Analysis of risk factors for consecutive exotropia and review of the literature

Characteristics and risk factors for spontaneous and postoperative consecutive exotropia in children with esotropia

Background

To investigate the risk factors for the development of consecutive exotropia (CXT) by comparing patients with spontaneous or postoperative CXT during follow-up with another group of patients who had no deviation or less than 10 prism dioptre (PD) esotropia.

Methods

In this retrospective cohort study, 6 patients with spontaneous CXT (group A), 13 patients with postoperative CXT (group B), and 39 patients with no exotropia (group C) were enrolled. Probable risk factors for CXT were evaluated among the groups. Kruskal-Wallis H test was used to determine if any significant differences were present among the groups. Fisher's exact test or Mann-Whitney U test was used for univariate analyses to compare differences between case groups or between case and control groups. The Bonferroni method was used to conduct multiple comparisons.

Results

The follow-up period of spontaneous CXT patients was significantly longer than that of postoperative CXT and nonconsecutive exotropia patients (p = 0.035 and p < 0.001, respectively). The interval between alignment and CXT onset in spontaneous CXT patients was slightly longer than that in postoperative CXT patients, but not significantly difference (6.50 vs. 5.00 years, p = 0.072). Vertical deviation was associated with a high risk of postoperative CXT (p = 0.001). Most [38 (97.44%)] nonconsecutive exotropia patients had fusion; conversely, the absence of fusion function (p < 0.001) as well as stereoacuity (p = 0.029) were associated with a high risk of CXT.

Conclusion

Vertical deviation and poor binocular function are strongly associated with a high risk of CXT. Children with spontaneous CXT are highly recommended to be followed-up long-term, while they maintain long-term ocular alignment before developing consecutive exotropia from comitant esotropia (CE).

Advancement of the muscle insertion toward the limbus as an alternative or adjunct to resection

PURPOSE

To describe the surgical outcomes of patients that underwent strabismus surgery involving advancement of the muscular insertion line toward the limbus.

METHODS

The medical records of patients who underwent rectus muscle advancement surgery between January 2009 and June 2019 and had at least 1 year of follow-up were reviewed retrospectively. Patients were classified into one of four types of deviation: (1) convergence insufficiency, without distance deviation; (2) small-angle distance esotropia, with diplopia; (3) residual strabismus after previous surgery; and (4) large-angle exotropia. The first group underwent 2 mm advancement of the medial rectus insertion bilaterally; the second, 2-3 mm advancement of the lateral rectus muscle bilaterally; the third, 2-3 mm advancement of the lateral or medial rectus muscle, with or without simultaneous resection; and the fourth, 3 mm advancement of the medial rectus with simultaneous resection, with or after maximum recession of the lateral rectus, bilaterally or unilaterally.

RESULTS

A total of 25 patients were included (mean age, 28.76 ± 22.75 years): 4 with convergence insufficiency, 3 with small-angle distance esotropia and diplopia, 16 with residual strabismus, and 2 with large-angle exotropia. Mean postoperative follow-up was 4.76 ± 2.03 years. Surgery was successful in all patients at 1 year (residual deviation ≤10^Δ), and all but 1 at 5 years; 1 patient required reoperation.

CONCLUSIONS

Advancement of the muscle insertion proved successful as an alternative or adjunctive procedure to other forms of muscle tightening in the subtypes of patients evaluated in this study.

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.

Evaluation of the insertion distance of the medial rectus in consecutive exotropia by means of intraoperative measure and optical coherence tomography

PURPOSE

To assess the agreement between the measurements of the distance from the medial rectus muscles insertion to the limbus measured by intra-operative spectral-domain optical coherence tomography (SD-OCT) in consecutive exotropia (cXT).

METHODS

An analysis was performed on total of 14 medial rectus (MR) muscles of 14 patients who underwent surgery for the treatment of cXT. The limbus-insertion distance of the MR muscles was measured using preoperative SD-OCT and intraoperatively using a calliper. The intraclass correlation coefficient (ICC) and Bland Altman plots were calculated to determine the agreement between the two methods, as well as the correlation.

RESULTS

Mean age was 36.3 ± 16.0 years (range 13-60), with 60% being women. Mean preoperative deviation was 38.7 ± 16.9 prismatic dioptres (PD) (range 16-65), being +1.3 ± 6.3 PD (range -12 to +10 PD) after surgery. Intraoperatively the MR insertion was found at 8.7 ± 2.1 mm (range 5.5-12.0) and by OCT at 7.7 ± 1.2 mm (range 5.3-10.0). The ICC showed a moderate to good agreement (0.659; 95% confidence interval: 0.157-0.885; p < 0.001), with a correlation of R = 0.792 (p = 0.011). A better agreement was observed in those MR that were less retro-inserted.

CONCLUSIONS

SD-OCT is able to measure the insertion to the limbus distance of the medial rectus muscles that have been previously operated on, showing moderate to good agreement with intraoperative measurements. However, the agreement was poor in muscles with a large retro-insertion.

Surgical treatment of consecutive exotropia: Comparison of different surgical methods applied to one eye in one session

PURPOSE

To compare the different surgical methods performed on a single eye in a single session and the factors that affect the success of patients having consecutive exotropia (XT) developed after esotropia surgery.

METHODS

The medical data of the patients who underwent surgery for consecutive XT were reviewed retrospectively. Patients with followed of 6 months or more were divided into four groups; patients with medial rectus (MR) advancement (Group 1 = 10), MR advancement and MR resection (Group 2 = 12), MR advancement and lateral rectus (LR) recession (Group 3 = 13), MR advancement, MR resection, and LR recession (Group 4 = 14). Success results and possible risk factors were investigated.

RESULTS

Forty-nine patients with consecutive XT (21 female, 28 male) were enrolled in the study. The mean age of overall patients was 22.97 years at surgery for consecutive XT. The groups did not display significant differences in terms of surgery ages, gender, refraction values, visual acuity, amblyopia, inferior oblique overaction, limitation of adduction, surgical success rates, and follow-up time (p > 0.05). Patients of Group 4 had larger preoperative and postoperative deviation, while Group 1 had smaller (p < 0.05). The surgical success rates of Groups 1, 2, 3, 4 were 90%, 75%, 76.9%, and 50%, respectively (p = 0.192). Statistically, no factor was found to be effective in surgical success rates (p > 0.05).

CONCLUSION

Surgical treatment of consecutive XT is successful in most of the patients with numerous surgical options performed on a single eye in a single session. Patients, particularly with a high amount of deviation should be warned about the possibility of additional surgery.

Augmented Lateral Rectus Recession for Consecutive Exotropia

Purpose: To evaluate the efficacy of augmented bilateral lateral rectus recession in the treatment of consecutive exotropia.Methods: We retrospectively reviewed records of nine patients who underwent augmented bilateral lateral rectus recession for consecutive exotropia with minimal adduction deficits. Our normal surgical dosing tables for bilateral lateral rectus recession were augmented by adding 1.5-2 mm. All patients had been measured preoperatively using prism and alternate cover testing (PACT), except for one patient in whom Krimsky measurements were performed because of amblyopia. Surgery was deemed successful if postoperative alignment fell within a potential monofixation range of ±10 prism diopters (PD) by PACT at the final postoperative examination.Results: Eight out of nine patients (89%) had a successful outcome. One patient was surgically undercorrected. Despite successful realignment to a state of monofixation syndrome in most patients, there was no significant restoration of stereopsis following strabismus surgery.Conclusions: Surgical augmentation of bilateral lateral rectus recession standard dosing by 1.5-2 mm is efficacious for restoring binocular alignment for both distance and near fixation. This surgical approach may be preferable to bimedial advancements in patients with minimal preoperative adduction deficits who show no significant increase in exotropia during near fixation.

Management of consecutive exotropia

Purpose:

To determine the clinical characteristics and surgical outcomes of medial rectus (MR) advancement with or without lateral rectus (LR) recession in patients with consecutive exotropia.

Methods:

This interventional case series was performed on patients with consecutive exotropia of more than 15 prism diopters (PD) at least 6 months after the esotropia surgery. All patients were operated using either unilateral or bilateral MR muscle advancement with or without simultaneous LR recession. Ocular deviation at far and near distances, adduction limitation, and exoshift were investigated at the follow-ups of 1 week, as well as 1, 3, and 6 months after the surgery. Operation was considered successful when the postoperative far deviation was <10 PD.

Results:

Thirty patients were evaluated. The mean amount of MR advancement was 5.69 ± 1.33 mm with the mean dose response of 4.7 ± 3.3 and 4.55 ± 4.01 PD at 3 and 6-month follow-ups, respectively. Success rate was reduced from 93% at week 1 to 73% at month 6 due to postoperative exodrift, especially during the first 3 months. Preoperative exotropia was the only contributing factor in our study.

Conclusions:

MR advancement was an effective surgical method for consecutive exotropia correction, especially in cases with MR underaction. Bilateral MR advancement and/or LR recession are suggested in cases with higher preoperative exodeviation. The presence of postoperative exodrift indicates longer follow-ups for patients.

Evaluation of the insertion distance of the medial rectus in consecutive exotropia by means of intraoperative measure and optical coherence tomography

PURPOSE

To assess the agreement between the intraoperative measurements of the distance from the medial rectus muscles insertion to the limbus and preoperative spectral-domain optical coherence tomography (SD-OCT) in consecutive exotropia (cXT).

METHODS

An analysis was performed on total of 14 medial rectus (MR) muscles of 14 patients who underwent surgery for the treatment of cXT. The limbus-insertion distance of the MR muscles was measured using preoperative SD-OCT and intraoperatively using a calliper. The intraclass correlation coefficient (ICC) and Bland Altman plots were calculated to determine the agreement between the two methods, as well as the correlation.

RESULTS

Mean age was 36.3±16.0 years (range 13-60), with 60% being women. Mean preoperative deviation was 38.7±16.9 prismatic dioptres (PD) (range 16 to 65), being +1.3±6.3 PD (range -12 to +10 PD) after surgery. Intraoperatively the MR insertion was found at 8.7±2.1mm (range 5.5 - 12.0) and by OCT at 7.7±1.2mm (range 5.3 - 10.0). The ICC showed a moderate to good agreement (0.659; 95% confidence interval: 0.157-0.885; P<.001), with a correlation of R=0.792 (P=.011). A better agreement was observed in those MR that were less retro-inserted.

CONCLUSIONS

SD-OCT is able to measure the insertion to the limbus distance of the medial rectus muscles that have been previously operated on, showing moderate to good agreement with intraoperative measurements. However, the agreement was poor in muscles with a large retro-insertion.

Consecutive strabismus after infantile nystagmus syndrome surgery and potential risk factors

PURPOSE

The aim of this study is to evaluate the incidence of consecutive strabismus after infantile nystagmus surgery and its potential risk factors.

METHODS

A retrospective study including 89 patients was conducted. Patients presented infantile nystagmus (idiopathic or ocular disease-associated nystagmus) without previous or coincidental strabismus. Sex, age at surgery, amblyopia, botulinum toxin (BT) injection before surgery, spherical equivalent, anisometropia, surgery procedure (Anderson's or retroequatorial recessions of four horizontal recti), and follow-up were analyzed. Kaplan-Meier and univariate Cox regression were performed.

RESULTS

The median age at surgery was 5 years. The median follow-up was 36 months. The incidence of consecutive strabismus was 11.2%. There were eight patients with exotropia and two patients with esotropia. Consecutive strabismus was associated with severe bilateral amblyopia (p = 0.036), previous treatment with BT injection (p = 0.025), and large recessions of the four horizontal muscles (p = 0.001). The hazard ratio for patients with severe bilateral amblyopia was 5.4 (95% CI 1.1-25.8), and for patients previously treated with BT was 6.1 (1.3-29.3). The survival rate was 95.4% at 6 months and 88.5% at 3 years.

CONCLUSION

Severe bilateral amblyopia, previous BT treatment, and type of surgery seem to be associated with consecutive strabismus after infantile nystagmus surgery. Most cases appear within the first months after surgery.

Clinical and surgical risk factors for consecutive exotropia

Introduction:

Consecutive exotropia is one of the complications of esotropia surgery. Its prevalence is estimated at 4%–27%. The aim of this study was to identify the risk factors for consecutive exotropia in the aftermath of surgical treatment of esotropia.

Methods:

Seventy-four patients examined in our strabismus consultation for a consecutive exotropia from January 2010 to June 2016 were retrospectively included. The age of onset of esotropia, the presence of amblyopia, the age of esotropia surgery and chosen procedure, the refractive errors, the anomalies of ocular motility, the age of onset of the consecutive exotropia and its angle of deviation were reported. Statistical analyses were performed with Student’s test and Fisher’s exact test.

Results:

Esotropia occurred in 65% of cases before the age of 1 year, was associated with amblyopia in 51%, hyperopia in 55% or anisometropia in 31%. Surgery was performed before the age of 6 years for 55% of the patients and involved for 52% the both medial recti. The angle of deviation of consecutive exotropia was ≤20 prism dioptres (PD) in 39%, 21-40 PD in 39% and ≥ 40 PD in 22%, related to amblyopia (p = 0.028), and to high hypermetropia (p = 0.05).

Discussion:

Amblyopia and hyperopia were the most important risk factors of consecutive exotropia in our series. Early onset esotropia, stereopsis abnormalities, anisometropia, oblique dysfunction, convergence insufficiency appeared but did not reach statistical significance.

Conclusion:

Amblyopia is a major risk factor that should be taken into consideration during surgery of an esotropia.

Time and Factors Affecting the Direction of Re-drift in Essential Infantile Esotropia

PURPOSE

To investigate the development pattern and related factors of postoperative re-drift in infantile esotropia.

METHODS

A total of 112 patients with infantile esotropia who underwent surgery before 3 years of age were included. Surgical outcomes were divided into (1) consecutive exotropia: more than 8 prism diopters (PD) of exodeviation; (2) recurrent esotropia: more than 8 PD of esodeviation; and (3) monofixation syndrome: maintenance of deviations within 8 PD. The occurrence rate, time of onset, and associated factors of the re-drift were evaluated.

RESULTS

At a mean follow-up of 9.5 years, consecutive exotropia developed in 37 patients (33.0%) and recurrent esotropia in 43 patients (38.4%). Whereas 76.7% of total recurrent esotropia cases were identified within postoperative 1 year, consecutive exotropia occurred constantly over 10 years postoperatively. The mean time to consecutive exotropia development from surgery was 78.6 months, greater than that of recurrent esotropia development (8.9 months) (P < 0.001). In multinomial logistic regression using monofixation syndrome as the reference category, fixation preference before surgery (odds ratio [OR]: 6.64, 95% confidence interval [CI]: 2.07 to 21.32) and the rate of myopic progression (OR: 15.07 per -1.00 D/year, 95% CI: 1.23 to 184.86) were associated with consecutive exotropia, whereas increase in the angle of esodeviation on postoperative day 1 (OR: 1.15, 95% CI: 1.04 to 1.26) was correlated with recurrent esotropia.

CONCLUSIONS

This study demonstrates a difference between the development pattern of exotropic and esotropic drift after infantile esotropia surgery. Detailed preoperative assessment and close postoperative observation of deviations and refractive status will help to determine surgical outcomes of infantile esotropia. [J Pediatr Ophthalmol Strabismus. 2018;55(2):128-134.].

Factors associated with atypical postoperative drift following surgery for consecutive exotropia

PURPOSE

To evaluate the associations of clinical and surgical factors with atypical postoperative drift following surgery for consecutive exotropia.

METHODS

A total of 66 patients with consecutive exotropia (≥10^Δ at distance), after historical surgery for esotropia were retrospectively identified at a tertiary medical center. All patients underwent unilateral lateral rectus recession (on adjustable suture) with medial rectus advancement and/or resection. Immediate postoperative target angle was 4^Δ-10^Δ of esotropia at distance, anticipating mild postoperative exodrift. Actual postoperative drift was calculated as change in distance deviation from immediately postadjustment to 6 weeks. Typical drift was defined as 0^Δ-9^Δ of exodrift. Excessive exodrift was defined as ≥10^Δ. Esodrift was defined as 1^Δ or more. Univariate and multiple logistic regression analyses were performed to evaluate for associations with a wide range of clinical and surgical factors.

RESULTS

Overall there was a median exodrift (4^Δ, quartiles 0^Δ-10^Δ). Of the 66 patients, 18 (27%) showed excessive exodrift; 15 (23%), esodrift. In multiple logistic analyses, larger preoperative distance exodeviation was associated with excessive exodrift (P = 0.01), and non-normal medial rectus attachment status (abnormal [stretched scar, pseudo-tendon], attached to pulley, or behind pulley) was associated with esodrift (P = 0.02).

CONCLUSIONS

Approximately half of patients show atypical drift following unilateral surgery for consecutive exotropia, with larger preoperative distance exodeviation associated with exodrift and non-normal medial rectus muscle status with esodrift. Knowing these associations may help when counseling patients regarding surgical outcomes.

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.

Risk factors analysis of consecutive exotropia: Oblique muscle overaction may play an important role

To evaluate clinical factors associated with the onset of consecutive exotropia (XT) following esotropia surgery.By a retrospective nested case-control design, we reviewed the medical records of 193 patients who had undergone initial esotropia surgery between 2008 and 2015, and had follow-up longer than 6 months. The probable risk factors were evaluated between groups 1 (consecutive XT) and 2 (non-consecutive exotropia). Pearson chi-square test and Mann-Whitney U test were used for univariate analysis, and conditional logistic regression model was applied for exploring the potential risk factors of consecutive XT.Consecutive exotropia occurred in 23 (11.9%) of 193 patients. Patients who had undergone large bilateral medial rectus recession (BMR) (P = 0.017) had a high risk of developing consecutive XT. Oblique dysfunction (P = 0.001), adduction limitation (P = 0.000) were associated with a high risk of consecutive XT, which was confirmed in the conditional logistic regression analysis. In addition, large amount of BMR (6 mm or more) was associated with higher incidence of adduction limitation (P = 0.045). The surgical methods and preoperative factors did not appear to influence the risk of developing consecutive XT (P > 0.05).The amount of surgery could be optimized to reduce the risk of consecutive XT. The presence of oblique overaction and postoperative adduction limitation may be associated with a high risk of consecutive XT, which may require close supervision, and/or even earlier operation intervention.

Clinical risk factors for the development of consecutive exotropia: a comparative clinical study

AIM

To compare a group of patients with consecutive exotropia with patients who had ≤10 prism diopters (PD) esotropia or no deviation postoperatively in terms of probable clinical risk factors for the development of consecutive exotropia.

METHODS

The study recruited fourteen patients who developed consecutive exodeviation during follow-up period after the correction of esotropia who were categorized as group 1 and thirty-one patients who had still ≤10 PD esotropia or no deviation at the final visit that were considered as group 2. Clinical risk factors leading the development of consecutive deviation were analyzed as the main outcome measures.

RESULTS

The mean age of patients was 4.57±3.11y in group 1 and 5.10±3.52y in group 2 (P=0.634). There was no significant difference of preoperative near and distant deviations among two groups (P=0.835, 0.928 respectively). The mean amount of medial rectus recession and lateral rectus resection was similar in both groups (P=0.412, 0.648 respectively). Convergence insufficiency and neurological diseases were more frequent in group 1 (P=0.007, 0.045). Accompanying neurological disease was found to be as a significant factor increasing the risk of the development of consecutive exotropia significantly [odds ratios (OR): 5.75 (1.04-31.93)].

CONCLUSION

Accompanying neurological disease appears to be a significant clinical risk factor for the development of consecutive exodeviation during postoperative follow-up after the correction of esotropia. However, larger studies are needed in order to interpret the results to the clinical practice and to ascertain other concurrent risk factors.

Tendon elongation with bovine pericardium (Tutopatch®) when conventional strabismus surgery is not possible

PURPOSE

Sometimes, a conventional recess-resect surgery may not be sufficient to obtain satisfactory ocular alignment. Patients who have previously undergone surgery and/or have a large difference in visual acuity between both eyes and do not wish to undergo surgery on the sound eye provide a surgical challenge. In these cases, tendon elongation with bovine pericardium may be an option.

METHODS

We retrospectively reviewed the charts of 38 patients who underwent strabismus surgery with tendon elongation. Before surgery, 31 had exotropia (angle -21.8 ± 5.7 degrees) and 7 esotropia (angle +19.1 ± 5.4 degrees). Reasons for tendon elongation included the following: 15 patients refused surgery on their sound eye; in 15 patients, conventional recess-resect was not possible; and in 7 patients, the elongation best fitted the motility pattern. In one patient, tendon elongation was preferred over conventional recession because of a thin sclera. Follow-up was 0.5 to 4 years.

RESULTS

At last follow-up visit, in patients with previous exotropia, the angle was -3.3 ± 5.9 degrees; in patients with previous esotropia, +0.2 ± 0.5 degrees. Most had some duction limitation in the direction of the elongated muscle. All patients but one were satisfied with the result. In the patients with previous exotropia, there was a small but nonsignificant regression to recurrence of the exodeviation (on average 0.5 degree per year).

CONCLUSIONS

Tendon elongation is a valuable addition to our strabismus surgery repertoire. However, because of duction limitations after surgery, it should be reserved for those cases in which conventional surgery is not an option.