaneous vertical muscle surgery and/or superior oblique muscle palsy were risk factors for poor outcome (odds ratio 3.15, 95% CI 1.11–8.99).

Conclusions

Excellent outcome of esotropia surgery in this study is comparable to outcomes reported internationally using the goal determined metrics. Quality improvement processes like the Pareto chart are simple to use and helpful for determining the risk factors associated with poor surgical outcomes after esotropia correction from different etiology.

The difference of surgical outcomes between manifest exotropia and esotropia

PURPOSE

To determine the factors that affect ocular alignment and binocular sensory functions after strabismus surgery and compare surgical outcomes between manifest exotropia (XT) and esotropia (ET).

METHODS

In a retrospective study, 41 XT and 17 ET patients who had undergone strabismus surgery were recruited. Information on type and duration of strabismus, age at onset of deviation and surgery, pre- and postoperative strabismus deviation angles, and binocular sensory functions including stereoacuity and macular fusion capacity was recorded.

RESULTS

In all patients, the ocular alignment and binocular sensory functions improved with time following surgery. Residue strabismus deviation angles (≦ 10 prism diopters) at postoperative 1 month determined the final successful ocular alignment. In patients with final excellent binocular sensory functions, XT group restored macular fusion capacity and stereoacuity at postoperative 1 month, but ET group regained macular fusion capacity at postoperative 1 month and then restored stereoacuity at postoperative 3 months. Though XT patients showed better pre- and postoperative stereoacuity than ET patients, patients with successful ocular alignment had an odd of 4.5 in XT group and 22.5 in ET group to achieve excellent and fair binocular sensory functions.

CONCLUSION

Surgical correction of strabismus could improve ocular alignment and binocular sensory functions in patients with manifest strabismus, regardless of onset age, strabismus duration, or type. Postoperative 1-month status may help to predict the final motor and sensory outcomes. ET patients would benefit more final successful ocular alignment and excellent binocular sensory functions from early surgery and maintaining postoperative small deviation angle than XT patients.

Factors affecting surgical outcome of intermittent exotropia

PURPOSE

The purpose of this study was to investigate the factors affecting surgical outcome in intermittent exotropia.

DESIGNS

This was a retrospective interventional study.

METHODS

Intermittent exotropic patients who had undergone surgical correction with a postoperative follow-up period of 1 month or more were included in the study. Surgical success was defined as an alignment between 10 prism diopters (PD) of exotropia or 5 PD of esotropia at 1 month. After data collection, data were analyzed in SPSS version 23 software. The main outcome measures were the factors affecting surgical outcome.

RESULTS

We included 101 patients, including 52 (51.5%) male and 49 (48.5%) female. Among them, 62 (61.4%) patients achieved surgical success. Undercorrection was the primary reason of surgical failure. Multivariate regression analysis showed that a larger preoperative angle of deviation was associated with unfavorable surgical outcome (P = 0.053, odds ratio [OR] =0.97, 95% confidence interval [CI] = 0.94-1.00), and the presence of postoperative day 1 (POD 1) diplopia correlated significantly with higher surgical success (P = 0.001, OR = 4.54, 95% CI = 1.80-11.43). The presence of POD 1 diplopia was highly associated with POD 1 esotropia (P = 0.005, OR = 7.26, 95% CI = 1.84-28.58).

CONCLUSION

In intermittent exotropia, larger preoperative angle of deviation may predict a lower surgical success rate. Despite a worrisome issue, the presence of diplopia on first POD is associated with immediate postoperative alignment of esotropia and predicts a higher surgical success.

Clinical profiles and surgical outcomes of adult esotropia

OBJECTIVE

The aim of this study was to describe the clinical features and surgical outcomes of teenage and adult patients with esotropia undergoing strabismus surgery with adjustable sutures.

METHODS

Seventy-three patients were included in this retrospective, cohort study. Patients were stratified into group 1 (35 with childhood-onset esotropia [CET]) and group 2 (38 with adult-onset esophoria-tropia [EPT]). Preoperative immediate, 2-week, and 4-6-month postoperative measurements of ocular alignment, as well as fusional testing, were performed. Postoperative success was defined as distant (6 m) and near (33 cm) alignment within 12 prism diopters (PDs) of orthotropia in the primary position at 2 weeks and at 4-6 months with a single surgery.

RESULTS

Patients with CET more frequently had hyperopia and amblyopia and were more likely to present for surgery because of psychosocial strabismus-related problems. Patients with EPT predominantly had myopia and were more likely to experience diplopia and asthenopia. In group 1, the mean preoperative distance deviation improved from 30 PDs to 4 PDs at 2 weeks and to 4 PDs at 4-6 months (p < 0.001). In group 2, mean preoperative distance alignment improved from 22 to 3 PDs at 2 weeks and to 3 PDs at 4-6 months (p < 0.001). The mean objective, single-surgery success rate at 2 weeks was 88% and 97% in groups 1 and 2, respectively. At 4-6 months, postoperative success was 71% in group 1 and 80% in group 2. The majority of patients reported subjective improvement.

CONCLUSIONS

There are distinct preoperative differences between CET and EPT patients. Adjustable, strabismus surgery in this cohort is safe and effective in achieving subjective and objective success.

Early postoperative overcorrection in recurrent exotropia

OBJECTIVE

To investigate the surgical outcome according to the angle of deviation at postoperative day 1 in patients with recurrent exotropia DESIGN: Retrospective case series METHODS: Surgical outcome in patients with recurrent exotropia for at least 1 year was analyzed retrospectively. Patients were divided into 3 subgroups according to the angle of deviation at postoperative day 1: overcorrection group (≥2 prism diopter [PD] of esodeviation), orthotropic group (orthotropia or <5 PD of exodeviation), and undercorrection group (≥5 PD of exodeviation). Success was defined as ≤5 PD of esodeviation or ≤10 PD of exodeviation at the final visit.

RESULTS

One hundred and six patients were included in this study. Age at surgery was 11.8 ± 6.9 years, and preoperative angle of deviation was 22.9 ± 6.3 PD at distant. Patients were followed-up for 24.4 ± 12.8 months. There were 20 (18.9%), 82 (77.4%), and 4 (3.8%) patients in overcorrection, orthotropic, and undercorrection groups at postoperative day 1 (p = 0.001). The surgical success rate at the final visit in the overcorrection group (95%) was higher than that in orthotropic and undercorrection groups (76.8% and 25%, respectively, p = 0.004). In univariate regression analysis, overcorrection at postoperative day 1 was the only reliable factor for long-term success (odds ratio [OR] = 24.101, p = 0.01).

CONCLUSION

Overcorrection at postoperative day 1 is a good surgical predictor of successful outcome in surgery for recurrent exotropia.

Prognostic preoperative factors for successful outcome of surgery in horizontal strabismus

CONTEXT

Surgery for horizontal strabismus reportedly has a success rate of 60%-80%. However, which preoperative factors are predictive of this success is not clear.

AIMS

To identify prognostic factors those are predictive of successful outcome in horizontal strabismus surgery.

SETTINGS AND DESIGN

Observational analytical study using multiple logistic regression (MLR).

SUBJECTS AND METHODS

We assessed the medical records of patients who had undergone first-time horizontal muscle strabismus surgery between 2002 and 2013, where complete follow-up data were available for ≥6 weeks, and also, we collected data prospectively on patients operated between January 2014 and September 2015. Successful outcome was defined as a postoperative angle of deviation within 10 prism diopter of orthophoria at ≥6 weeks postoperatively. Independent variables considered were age at onset, age at surgery, duration, gender, deviation - type and amount, logMAR visual acuity (VA) - mean and of the poorer eye, mean refractive error, amount of anisometropia, and presence of dense amblyopia. Only those with P < 0.2 on univariate analyses (UAs) were included in the MLR, with significance set at P ≤ 0.05.

STATISTICAL ANALYSES

UA (Chi-square for categorical variables and t-tests for continuous variables), followed by logistic regression analysis.

RESULTS

Of 113 patients, on UA, type of deviation (P = 0.01), age at surgery (P = 0.16), absence of dense amblyopia (P = 0.002), and logMAR VA of the poorer eye (P = 0.005) qualified for the inclusion in MLR. On MLR, esotropia (ET) (odds ratio [OR]: 4.46) and absence of dense amblyopia (OR: 5.90) were associated with success.

CONCLUSIONS

With an overall success rate of 83%, ET and absence of dense amblyopia were significantly predictive of surgical success.

Predictors of surgical success in patients with intermittent exotropia

BACKGROUND

In patients with moderate- to large-angle exotropic deviations, surgical correction remains the definitive treatment. The purpose of this study was to identify preoperative factors that correlate with surgical success and to produce a binomial model that predicts success based on preoperative factors.

METHODS

We performed a retrospective review of patients with intermittent exotropia who underwent uniocular recession-resection surgery. Success was defined as ocular deviation ≤10^Δ exotropia and ≤5^Δ esotropia at distance at last follow-up (at least 3 months' postoperatively). Preoperative factors such as age at surgery, sex, visual acuity, spherical equivalent, prism fusion range, stereopsis, and ocular deviation were analyzed for correlation with success using binomial logistic regression.

RESULTS

A total of 82 patients were identified (average age, 33 years; range, 3.7-81.6 years). Average prismatic deviation was 35^Δ at near and 34^Δ at distance. Average stereopsis was 167″. The average success rate was 58.5%. Univariate binomial regression revealed that patients with smaller angle of deviation at near (OR = 0.96, P = 0.013) or distance (OR = 0.96, P = 0.005), larger myopic refractive errors in terms of mean spherical equivalent (OR = 0.71, P = 0.022) and spherical equivalent in the more myopic eye (OR = 0.75, P = 0.029) contributed to success. A multivariate regression model was able to predict success with an accuracy of 72% (sensitivity, 81%; specificity, 58%; negative predictive value, 67%; positive predictive value, 74%).

CONCLUSIONS

A smaller preoperative angle of deviation and larger myopic refractive error correlated with success in uniocular intermittent exotropia surgery in our cohort. Larger deviations and more hyperopia correlated with lower success rates.