Unilateral versus bilateral medial rectus recession

Long-term surgical outcomes of one-muscle vs. two-muscle horizontal strabismus surgery

PURPOSE

While horizontal strabismus surgery is generally considered to have favorable outcomes, success rates can vary by type of procedure. Our purpose is to compare the long-term outcomes of patients who underwent one-muscle vs. two-muscle horizontal strabismus surgery.

METHODS

This is a retrospective study comparing one-muscle to two-muscle strabismus surgery for small to moderate angle horizontal strabismus. Demographic data and eye exam parameters were compared at baseline and postoperatively (6 months up to 6 years). Surgical success was defined as a post-operative angle of 10 PD or less. We also compared outcomes by strabismus type: esotropia vs exotropia and adjusted the analysis for previous strabismus surgery.

RESULTS

Out of 89 patients with moderate angle horizontal strabismus (25 PD or less), 17 patients had a one-muscle operation, and 72 patients had two-muscle surgery. The mean age was 14.12 ± 9.30 years and 11.70 ± 11.30 years for the one-muscle and two-muscle groups, respectively (p = .74). The baseline characteristics of both groups were comparable. Follow-up time was 32.82 ± 26.93 months in one-muscle and 37.67 ± 23.81 in two-muscle groups (p = .29). Success rate was 70.6% for the one-muscle group and 68.10% for the two-muscle group (p = .69). Outcomes were similar when divided into esotropia and exotropia. The success rate was not affected by previous strabismus surgeries nor by the initial angle of deviation.

CONCLUSION

One-muscle and two-muscle horizontal strabismus surgery had similar long-term outcomes and did not differ by strabismus type nor by angle of deviation.

A Conservative Approach by Unilateral Maximal Single-Muscle Recession Surgery for the Treatment of Cyclic Esotropia

Purpose

Cyclic esotropia (alternate-day squint) is a poorly understood form of strabismus that mostly occurs at younger pediatric ages. It demonstrates classically a 48-hour cycle with 24 hours of manifest esotropia and 24 hours of orthotropia, which is conventionally managed by bilateral or unilateral 2-muscle surgery. We aimed to report a child with cyclic esotropia who was surgically treated by a conservative unilateral 1-muscle approach.

Methods

Case report.

Results

A 3.5-year-old girl presented to the strabismus department with an intermittent esodeviation for 2 years that became cyclic in the last 3 months. The diagnosis of primary classical cyclic esotropia was made after seeing her multiple times on different days. The girl was emmetropic bilaterally, had normal visual acuities in both eyes, and high-angle right esodeviation (45-50 ^Δ ) with normal laboratory and MRI results. Unilateral maximal single-muscle recession of the right medial rectus was performed, and the child was followed up for 9 months. The girl developed excellent alignment after the surgery both at distance and near without cyclic pattern, and near-normal stereopsis (by animals: 100 sec. of arc) with binocularity was reached. The girl did not experience under- or overcorrection nor have a recurrence postoperatively.

Conclusion

This is the first report of "one eye single-muscle" surgery for high-angle cyclic esotropia. Conservative unilateral medial rectus recession seems to be sufficient to permanently block the circadian rhythm and restore binocular fusion and stereopsis.

Infantile Esoropia: Management results and prognostic factors

BACKGROUND

Infantile esotropia is characterized by a significant deviation angle and a marked sensory perversion. Although the motor surgical results are satisfactory, the sensory results remain disappointing.

AIM

Our work aims to describe the methods of surgical management, its motor and sensory results as well as its prognostic factors.

METHODS

Retrospective study of 68 cases of infantile esotropia. All patients underwent a complete ophthalmologic examination and sensorimotor assessment. They were operated on, under general anesthesia, by the same surgeon. We assessed the motor and sensory results. The prognostic factors studied were age of onset, treatment delay, amblyopia severity, strabismus deviation angle, and presence of a vertical element.

RESULTS

The mean minimum angle of deflection was 38.6 ± 13.2D. Inferior oblique muscle hyper action was noted in 73.5% and a dissociated vertical deviation in 5.8%. Bilateral medial rectus muscle recession was the most performed surgery (60.2% of cases). The overall success rate was 94.11%. No patient acquired stereoscopic vision. Multivariate logistic regression analysis showed that preoperative nail (p = 0.007), immediate postoperative outcome (p <0.001) and surgical dosage (p = 0.009) were associated with long-term motor success.

CONCLUSION

The motor results of early esotropia surgery are generally satisfactory; the sensory results are often disappointing. Detecting poor prognostic factors improves operative results.

A Prospective Study of One-Muscle Surgery in 15-25 Prism Diopters Horizontal Comitant Strabismus in Adults

Purpose

To prospectively evaluate the results of one-muscle surgery in 15-25 prism diopters (PD) horizontal comitant strabismus in adults.

Patients and Methods

15-25 PD horizontal strabismus patients, comprising 25 exotropic (XT) patients and 11 esotropic (ET) patients, who underwent one-muscle recession by a single surgeon with a fixed surgical dosage were included in the study with a minimum follow-up of 3 months. The main outcome was a surgical success, which is defined as a residual deviation of <8 PD at the last examination. Other parameters include postoperative lateral incomitance and patient satisfaction. Postoperative lateral incomitance indicated a difference in deviation of >5 PD between the primary position and lateral gaze, or duction limitation at any visit. Patient satisfaction regarding cosmetic and functional outcomes was assessed by using a 5-point Likert scale.

Results

Successful alignment was obtained in 19 (76%) and 9 (81.81%) XT and ET patients (p = 1.00), with a median and interquartile range (IQR) of follow-up time of 3, 3-3 months and 3, 3-7 months, respectively. Postoperative lateral incomitance was observed in 8 (32%) XT patients and in 1 (9.09%) ET patient (p = 0.22). One XT patient and one ET patient who developed incomitance reported diplopia, which disappeared 3 months after surgery. One XT patient reported diplopia while gazing towards the operated eye whilst one ET patient reported diplopia occasionally which was unrelated to gaze direction. Patient satisfaction was based on Likert scale scores with 4.12 ± 0.97 in XT patients and 4.73 ± 0.65 in ET patients (p = 0.07).

Conclusion

One-muscle recession with a fixed surgical dosage was effective for treating small angle horizontal strabismus with a high rate of surgical success and patient satisfaction. Although postoperative lateral incomitance occurred, only a few patients developed symptomatic diplopia, which completely resolved 3 months after surgery.

Evaluation of Efficacy and Lateral Gaze Incomitance in Symmetrical and Asymmetrical Surgery for Concomitant Esotropia and Exotropia

Purpose

Evaluation of asymmetrical and symmetrical horizontal strabismus surgery as regards efficacy and postoperative lateral gaze incomitance.

Patients and Methods

This prospective comparative interventional case series study included 40 patients of age more than 3 years with alternating horizontal strabismus. Patients were divided according to the type of horizontal deviation into esotropia and exotropia groups, which were further subdivided into asymmetrical and symmetrical subgroups in each type. The surgery was defined as symmetrical procedure if the surgery was done on the same muscle in the two eyes and it was defined as asymmetric in recess-resect procedures in one eye, and three horizontal muscles surgery. Preoperative and postoperative measurements were done in primary position, right, and left gaze using alternate prism cover test and hand-held orthopedic goniometer.

Results

At the end of follow-up period, a statistically insignificant difference (P value = 0.8057) was present in the success rate between the asymmetrical and symmetrical subgroups of esotropia (90 and 86.67%, respectively) and it was 100% in both exotropia subgroups. Lateral gaze incomitance results were different between esotropia and exotropia subgroups. In esotropia, a statistically significant difference was reported at 1 month (0.009), which became insignificant at 6 months (0.077) and 12 months (0.077) between asymmetrical and symmetrical subgroups. In exotropia subgroups, there was a statistically insignificant difference in lateral gaze incomitance at 1, 6, and 12 months (P = 1).

Conclusion

Asymmetrical procedure had the same efficacy and success rate of symmetrical procedure for the correction of concomitant horizontal deviations in primary gaze without persistent postoperative lateral gaze incomitance, especially in exotropia.

Clinical Trial Registration

NCT04199286.

Association between esodeviation and primary open-angle glaucoma: the 2010-2011 Korea National Health and Nutrition Examination Survey

BACKGROUND/AIMS

To evaluate the association between strabismus and primary open-angle glaucoma (POAG) in a representative Korean population.

METHODS

A total of 11 114 participants aged 20 years or older in the Korea National Health and Nutrition Examination Survey database for the years 2010 through 2011 were reviewed. A standardised protocol was used to interview every participant and to perform comprehensive ophthalmic examinations. Glaucoma diagnosis was based on fundus photography and frequency-doubling technology perimetry results, according to the International Society of Geographical and Epidemiological Ophthalmology criteria. Ocular alignment was evaluated using the alternate prism and cover test, and clinically significant horizontal strabismus was defined as exodeviation of ≥15 prism dioptres (PD) and esodeviation of ≥10 PD. Univariate and multivariate regression analyses were used to evaluate the potential risk factors for POAG.

RESULTS

In the Korean population, subjects with clinically significant esodeviation had a much higher prevalence of POAG (12.32%) than those without clinically significant esodeviation (3.14%, p=0.016). After adjusting for age and intraocular pressure, clinically significant esodeviation was independently associated with POAG (OR 7.61, p=0.002).

CONCLUSION

Esodeviation was independently associated with POAG in the Korean population. This could be the result of, at least in part, ocular-adduction-induced greater strain on the temporal optic nerve head and peripapillary tissues, which makes eyes with esodeviation more vulnerable to POAG.

One-Muscle Strabismus Surgery: A Review

Proper management of a patient with small to moderate horizontal deviations continues to be challenging for the strabismus surgeon. The use of one-muscle surgery for comitant strabismus has been controversial because of concerns that it may result in a significant number of undercorrections and/or ocular incomitance. Recent literature on unilateral rectus muscle surgery has shown that this surgery is a safe and effective procedure for small and moderate angle horizontal deviations. It has the advantage of limiting surgery to one eye, reducing operative time and possible cost to the family, and leaving other muscles untouched in case repeat surgery is necessary. Larger studies need to be done in the future; however, this surgery should be considered as a primary approach in the treatment of small to moderate angle esotropia. [J Pediatr Ophthalmol Strabismus. 2018;55(5):288-292.].

The use of one muscle recession for horizontal strabismus

Purpose

To evaluate the outcomes of one muscle recession for horizontal comitant strabismus at a major referral hospital in the Middle East.

Method

Retrospective charts review of postoperative outcomes of 90 patients who had undergone one muscle recession for small to moderate angle esotropia or exotropia. Data were collected for age, vision, amblyopia, previous surgery or botulinum toxin injection, preoperative deviation, amount and type of one muscle surgery, and postoperative deviation at the initial and last (six months or more) postoperative visit. Successful alignment was defined as ±10 prism diopters (PD) of orthophoria.

Results

Sixty patients underwent medial rectus recession and 30 patients underwent lateral rectus recession. The average preoperative and last follow up deviation -respectively- was 24 ± 6.1 PD (15–35) PD and 14.62 ± 8.91 PD in the medial rectus recession group and 21.3 ± 5.1 PD (12–30) and 12.60 ± 8.74 in the lateral rectus recession group. The final success rates were 63.3% in both groups.

Conclusion

Single muscle strabismus surgery to correct horizontal strabismus had a variable outcome. Larger recession may help in achieving better outcomes. Properly designed prospective studies may help in identifying the factors affecting the outcomes of single muscle strabismus surgeries.

Prevalence and risk factors of strabismus in children and adolescents in South Korea: Korea National Health and Nutrition Examination Survey, 2008-2011

Purpose

To evaluate the prevalence and risk factors associated with horizontal strabismus in children and adolescents in South Korea.

Methods

A total of 5,935 children and adolescents 5–18 years of age who participated in the fourth and fifth Korean National Health and Nutrition Examination Survey (KNHANES IV-V) from July 2008 to December 2011 were evaluated and the prevalence of horizontal strabismus was estimated. Univariate and multivariate logistic regression analyses were conducted to determine the association between demographic, socioeconomic and clinical risk factors and clinically significant exodeviation (≥15 prism diopters [PD]) and esodeviation (≥10 PD).

Results

Among 5,935 eligible subjects, 84 subjects had clinically significant exodeviation and 13 had clinically significant esodeviation. The overall prevalence of clinically significant horizontal strabismus was 1.6% (95% confidence interval [CI], 1.2–2.1): 1.3% (95% CI, 1.0–1.7) for clinically significant exodeviation and 0.3% (95% CI, 0.1–0.6) for clinically significant esodeviation. Clinically significant exodeviation was associated with amblyopia (adjusted odds ratio [aOR], 6.45; 95% CI, 2.14–19.44), family history of strabismus (aOR, 4.91; 95% CI, 1.71–14.08) and astigmatism ≥1.0 D (aOR, 1.84; 95% CI, 1.13–2.98). Clinically significant esodeviation was associated with hyperopia (aOR, 12.16; 95% CI, 1.31–113.04) and amblyopia (aOR, 4.70; 95% CI, 1.12–19.81). Other demographic, socioeconomic, and clinical variables were not associated with strabismus.

Conclusion

This study provides data on the prevalence and independent risk factors for clinically significant exodeviation and esodeviation in a representative population of children and adolescents in South Korea.

Effect of vertical transposition of the medial rectus muscle on primary position alignment in infantile esotropia with A- or V-pattern strabismus

PURPOSE

To determine the effect of vertical displacement of muscle insertions on the surgical dose-response relationship in patients undergoing bilateral medial rectus recessions.

METHODS

Retrospective chart review of patients undergoing bilateral medial rectus recessions for correction of congenital esotropia with or without vertical displacement for A or V patterns. Patients were clustered into A pattern, V pattern, and "simple" (no pattern) groups. Strabismus angle at distance and near before and after surgery was recorded. Surgical dose-response relationships (in prism diopters/mm) were determined at the 6-month follow-up visit and compared.

RESULTS

A total of 55 patients (28 male and 27 female patients; mean age, 6.9 years; range, 2-17 years) were included. Of these, 28 had either A pattern (18) or V pattern (10), and 27 were in the simple group. Mean preoperative angle of deviation was 34Δ at distance and 40Δ at near. The surgical dose-response relationship was significantly greater (at both distance and near) in the A pattern group (2.43Δ/mm, distance [p=0.005]; 2.76Δ/mm, near [p=0.04]) than in the simple group (1.56Δ/mm, distance; 2.03Δ/mm, near). The surgical response in the V pattern group (1.96Δ/mm, distance [p=0.34]; 2.03Δ/mm, near [p=0.94]) was not significantly different from the simple group.

CONCLUSIONS

Upward displacement of the medial rectus muscles increased the surgical dose/response relationship in patients with A-pattern esotropia. A similar effect was not observed with downward displacement in patients with V-pattern strabismus. Surgeons should be aware of this enhanced response when planning surgery for A-pattern esotropia.

Outcome study of graded unilateral medial rectus recession for small to moderate angle esotropia

PURPOSE

To report an outcome study of 123 consecutive patients treated by graded unilateral medial rectus recession for small to moderate angle esotropia over an 8-year period with a minimum follow-up of 6 months.

METHODS

The records of patients who underwent unilateral medial rectus recession for constant esotropia measuring 15 to 35 prism diopters (PD) were reviewed. Unilateral medial rectus recession of 5.0, 5.5, 6.0, 6.5, and 7.0 mm was performed for 15 to 18, 19 to 20, 21 to 25, 26 to 30, and 31 to 35 PD of esodeviation, respectively. Postoperative follow-up was at least 6 months. Successful alignment was defined as ±5 PD of orthophoria in primary and lateral gaze while viewing distant and near accommodative targets.

RESULTS

The eyes of 96.8% of the patients were successfully aligned and the average deviation corrected was 17.33 ± 1.16 PD for 5 mm, 18.57 ± 2.51 PD for 5.5 mm, 23.67 ± 4.91 PD for 6 mm, 26.68 ± 3.87 PD for 6.5 mm, and 31.93 ± 3.26 PD for 7 mm unilateral medial rectus recession at 6-month follow-up. Seventy-four patients (83.2%) with more than 6 months of follow-up achieved successful alignment, 14 (15.7%) were under-corrected, and 1 (1.1%) was overcorrected.

CONCLUSION

Successful alignment was achieved in most esotropic patients treated by the graded unilateral medial rectus recessions. The surgical guidelines provide a reference for the treatment of small to moderate angle esotropia.

One muscle strabismus surgery

PURPOSE OF REVIEW

To describe recent evidence from the literature regarding one muscle strabismus surgery for small- to moderate-angle horizontal deviations.

RECENT FINDINGS

The use of one muscle surgery for comitant strabismus had been controversial because of concerns that it may result in a significant number of undercorrections and/or produce ocular incomitance. Recent evidence in unilateral lateral rectus recession for exotropia, unilateral medial rectus recession for esotropia, and unilateral rectus resections for undercorrected or recurrent strabismus and convergence or divergence insufficiency suggests that unilateral rectus muscle surgery is a safe, effective and predictable procedure for small- to moderate-angle horizontal deviations. Future prospective, comparative studies with larger samples in unilateral rectus muscle surgery are still needed.

SUMMARY

Unilateral rectus muscle surgery is a safe, effective and predictable treatment for small- to moderate-angle horizontal deviations. This procedure limits surgery to one eye, leaves other muscles untouched for repeat surgery, and therefore, should be considered as a primary or alternative approach in the treatment of small- to moderate-angle strabismus.

Bilateral vs unilateral medial rectus resection for recurrent exotropia after bilateral lateral rectus recession

PURPOSE

To compare outcomes after bilateral and unilateral medial rectus (BMR/UMR) resection for the treatment of recurrent exotropia after bilateral lateral rectus (BLR) muscle recession.

DESIGN

Retrospective, cohort study.

METHODS

Forty-four patients underwent BMR resection (BMR group) or UMR resection (UMR group) for recurrent constant exotropia of 25 prism diopters (PD) or less at distance after undergoing BLR muscle recession for intermittent exotropia in an institutional setting. The main outcome measures were final success rates and improvement in stereopsis and were compared between the groups. The risk factors for recurrence after reoperation also were evaluated. Secondary outcome measures were evaluated based on the drift of ocular alignment toward exodeviation after surgery (exodrift) from postoperative day 1.

RESULTS

Thirteen (54%) of 24 patients in the BMR group had successful outcomes, 10 (42%) had overcorrection, and 1 (4%) had undercorrection at the last follow-up examination. Sixteen (80%) of 20 patients in the UMR group had successful outcomes, 2 (10%) had undercorrection, and 2 (10%) had overcorrection. The incidence of successful outcomes at the last follow-up examination and the incidence of recurrence were not significantly different between the 2 groups, whereas the incidence of overcorrection was significantly higher in the BMR group (P = .017).

CONCLUSIONS

Large UMR resection is a safe and effective procedure in the treatment of small to moderate angles of recurrent exotropia after BLR muscle recession. The overcorrection rate was significantly lower after UMR resection than it was after BMR resection.