Unilateral recession-resection in children with exotropia of the convergence insufficiency type

The role of diagnostic monocular occlusion test in basic type intermittent exotropia

To assess the response to monocular occlusion test in basic type intermittent exotropia (IXT) and to evaluate the surgical outcomes of titrated surgery based on the test's result. Medical records were retrospectively reviewed for patients who underwent bilateral lateral rectus recession for basic type IXT. Patients were categorized into two groups: those who underwent a preoperative diagnostic monocular occlusion test (occlusion group) and those who did not (no occlusion group). In the occlusion group, patients exhibiting a change in deviation angle of ≥ 5 prism diopters (PD), either at distance or near fixation following occlusion therapy, were classified as responders, and augmented surgery was performed for patients with an increased deviation. A total of 215 patients were included in this study, with 79 patients (36.7%) in the no occlusion group and 136 patients (63.3%) in the occlusion group. In the occlusion group, while the mean distance deviation did not significantly change, the mean near deviation significantly increased from 27.2 ± 7.7 PD to 32.5 ± 8.6 PD after diagnostic monocular occlusion (p < 0.001). 58% (58%) of patients showed an increase in near deviation angle of 5 PD or more. Patients with good fusional control at near fixation were more likely to show a change in their deviation after the occlusion (odds ratio = 1.722, p = 0.028). The success rate of the strabismus surgery was significantly higher, and recurrence rate was significantly lower in the occlusion group compared to the no occlusion group (p = 0.025 and p = 0.030), while overcorrection rate was not significantly different between the two groups (p = 1.000). Over half of the patients with basic type IXT demonstrated a significant increase in near deviation angle after diagnostic monocular occlusion. Diagnostic monocular occlusion may be useful for revealing the maximum deviation angle at near fixation and may help determine the optimal surgical dosage in basic type IXT.

Slanted and Standard Lateral Rectus Recession Procedures for Convergence Insufficiency-Type Intermittent Exotropia in Children: A Retrospective Cohort Study

Purpose

To evaluate the efficacy and safety of slanted bilateral lateral rectus recession (BLR-rec) for treating convergence insufficiency-type intermittent exotropia (CI-IXT) in children.

Methods

In this retrospective cohort study, 26 patients aged <16 years with CI-IXT who underwent BLR-rec between August 2016 and July 2021 with six months of follow-up data post-surgery were classified into slanted BLR-rec group (n = 14) and standard BLR-rec group (n = 12; equal-length recession of the upper and lower horns of the LR muscle). Surgical outcomes were compared between the groups.

Results

In the slanted and standard groups, the preoperative distance exodeviation was 27.9 ± 5.5 and 30.8 ± 10.0 prism diopter (PD) (p = 0.63), near exodeviation was 41.1 ± 5.6 and 42.9 ± 9.2 PD (p = 0.75), and difference between near and distance deviation (N-D deviation difference) was 13.2 ± 3.2 and 12.1 ± 3.3 PD (p = 0.30), respectively. The ratio of postoperative and preoperative N-D deviation difference was compared between the slanted BLR and standard BLR groups at six months postoperatively. The results revealed that the ratio for slanted-BLR was 0.44 ± 0.19, and for standard-BLR was 0.84 ± 0.24. In the standard group, stereoacuity remained unchanged post-surgery compared to that pre-surgery, while the slanted group showed significant improvement (p < 0.05, Wilcoxon signed-rank test).

Conclusion

Compared with the standard BLR-rec procedure, the slanted BLR-rec procedure reduced N-D deviation differences in CI-IXT, positively impacting gross stereopsis.

Long-term surgical outcome and impact on daily life activities of strabismus surgery in thyroid-associated ophthalmopathy with and without previous orbital decompression

BACKGROUNDS

To report the long-term surgical outcomes and the impact on daily life activities of strabismus surgery in patients with Thyroid Associated Orbitopathy (TAO) with and without previous orbital decompression.

METHODS

Patients who underwent strabismus surgery for TAO were retrospectively reviewed. The primary outcome was to evaluate the influence of orbital decompression on the outcomes of TAO related strabismus surgery. Surgical success was defined by the resolution of diplopia and a post-operative deviation < 10 prism diopters (PD). The secondary outcomes were the clinical features, surgical approaches, and impact on daily life activities.

RESULTS

A total of 45 patients were included in the study. The decompression surgery group (DS) included 21 patients (46.7%), whereas the non-decompression surgery group (NDS) patients were 24 (53.3%). The mean follow-up time from the last strabismus surgery was 2,8 years (range 8-200 months). Successful surgical outcome was achieved in 57,1% of patients in the DS, and 75% of patients in the NDS (p = 0,226). DS patients required almost twice the number of surgical interventions for strabismus compared to the NDS (1,95 vs. 1,16 respectively, p = 0,006), a higher number of extraocular muscles recessed in the first surgery (2,67 vs. 1,08 respectively, p < 0.001), and a lower rate of unidirectional surgery compared to NDS (23% vs. 95%, p < 0,001). At the pre-operative assessment, 71.4% of DS patients had eso-hypotropia, while no patients had this type of strabismus in the NDS group (p < 0.001). On the other hand, the hypotropia rate was 79.2% in NDS patients and only 4.8% in DS patients (p < 0.001). Moreover, 21,8% of NDS patients used prism lenses in daily life activities, compared to 42.9% of patients that used prism lenses to reduce the impairment in their daily life activities (p = 0.016).

CONCLUSIONS

The results of our study showed that DS patients required almost twice the number of strabismus surgical procedures, a higher number of extraocular muscles recessed in the first surgery, and an increased need for prism lenses to correct the residual deviation compared to the NDS, but with similar long-term surgical outcomes.

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.

Treatment of convergence insufficiency type intermittent exotropia with bupivacaine injection to the medial rectus combined with lateral rectus recession

PURPOSE

To evaluate the outcomes of combined bupivacaine HCL (BPX) injection in the medial rectus (MR) muscle with recession of the lateral rectus muscle in the treatment of convergence insufficiency-type intermittent exotropia (CI-IXT).

METHODS

The medical records of patients who underwent combined injection-recession treatment from January 2019 to January 2020 for CI-IXT were reviewed retrospectively along with a group of age-matched controls with IXT without CI who underwent only unilateral LR recession during the same period. The following data were extracted from the record: age at surgery, average follow-up period, angle of deviation at distance and near and the difference between them before and after surgical procedure, correction of near and distance deviations, and recession dosage. Successful outcome was defined as a distance deviation in primary gaze between ≤10^Δ of exophoria/tropia and ≤5^Δ of esophoria/tropia.

RESULTS

A total of 10 patients and 20 controls were included. Average follow-up was 13.9 ± 3.67 months in the BPX group and 15.9 ± 3.61 months in the control group (P = 0.17). Postoperative distance deviation measured 8.30^Δ ± 5.88^Δ in the BPX group and 14.67^Δ ± 9.83^Δ in the control group (P = 0.80). Distance-near differences were significantly reduced in the CI-IXT group receiving BPX, by a mean of 6.60^Δ, from a preoperative mean of 10.50^Δ ± 3.65^Δ to 3.90^Δ ± 3.26^Δ (P < 0.01).

CONCLUSIONS

BPX injection combined with unilateral lateral rectus recession yields outcomes comparable to bilateral lateral rectus recession for distance deviations, and results in reduction of the distance-near difference in the angle of exotropia.

Surgical outcomes of unilateral lateral rectus recession versus recess-resect in children with convergence insufficiency type intermittent exotropia

To determine the efficacy of unilateral lateral rectus recession (ULR) for convergence insufficiency-type intermittent exotropia (CI-type IXT), we compared surgical outcomes following ULR and recess‒resect (RR) procedures for CI-type IXT. In this retrospective study, medical records of 57 children who underwent ULR (n = 30) or RR (n = 27) for CI-type IXT of less than 25 PD at distance with a postoperative follow-up of 6 months or more were reviewed. Surgical success was defined as an alignment between 10 PD exodeviation and 5 PD esodeviation at distance and near fixation. The postoperative exodeviation showed no significant difference between the two groups at the last follow-up. A significant reduction in the mean near-distance difference was achieved postoperatively in both groups: from 5.4 PD preoperatively to 2.5 at last follow-up after ULR, and from 8.2 to 2.4 after RR (both p = 0.001). However, this difference between ULR and RR was not statistically significant (p > 0.05). The success rate at the last follow-up was 63.3% for ULR and 70.4% for RR (p = 0.574). ULR was found to be an effective treatment for CI-type IXT, with similar surgical outcomes to RR.

Slanted recession on bilateral lateral rectus for the treatment of intermittent Exotropia with convergence insufficiency

Purpose

To evaluate the efficacy and safety of slanted bilateral lateral rectus recession (S-BLRc) for the treatment of convergence insufficiency-type intermittent exotropia (CI-IXT) in children and to probe the relationship of the slanted amount and surgical outcomes.

Methods

Retrospective study. Fifty-eight patients with CI-IXT, aged 4 to 10 years old, underwent S-BLRc procedures. According to the different slanted amount between the upper and lower poles of lateral rectus, all the patients were grouped: Group A (slanting 1 mm, n = 22), Group B (slanting 1.5 mm, n = 18) and Group C (slanting 2 mm, n = 18). The successful surgical outcome was defined as deviation in the primary position ranging from exotropia< 8^△ to esotropia< 5^△ both at near and at distant as well as the near-distance difference (NDD) < 5^△. We analyzed and compared the preoperative and postoperative data including deviations both at near and at distance, NDD, objective torsion, horizontal deviation at up and down gaze, lateral incomitance, binocular vision and surgical success rate among three groups.

Results

The average deviations were significantly decreased from − 37.1^△ ± 4.2^△ (−,exotropia) to − 1.4^△ ± 4.6^△ at near (P < 0.05) and from − 25.8^△ ± 3.7^△ to − 0.1 ± 4.1^△ at distance (P < 0.05). The postoperative NDD on average was significantly reduced from 10.0^△ to 1.8^△ in Group A (P < 0.05), from 11.2^△ to 0.8^△ in Group B (P < 0.05) and from 13.3^△ to 0.9^△ in Group C (P < 0.05). There was a significant difference in the mean corrections of NDD among the three groups (8.2^△ in group A, 10.3^△ in group B and 12.4^△ in group C respectively, P < 0,05). All the patients attained various improvement of stereopsis after surgery. None had torsional diplopia, A-V pattern and lateral incomitance after strabismic surgery. Totally, the surgical success rate was 89.7% in our series at the 6- to 8-month follow-up.

Conclusions

Slanted bilateral lateral rectus recession is an effective and safe procedure for the treatment of CI-IXT in children. S-BLRc can successfully collapse exotropia both at distance and at near, decrease NDD and benefit to gain binocular vision. The correction of NDD was associated with the slanted amount.

Slanted bilateral lateral rectus recession for convergence insufficiency-type intermittent exotropia: a retrospective study

Background

The present study sought to investigate the efficiency and safety of slanted bilateral lateral rectus recession for the treatment of convergence insufficiency-type intermittent exotropia.

Methods

This retrospective study included 34 patients who underwent slanted bilateral lateral rectus recession for convergence insufficiency-type intermittent exotropia in Shandong Provincial Hospital affiliated to Shandong First Medical University between September 2013 and October 2015 with a minimum follow-up of 6 months. A successful surgical alignment was defined as + 5 (positive for esotropia) to − 10 (negative for exotropia) prism diopters (PD) of orthotropia in the primary position while viewing distant or near targets and a near-distance deviation difference ≤ 8PD.

Results

The mean age of the patients at surgery was 7.09 ± 3.80 years (range, 3 to 18 years). The mean distance deviations were − 26.09 ± 6.5 PD (range, − 15 to − 35 PD) and the mean near deviations, − 37.21 ± 6.3 PD (range, − 25 to − 45 PD) preoperatively. The mean recession amount of upper pole of the lateral rectus was 5.97 mm (range, 4.0 to 7.5 mm) and that of lower pole of the lateral rectus, 7.49 mm (range, 6.0 to 8.5 mm). At a mean follow-up of 15.0 months (range, 6 to 37 months), the surgical success rate was 70.6% (24/34), the under-correction rate was 17.6% (6/34), and the overcorrection rate was 11.8% (4/34). The mean near-distance deviation difference was significantly reduced from 11.12 ± 2.06 PD (range, 10 to 15 PD) preoperatively to 2.47 ± 3.04 PD (range, 0 to 10 PD) postoperatively (P < 0.001). Each millimeter of difference between the upper and lower poles of the lateral rectus recession was associated with an improvement of 5.65 PD in the near-distance deviation difference. At the final follow up, a near-distance deviation difference of ≤8PD was found in 32 (94.1%) patients. None of the patients developed A-V pattern, torsional diplopia, or restricted abduction of the eyes.

Conclusions

Slanted bilateral lateral rectus recession may successfully reduce the distance and near exodeviations and the near-distance deviation difference, thus was proved to be an effective and safe procedure for the treatment of convergence insufficiency-type intermittent exotropia.

Comparison of surgical outcomes of slanted procedure for exotropia with convergence insufficiency according to their response to preoperative monocular occlusion

The aim of this prospective study was to compare surgical outcomes of slanted bilateral lateral rectus (LR) recession for intermittent exotropia (IXT) with convergence insufficiency (CI) according to their response to preoperative monocular occlusion. This prospective study included 55 children who underwent slanted bilateral LR recession for IXT with CI. Patients were divided into two groups according to their response to preoperative monocular occlusion for 2 hours. The True CI group was defined as having near-distance differences of ≥10 PD before and after occlusion; the Masked CI group as having near-distance differences of <10 PD and ≥10 PD prior to and after occlusion. Slanted procedure reduced distance and near exodeviations from 32.1 PD and 43.0 PD to 3.5 PD and 4.4 PD, and collapsed near-distance differences from 10.9 PD to 1.0 PD at 3 years postoperatively. Cumulative probabilities of surgical success were 76%, and the mean recurrence was 50 months at 3 years postoperatively; the True CI and Masked CI groups showed cumulative success rates of 89% and 55%, respectively (p = 0.0052). Patients in the True CI group demonstrated surgical outcomes superior to those demonstrated by patients in the Masked CI group after slanted bilateral LR recession.

Long-term Results of Slanted Recession of Bilateral Lateral Rectus Muscle for Intermittent Exotropia with Convergence Insufficiency

PURPOSE

To evaluate the long-term efficacy of slanted lateral rectus recession in children for reducing distance and near exodeviation and near-distance deviation difference in intermittent exotropia with convergence insufficiency.

METHODS

The medical records of 53 patients with convergence insufficiency intermittent exotropia who underwent slanted bilateral lateral rectus recession performed by a single surgeon and received follow-up for more than 12 months were retrospectively analyzed. Deviation angles at 1 day, 1 week, 1 month, 3 months, 6 months, and 12 months postoperatively and on the last visit were reviewed. Surgical success was defined as postoperative residual distance and near deviation angles ≤8 prism diopters and a difference between the near and distance angles ≤8 prism diopters.

RESULTS

The mean duration of follow-up was 24 months (range, 12 to 61 months). On the last visit, the residual deviation angles were ≤8 prism diopters in 75.5% for distance, 62.3% for near, and 81.1% for the near-distance difference. Surgical success was achieved in 31 (58.5%) patients, and none of them manifested limitations in eye movements or diplopia at the last follow-up visit.

CONCLUSIONS

Slanted lateral rectus recession is an effective surgical method for reducing distance and near exodeviation and near-distance deviation difference in intermittent exotropia with convergence insufficiency.

Comparison of bilateral medial rectus plication and resection for the treatment of convergence insufficiency-type intermittent exotropia

PURPOSE

To compare the clinical outcomes of bilateral medial rectus plication and resection for the treatment of convergence insufficiency (CI)-type intermittent exotropia (IXT).

METHODS

Fifty-five patients with CI-type IXT were included in this prospective study and were followed for 6 months. The patients were randomized into two groups: the bilateral medial rectus plication (BMRP) group (n = 27) and the bilateral medial rectus resection (BMRR) group (n = 28). The eye examinations of each patient were carried out before the surgery and at 1 day and 1, 3 and 6 months postoperatively. The success rate, angle of deviation, stereoacuity, operative time and postoperative conjunctival swelling and redness score were analysed.

RESULTS

The mean deviation at distance at 1 day postoperatively was +6.6 ± 5.6 prism dioptres (PD) in the BMRP group, which was lower than the value of +10.8 ± 9.3 PD observed in the BMRR group (p = 0.046). There was more overcorrection in the BMRR group at first day after surgery. However, there were no significant differences in deviations or success rates were observed between the two groups at 1, 3 and 6 months after surgery (p > 0.05). The operative time in the BMRP (12.9 ± 1.4 min) group was shorter than that in the BMRR (14.7 ± 1.4 min) group (p < 0.001). Postoperative conjunctival swelling and redness were milder in the BMRP group than in the BMRR group (p < 0.001).

CONCLUSION

The BMRP surgery could be an alternative procedure to BMRR for the treatment of CI-type IXT with less immediate postoperative overcorrection and simpler, safer, less traumatic characteristics.

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.

Bilateral Lateral Rectus Recession for the Treatment of Recurrent Exotropia after Bilateral Medial Rectus Resection

PURPOSE

To evaluate the efficacy of bilateral lateral rectus muscle recession (BLR) to treat recurrent exotropia after bilateral medial rectus muscle resection (BMR).

METHODS

Twenty-four patients who underwent BLR for recurrent exotropia and were followed up for more than 6 months were included in this retrospective study. All of them had prior BMR. The angle of deviation, success rates, near stereopsis, and surgical effect of BLR were evaluated. Surgical success was defined as postoperative deviations ≤10 prism diopters (PD).

RESULTS

The overall mean follow-up time after reoperation for patients was 24.13 ± 15.01 months (range 6-60 months). The mean angle of deviation at distance was significantly reduced from -37.75 ± 14.93 PD to +1.50 ± 6.43 PD (p < 0.001). Twenty-two (91.6%) of 24 patients had successful outcomes, 1 (4.2%) had overcorrection, and 1 (4.2%) had undercorrection at the last follow-up. Improved stereopsis after reoperation was observed in 78.3% (18/23) of the patients. The mean surgical effect was 2.78 ± 0.71 PD/mm.

CONCLUSION

Based on our results, BLR could be an effective and safe method for treating recurrent exotropia after a moderate to large amount of BMR.

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.

Surgical outcomes of three different surgical techniques for treatment of convergence insufficiency intermittent exotropia

PurposeTo determine the outcomes of three different techniques of strabismus surgery in patients with convergence insufficiency intermittent exotropia (CI-X(T)).Patients and methodsSixty-seven patients with CI-X(T) with near-distance disparity (NDD) ≥10 prism diopter (PD) were included in this 1-year follow-up prospective study and were randomly divided into three groups: slanted bilateral LR recession (S-BLR) group in which 22 patients underwent bilateral slanting recession of the lateral rectus (LR) muscle, the I-RR group with 23 patients who underwent improved unilateral medial rectus (MR) resection and LR recession with the amounts of resection and recession biased to near and distance deviation, respectively, and the A-BLR group with 22 patients who underwent bilateral augmented LR recession based on the near deviation. A successful outcome at distant and near was defined as exodeviation between 10 PD of exophoria/tropia and 5 PD of esophoria/tropia. Cumulative probabilities of success, preoperative and postoperative distant, near deviations, and NDD among groups were analyzed and compared.ResultsThe success rate of distant exodeviation, near exodeviation, and NDD in the three groups after 1 year was statistically insignificant (P=0.054, 0.233, and 0.142, respectively). At the 1 year follow-up, vertical pattern strabismus (V and A patterns) was a feature of the S-BLR group, whereas the rate of postoperative overcorrection and undercorrection was significant in the A-BLR and I-RR groups, respectively.ConclusionThe success rate of correction of distant exodeviation, near exodeviation, and NDD was statistically indifferent among the three groups. However, each procedure has its specific postoperative concerns, which should be considered before implementing in patients with CI-X(T).

Early results of slanted recession of the lateral rectus muscle for intermittent exotropia with convergence insufficiency

The aim of this study was to evaluate the efficacy of slanted recession of the lateral rectus muscle for intermittent exotropia with convergence insufficiency. This prospective study included 31 patients who underwent slanted lateral rectus recession for intermittent exotropia with convergence insufficiency between June 2010 and June 2012. Following parameters were recorded and analyzed: patient sex, age, preoperative and postoperative near and distance ocular alignment, and changes in stereopsis. The mean age of the patients was 9.2 years. The preoperative mean deviation angle was 32.4 PD at distance and 43.4 PD at near. After 6 months, slanted lateral rectus recession reduced the deviation angles to 2 PD at distance and 3.4 PD at near. In addition, the mean difference between distance and near deviation angles was significantly reduced from 11 PD to 1.4 PD at 6 months postoperatively. Slanted lateral rectus recession for intermittent exotropia with convergence insufficiency in children successfully reduced the distance and near exodeviations and the near-distance difference without increasing the risk of long-term postoperative esotropia or diplopia.

Advances in surgery procedures for convergence insufficiency-type intermittent exotropia

Intermittent exotropia with convergence insufficiency is defined as a greater exodeviation measured at near than at distance of at least 10 prism diopters and it is harmful to binocular vision at earlier time. This paper mainly introduces three operation patterns including lateral rectus recession(s) with or without a slanting procedure, unilateral lateral rectus recession with medial rectus resection, and medial rectus resection(s) with or without a slanting procedure.

Surgical outcomes in convergence insufficiency-type exotropia

PURPOSE

To determine the efficacy of different types of strabismus surgeries in patients with convergence insufficiency (CI)-type exotropia, according to their response to diagnostic monocular occlusion.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Sixty-five patients with CI-type exotropia with near-distance differences of ≥10 prism diopters (PD) who underwent strabismus surgery.

METHODS

Patients were divided into 3 groups according to their response to monocular occlusion: (1) true-CI group: near-distance differences ≥10 PD before and after occlusion; (2) masked-CI group: near-distance differences <10 PD before occlusion and ≥10 PD after occlusion; and (3) pseudo-CI group: near-distance differences ≥10 PD before occlusion and <10 PD after occlusion. Either bilateral lateral rectus recession based on near measurements with 1 mm augmentation (BLR) or unilateral medial rectus resection based on the near deviation with lateral rectus recession based on the distant deviation (RR) was performed.

MAIN OUTCOME MEASURES

Cumulative probabilities of success, near-distance differences of exodeviation, rate of recurrence per person-year, and risk factors of recurrence.

RESULTS

There were 24 children in the true-CI group, 19 children in the masked-CI group, and 22 children in the pseudo-CI group. The cumulative probabilities of success at 2 years after BLR versus RR were 61% versus 100% in the true-CI group, 58% versus 100% in the masked-CI group, and 77% versus 71% in the pseudo-CI group. The RR procedure was significantly more successful than the BLR procedure in the true-CI and masked-CI groups.

CONCLUSIONS

Successful outcome in CI-type exotropia was closely related to the patients' response to monocular occlusion. In patients with CI-type exotropia maintained after monocular occlusion, unilateral resection-recession based on near-distance measurements is recommended.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.