Horizontal Rectus Muscle Surgery Research Articles

Short-Term Morpho-Functional Changes before and after Strabismus Surgery in Children Using Structural Optical Coherence Tomography: A Pilot Study.

To evaluate the immediate alterations in the thickness of the macular ganglion cell-inner plexiform layer (mGCIPL), peripapillary retinal nerve fiber layer (RNFL), inner retinal layer (IRL), and outer retinal layer (ORL) using spectral domain optical coherence tomography (SD-OCT) subsequent to strabismus surgery in pediatric patients diagnosed with horizontal esotropia. Twenty-eight eyes from twenty-one child patients who had undergone uncomplicated horizontal rectus muscle surgery due to strabismus were included. Measurements of RNFL, mGCL-IPL, IRL, and ORL using structural OCT were conducted both before the surgery and one month after the surgical procedure. Importantly, a control group comprising 14 healthy eyes, matched for age and significant refractive error (<3.00 diopters), was included in the current analysis. Our analysis indicated no significant disparity before and after surgery in terms of best-corrected visual acuity (BCVA), RNFL, IRL, and ORL. Conversely, concerning the macular ganglion cell layer-inner plexiform layer analysis, a substantial increase in mGCL-IPL was observed following the surgical intervention. The mean mGCL-IPL measured 60.8 ± 9.2 μm at baseline and 66.1 ± 13.2 μm one month after the surgery (p = 0.026). Notably, comparison between the strabismus group at baseline and the healthy group revealed a significant reduction in mGCL-IPL in the strabismus group (60.8 ± 9.2) compared to the healthy control group (68.3 ± 7.2; p = 0.014). Following strabismus surgery, our observations pointed towards a thickening of the mGCL-IPL layer, which is likely attributable to transient local inflammation. Additionally, we identified a significant differentiation in the mGCL-IPL complex between the pediatric patient group with strabismus and the control group.

Investigation of alterations in retrobulbar hemodynamics and their correlation with choroidal thickness after strabismus surgery.

To evaluate the changes in retrobulbar circulation after strabismus surgery and to assess the relationship of these changes with choroidal thickness (CT). This prospective study included 26 eyes of 26 patients who underwent strabismus surgery and 15 eyes of 15 healthy individuals as control group. The patients who had single horizontal muscle surgery were included in Group 1 (n = 14); and those who had surgery on both horizontal muscles were included in Group 2 (n = 12). Peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index (RI) and pulsatility index (PI) of ophthalmic artery (OA), posterior ciliary artery (PCA), and central retinal artery (CRA) were measured using Color Doppler Ultrasonography. Subfoveal CT was measured via Optical Coherence Tomography. All measurements were obtained preoperatively, at 1st week and 1st month after surgery. There were no differences regarding preoperative blood flow velocity parameters among the groups. OA RI increased significantly at 1st week and 1st month after surgery in Group 1 and 2 (P = 0.029 and P = 0.045, respectively). There was a significant increase in PCA PSV at 1st week in Group 1 (P = 0.002). There was no difference between the mean preoperative and postoperative CT among the 3 groups. A negative correlation between the percentage changes of CT and CRA EDV was found in Group 2 (P = 0.011). Single and double horizontal rectus muscle surgery have a measurable effect on retrobulbar hemodynamics but these changes do not correlate with CT.

Outcomes and Factors Associated with Successful Strabismus Surgery for Abducens Nerve Palsies: A Retrospective Study and Literature Review.

Several studies reported surgical outcomes for abducens nerve palsy, but information on factors that affect treatment success remains lacking. These factors are crucial for developing a treatment plan and providing disease counseling. This study aimed to investigate the outcomes of strabismus surgery for abducens nerve palsy and determine the factors that influence its success, including a review of relevant literature. This retrospective analysis included abducens nerve palsy cases, focusing on surgical interventions and relevant patient data, at the outpatient clinics of Phramongkutklao Hospital from April 1, 2012, to April 30, 2022. A relevant literature review included the surgical success rate and factors that influence surgical outcomes. This study enrolled 32 patients, including 19 with partial and 13 with complete abducens nerve palsy. The overall success rate of strabismus surgery was 78.1%. Trauma was the leading cause of abducens nerve palsy in this population (28.13%). Fisher's exact and Mann-Whitney U-tests revealed that shorter abducens nerve palsy onset and smaller preoperative angle were significantly associated with successful surgical outcomes of strabismus surgery among the groups. In contrast, subgroup analysis revealed that only preoperative smaller angles were significantly associated with good surgical outcomes in horizontal strabismus surgery. However, the vertical rectus muscle transposition group demonstrated no significant factors. The literature review revealed that the success rate of surgery in abducens nerve palsy was 25%-82.6% for horizontal rectus muscle surgery and 46.2%-91% for rectus muscle transposition. The surgical success rate for abducens nerve palsy reached 78.1%, including 78.95% for partial and 76.92% for complete abducens nerve palsy. Notably, a shorter onset preceding surgery and a smaller preoperative angle significantly correlated with successful surgical outcomes one year postoperatively.

Acquired comitant esotropias – comparison of surgical outcomes of accommodative vs non-accommodative types

ABSTRACT Purpose: To compare the motor and sensory outcomes of strabismus surgery and the factors affecting surgical success in acquired acute non-accomodative esotropia (ANAET) and partially accommodative refractive esotropia (pARET). Methods: A retrospective chart review of patients with ANAET and pARET who underwent unilateral or bilateral horizontal rectus muscle surgery between January 2020 and December 2021 was conducted. Patients with postoperative follow-up of at least six weeks were included. Patients with pattern deviation, lateral incomitance, and near-distance disparity were excluded. Motor success was defined as a postoperative deviation within eight prism diopters of orthophoria. Sensory success was defined as presence of binocular single vision (BSV) for both distance and near (Worth four dot test). The effect of factors like age at onset, age at surgery, amblyopia before surgery, duration of squint before treatment, presence or absence and magnitude of vertical deviation, preoperative angle of deviation, and spherical equivalent on the motor and sensory success in each group were analyzed and compared. Results: 38 patients with ANAET and 33 patients with pARET were included. The mean age of onset of esotropia was 8.55 ± 4.65 years and 4.39 ± 2.27 years (p < .001) and the mean age at surgery was 10.62 ± 4.99 years and 7.89 ± 2.84 years (p = .006) in the ANAET and the pARET group respectively. The mean duration of the final follow-up was 38.51 weeks in the ANAET and 48.68 weeks in the pARET group (p = .089). Patients were successfully aligned for both distance and near in 81.5% of patients in the ANAET and 78.9% of patients in the pARET group at the final follow-up (p. 0.775). A BSV for both distance and near at the final follow-up was seen in 81.2% vs 66.6% of patients in the ANAET and the pARET group respectively (p = .25). A good near stereoacuity (<120 arcsecs) was seen in 60.6% and 41.9% of the ANAET and the pARET groups respectively (p = .175). The percentage of patients in the ANAET group who had orthophoria, any esodeviation, and any exodeviation for distance at the final follow-up was 63.1%, 34.2% and, 2.6%. The percentage of patients in the pARET group in similar categories was 36.3%, 42.4% and, 21.2%. None of the demographic and preoperative factors were found to affect the surgical outcomes in the two groups. Conclusions: The motor and sensory outcomes were similar in the two groups. A higher proportion of ANAET patients remained orthophoric during the follow-up. The patients in the pARET group showed a tendency toward exodrift.

Changes in retinal and choroidal blood flow after one or two horizontal rectus muscle surgeries by optical coherence tomography angiography

Purpose To evaluate the retinal and choroidal microvasculature after one or two horizontal rectus muscle surgeries in strabismus patients using swept-source optical coherence tomography angiography (SS-OCTA). Methods 30 eyes of 26 patients who underwent horizontal rectus muscle surgery were included in this study. Group A, A’ and Group B , B’ respectively consisted preoperative and postoperative measurements of patients who underwent one or two horizontal rectus muscle surgeries. We analyzed the vessel density (VD) of the superficial vascular complex (SVC), the deep vascular complex (DVC), the choriocapillary layer (CC), choroidal vascular index (CVI), choroidal thickness (T-Ch) and retinal nerve fiber layer thickness (T-RNFL) preoperatively, and one week postoperatively. Results Only in the nasal sector of the perifoveal zone, the VD in SVC demonstrated a significant increase in Group A’ (p = 0.027). There was a statistically significant difference in the VD changes of SVC between Group A and Group B (p = 0.043). The VD in DVC did not change significantly in the whole macular compared with the preoperative. Moreover, in both Group A’ and Group B’, the VD in CC showed a reduction in a single sector of the parafoveal area (p < 0.05). Group A’ have increased CVI in the nasal sector of the perifoveal region (p = 0.008). In addition, the T-Ch increase in the perifoveal region was more significant in Group B’ than in Group A’ (p < 0.05). Group A’ showed statistically significant decreases in T-RNFL in the foveal and parafoveal regions (p < 0.05). Conclusion This study revealed that the increase in choroidal thickness was more significant after two rectus muscle surgery. In addition, there were microvascular changes in sectional macular regions after strabismus surgery. OCTA is an excellent way to study the impact of strabismus surgery on the macular structure and blood flow.

Cirugía monocular de 4 músculos extraoculares para la exotropía monocular de gran ángulo

IntroductionRecurrent exotropia is common following surgery for monocular large angle constant sensory exotropia. Surgery is usually limited to operations on the affected eye. Simultaneous oblique weakening surgery may enhance the effect of the horizontal rectus muscles surgery by decreasing the abducting forces. We report the results of simultaneous oblique muscle weakening procedures combined with ipsilateral horizontal rectus muscle surgery constant monocular exotropia greater than 35 prism diopters (PD). MethodsRetrospective case series of patients who underwent unilateral lateral rectus recession combined with medial rectus muscle resection and simultaneous weakening of both ipsilateral oblique muscles. Primary outcome measure was ocular alignment in primary position. ResultsTwelve eyes of 12 patients were included. The mean preoperative exotropia improved from 57.9±15.1 (range 35–80; median 60PD) to 3.3±5.5 (range 0–16; median 0PD) postoperatively (p<0.005). Two (66%) patients with a pre-existing vertical deviation had resolution of their vertical misalignment postoperatively. At the last postoperative follow up 92% of the patients had an exodeviation of 10PD or less (range 0–16PD median 0PD), and 7 (58%) measured near and distance orthotropia. Postoperative abduction measured −0.6±1 (0 to −3) and adduction −0.4±0.7 (0 to −2). ConclusionWeakening the ipsilateral oblique muscles may enhance the effect of the horizontal rectus muscles surgery by decreasing the abducting vectorial forces when operating for a large angle monocular exotropia. As an additional potential advantage, oblique muscle surgery may be used simultaneously to address associated vertical deviations.

Unilateral four muscle surgery for extra-large monocular exotropia

IntroductionRecurrent exotropia is common following surgery for monocular large angle constant sensory exotropia. Surgery is usually limited to operations on the affected eye. Simultaneous oblique weakening surgery may enhance the effect of the horizontal rectus muscles surgery by decreasing the abducting forces. We report the results of simultaneous oblique muscle weakening procedures combined with ipsilateral horizontal rectus muscle surgery constant monocular exotropia greater than 35 prism diopters (PD). MethodsRetrospective case series of patients who underwent unilateral lateral rectus recession combined with medial rectus muscle resection and simultaneous weakening of both ipsilateral oblique muscles. Primary outcome measure was ocular alignment in primary position. ResultsTwelve eyes of 12 patients were included. The mean preoperative exotropia improved from 57.9 ± 15.1 (range 35–80; median 60 PD) to 3.3 ± 5.5 (range 0–16; median 0 PD) postoperatively (p < 0.005). Two of 3 patients with a pre-existing vertical deviation had resolution of their vertical misalignment postoperatively. At the last postoperative follow up 92% of the patients had an exodeviation of 10 PD or less (range 0–16 PD median 0 PD), and 7 (58%) measured near and distance orthotropia. Postoperative abduction measured −0.6 ± 1 (0 to −3) and adduction −0.4 ± 0.7 (0 to −2). ConclusionWeakening the ipsilateral oblique muscles may enhance the effect of the horizontal rectus muscles surgery by decreasing the abducting vectorial forces when operating for a large angle monocular exotropia. As an additional potential advantage, oblique muscle surgery may be used simultaneously to address associated vertical deviations.

A Comparative Study of Surgical Outcomes between the Adjustable Suture Technique and Conventional Technique in Strabismus Surgery

Objective: To compare the success rate between adjustable suture technique and conventional technique in rectus muscle surgery. Materials and Methods: The present study was a retrospective review of patients aged 10 and above underwent rectus muscle surgery between 2010 and 2018. Patients were classified into two groups according to the surgical techniques, the adjustable group and the conventional group. Preoperative and postoperative orthoptic evaluation including angle of deviation, sensory outcomes, and reoperation rate were collected. The primary outcome was surgical success rate at two years postoperatively, with success defined as ocular alignment within 10 prism diopters (PD) for horizontal rectus muscle surgery or within 5 PD for vertical rectus muscle surgery. The secondary outcome was reoperation rate and binocular functions improvement two years post-operation. Results: One hundred fifteen cases in the adjustable group and 90 in the conventional group were identified. Patients in the adjustable group had a higher success rate achieving the target angle after six months, one year, and two years post-operation compared to the conventional group at 77.4% versus 70% (p=0.23), 73.9% versus 65.6% (p=0.19), and 72.2% versus 60% (p=0.066), respectively, but there was no statistically significant difference. Sensory improvement was seen in 43.4% of patients in the conventional group and 42.6% in the adjustable group (p=0.54). Median stereopsis improvement was seen in both groups at 80 to 45 seconds of arc in the adjustable group and 100 to 60 seconds of arc in the conventional group (p=0.67). The reoperation rate was 18.9% in the conventional group and 19.1% in the adjustable group (p=0.97). Conclusion: The adjustable suture technique presented a superior success rate compared to conventional technique though there was no statistically significant difference. A longer follow-up period and larger sample size might be needed to demonstrate statistically significant difference between the two techniques. No significant difference in binocular functions, sensory improvement, or reoperation rate was seen in the present study. Keywords: Strabismus surgery; Adjustable suture; Conventional suture; Surgical outcome

Strabismus Surgery in Orthophoric Patients With Symptomatic, Asymmetric Vertical or Horizontal Incomitance

To report the indications, operative strategies, and surgical outcomes of patients who undergo vertical and horizontal rectus muscle surgery for incomitant strabismus despite being orthophoric in primary gaze. Retrospective, interventional case series. The setting for this study was an academic practice at Boston Children's Hospital. The patient population comprised 8 orthophoric patients who underwent strabismus surgery to treat vertical/horizontal incomitance. Observation procedures included review of surgical strategies, strabismus measurements in diagnostic gaze positions, and development of postoperative diplopia. The main outcome measures were preserved single vision in primary gaze, comitance, reoperation rate, and patient/surgeon satisfaction. Surgical strategies included the following: (1) simultaneous recession of ipsilateral antagonist rectus muscles; (2) recession or resection of 1 rectus muscle with balancing surgery on the fellow eye; (3) restricting the range of 1 muscle (combined resection and recession or posterior fixation suture); and (4) creating an acceptable deviation in primary gaze. Mean follow-up was 5.4 months (median, 2 months; range, 2-25 months). No patient had new-onset primary gaze diplopia. The median incomitance improved by 9.5 prism diopters. No patient required additional surgery. Patient satisfaction and surgeon assessment of outcomes were high. Although the risk of operating on orthophoric patients with incomitant strabismus may discourage surgeons from offering treatment, the use of specific strategies to address incomitance can preserve alignment in primary gaze while improving patient satisfaction. These strategies may also benefit patients with incomitant strabismus that is symptomatic in primary gaze.

Unilateral four-muscle surgery for large monocular constant sensory exotropia

Recurrent exotropia is common following horizontal rectus muscle surgery for monocular constant sensory exotropia. Surgery is limited to avoid operating on the better-seeing eye. Simultaneous oblique weakening surgery may enhance the effect of the horizontal rectus muscles surgery by decreasing the abducting oblique force. We report the results of simultaneous inferior and superior oblique muscle weakening procedures combined with horizontal muscle recession/resection for large angle constant monocular sensory exotropia greater than 35Δ.

Pattern Strabismus in a Tertiary Hospital in Southern China: A Retrospective Review.

Background and objectives: To analyze demographic and clinical features of pattern strabismus patients and assess the relationship among these clinical variables and risk factors. Materials and Methods: Medical records of pattern strabismus patients who had undergone strabismus surgery at our center between 2014 and 2019 were retrospectively reviewed. Data collected included gender, age at onset, age at surgery, refraction, Cobb angle, pre- and post-operative deviations in the primary position, up- and downgaze, angle of ocular torsion, type/amount of pattern, grade of oblique muscle function and presence/grade of binocular function. To verify the clinical significance of the Cobb angle, 666 patients who had undergone surgery within one week after ocular trauma between 2015 and 2021 were enrolled as controls. Results: Of the 8738 patients with horizontal strabismus, 905 (507 males and 398 females) had pattern strabismus, accounting for 10.36%. Among these 905 patients, 313 showed an A-pattern and 592 showed a V-pattern. The predominant subtype was V-exotropia, followed by A-exotropia, V-esotropia and A-esotropia. Over half of these patients (54.6%) manifested an A- or V-pattern in childhood. The overall mean ± SD Cobb angle was 5.03 ± 4.06° and the prevalence of thoracic scoliosis was 12.4%, both of which were higher than that observed in normal controls (4.26 ± 3.36° and 7.8%). Within A-pattern patients, 80.2% had SOOA and 81.5% an intorsion, while in V-pattern patients, 81.5% had IOOA and 73.4% an extorsion. Patients with binocular function showed decreases in all of these percent values. Only 126 (13.9%) had binocular function, while 11.8% of A-pattern and 15.1% of V-pattern patients still maintained binocular function. Pre-operative horizontal deviation was negatively correlated with binocular function (r = −0.223, p < 0.0001), while the grade of oblique muscle overaction was positively correlated with the amount of pattern (r = 0.768, p < 0.0001) and ocular torsion (r = 0.794, p < 0.0001). There were no significant correlations between the Cobb angle and any of the other clinical variables. There were 724 patients (80.0%) who had received an oblique muscle procedure and 181 (20.0%) who received horizontal rectus muscle surgery. The most commonly used procedure consisted of horizontal rectus surgery plus inferior oblique myectomy (n = 293, 32.4%), followed by isolated horizontal rectus surgery (n = 122, 13.4%). Reductions of pattern were 14.67 ± 6.93 PD in response to horizontal rectus surgery and 18.26 ± 7.49 PD following oblique muscle surgery. Post-operative deviations were less in V- versus A-pattern strabismus. Post-operative binocular function was obtained in 276 of these patients (30.5%), which represented a 16.6% increase over that of pre-operative levels. The number of patients with binocular function in V-pattern strabismus was greater than that of A-pattern strabismus (p = 0.048). Conclusions: Of patients receiving horizontal strabismus surgery, 10.36% showed pattern strabismus. In these patients, 54.6% manifested an A- or V-pattern in childhood, and V-exotropia was the most frequent subtype. Pattern strabismus patients showed a high risk for developing scoliosis. Cyclovertical muscle surgery was performed in 724 of these patients (80.0%), and horizontal rectus surgery was effective in correcting relatively small levels of patterns. Binocular function represented an important factor as being involved with affecting the occurrence and development of pattern strabismus.

Alterations of lower- and higher-order aberrations after unilateral horizontal rectus muscle surgery in children with intermittent exotropia: A retrospective cross-sectional study.

This retrospective, cross-sectional study investigated changes in corneal lower- and higher-order aberrations that cause visual disturbance after lateral rectus recession and medial rectus resection in children. Eighty-five eyes of 85 patients (44 boys; 8.64±2.88 years) who underwent lateral rectus recession and medial rectus resection to correct intermittent exotropia were assessed. The Galilei G4 Dual Scheimpflug Analyzer was used for wavefront analysis. Risk factors (age, sex, amount of surgery, preoperative axial length, preoperative intraocular pressure) were determined. Outcome measures included simulated and ray-tracing mode keratometry with secondary defocus, oblique, and vertical astigmatism (for lower-order aberrations) and the root mean square, 3rd-order vertical and horizontal coma, oblique and horizontal trefoil, 4th-order spherical aberration, oblique and vertical secondary astigmatism, and oblique and vertical quadrafoil (2nd‒8th sums) (for higher-order aberrations). Myopic with-the-rule changes in low-order aberrations and increases in simulated and ray-tracing mode keratometry during the 3 months following lateral rectus recession and medial rectus resection were attributed to muscle healing and stability changes. High-order aberrations altered in the week following surgery almost returned to normal within 3 months. Axial length, the amount of surgery, age, and sex affected astigmatism due to differences in patients' scleral states. Clinicians should consider changes in high-order aberrations of young individuals who underwent lateral rectus recession and medial rectus resection and may not be able to verbalize changes in vision.

Influence of one or two horizontal muscle surgeries on OCT findings

ABSTRACT We investigate the effects of differences between one or two horizontal rectus muscle surgeries (recession ± resection) on the central macular thickness (CMT), subfoveal choroidal thickness (SFCT), and retinal nerve fiber layer (RNFL). Measurements of the CMT, SFCT, and RNFL in patients who underwent horizontal rectus muscle surgery were obtained using optical coherence tomography (OCT). Patients were grouped as those who had undergone rectus muscle recession surgery (Group 1) and those who had undergone rectus muscle recession + resection surgery (Group 2). The CMT, SFCT, and RNFL in patients were measured preoperatively and 1 day, 1 week, 1 month, 3 months, and 6 months postoperatively. A total of 65 eyes of 50 patients were analyzed retrospectively. The average age of the 25 patients in Group 1 was 8.96 ± 7.966 years (min 3, max 38). The average age of the 25 patients in Group 2 was 15.17 ± 6.806 years (min 2, max 34). The comparison of the preoperative and the 1-day and 1-week postoperative values revealed an increase in CMT and SFCT in Group 1 and Group 2. There were no significant differences between the two groups. It was observed that this increase reached the preoperative values after 1–3 months and 6 months in both groups. There was no statistically significant change in the RNFL. Rectus muscle surgery (recession±resection) caused an increase in CMT and SFCT in the early stage, which was possibly caused by the altered choroidal microcirculation resulting from mechanical traction during surgery and by postoperative inflammation. There was no difference between one or two muscle surgeries.

Brown syndrome: clinical features and results of superior oblique tenotomy.

This study was conducted to further define the specific clinical characteristics of patients with Brown syndrome and evaluate the outcomes of superior oblique tenotomy in its surgical management. A retrospective analysis of the medical charts of 45 patients with Brown syndrome was performed, which revealed that 11 patients underwent superior oblique tenotomy due to abnormal head posture and/or hypotropia and 1 patient underwent bilateral superior oblique tendon elongation with a silicone band due to abnormal head posture. In the last patient, silicone bands were removed at the postoperative 3rd month due to the lack of improvement in the abnormal head posture and the limitation of elevation in adduction. Simultaneous horizontal rectus muscle surgery was performed in four patients. There was a predominance of female gender, right eye, congenital form, unilaterality, A-pattern, and an abnormal head posture type with a combination of chin up and head tilting. Bilateral form was observed only in female patients. Amblyopia was detected in two patients. Among patients aged >5 years, 40% had reduced stereopsis. Abnormal head posture was found in 60% of patients. More than half of them were diagnosed with a vertical and/or horizontal deviation. Tenotomy procedure eliminated the abnormal head posture in all patients and significantly improved the mean limitation of elevation in adduction and hypotropia (p=0.001, p=0.012). Two patients developed inferior oblique overaction in the operated eye. There was complete spontaneous resolution in two patients. The clinical features of patients with Brown syndrome in our study are considerably consistent with those of previous reports. The present study demonstrated the effectiveness of superior oblique tenotomy with less overcorrection in the surgical treatment of Brown syndrome.

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

To compare the results of surgery for constant and intermittent exotropia, to determine factors affecting surgical success, and to evaluate the effect of horizontal rectus muscle surgery on distance-near incomitance. In this retrospective study of 291 Scandinavian patients, inclusion criteria were surgery for constant (n = 101) or intermittent (n = 190) exotropia with no vertical deviation, no previous strabismus surgery, and available postoperative follow-up data. Medical records of patients (age: 3 to 85 years) undergoing surgery were reviewed. Surgical success was defined as postoperative esodeviation of less than 5 prism diopters (PD) to exodeviation of 10 PD or less. Surgical success was 70% in constant exotropia and 80% in intermittent exotropia (P > .05). At follow-up 1.5 years after surgery, a significant drift was found in intermittent exotropia (P < .05). Different surgeons, spherical equivalents, anisometropia, amblyopia, gender, and age had no effect on surgical success (P > .05). The surgical success rate increased with decreasing preoperative angle (P < .05). Resection of the medial rectus muscle had a greater effect on the near deviation, whereas recession of the lateral rectus muscle had a greater effect on the distance deviation (P < .05). Surgical success was equally good in constant and intermittent exotropia, but better long-term stability was observed following surgery for constant exotropia. The only factor affecting surgical success was the preoperative deviation, with smaller deviations having a better outcome. A distance-near incomitance may be an important consideration in choosing the magnitude of medial versus lateral rectus muscle surgery. [J Pediatr Ophthalmol Strabismus. 2021;58(1):34-41.].

Anterior and nasal transposition of inferior oblique muscle

We report the case of a 20-year-old woman who presented with residual esotropia, dissociated vertical deviation (DVD), and inferior oblique over-action (IOOA) who underwent horizontal rectus muscle surgery and anterior and nasal transposition of the inferior oblique muscle. Postoperatively, she was orthotropic and showed resolution of DVD and IOOA providing an excellent motor outcome.

Changes in Corneal Topography and Clinical Refraction Following Horizontal Rectus Muscle Surgery

Objectives. Refractive changes have been studied after muscle surgery in literature but most results are inconsistent.It has been postulated that changes in corneal tension after muscle surgery may cause a change in corneal curvatureresulting in the change in refraction postoperatively. This study investigated changes in corneal topography andclinical refraction after horizontal rectus muscle surgery.&#x0D; Methods. Twenty-one eyes of 13 patients underwent horizontal rectus muscle surgery via limbal approach. Manifestrefraction, cycloplegic refraction, and corneal topography were measured preoperatively, and postoperatively at day 1and weeks 1, 2, 4 and 8. The proportion of subjects with at least 0.5 D change from preoperative measurements and the proportion of subjects that needed new prescription postoperative were also computed. Analysis of the results were done using the Friedman test to identify significant differences among measurements at different time periods with post-hoc analysis utilized to identify specific time periods with significant changes from preoperative measurements.&#x0D; Results. Mean corneal keratometry, horizontal, vertical, and oblique astigmatism, obtained topographically showed nosignificant difference from preoperative measurements. The statistically significant difference in corneal astigmatismin the recession group at day 1, week 4 and week 8 postoperatively was not confirmed when converted to powervectors in both vertical/horizontal (J0) and oblique (J45) astigmatism. Clinical refraction showed a transient myopicshift in spherical equivalent, statistically significant only on postoperative day 1 in the recession group. There was nostatistically significant difference in clinical astigmatism. There was ≥ 0.5 D change in spherical equivalent in 60% inboth study groups by the end of follow-up. The shift in J0 was more than 10% in the recession group. More than fiftypercent (52.4%) needed new prescription for glasses.&#x0D; Conclusion. No statistically significant change in corneal topography and clinical refraction following horizontal rectusmuscle surgery were found. Patients should still be refracted at least 2 weeks postoperatively to check if there is aneed for change in prescription glasses to improve alignment and/or improve vision.

Analysis of astigmatism outcomes after horizontal rectus muscle surgery in patients with intermittent exotropia.

This study examined the factors affecting corneal curvature change after lateral rectus recession and medial rectus resection surgery in patients with intermittent exotropia. This was a retrospective cross-sectional study in intermittent exotropia patients who underwent rectus resection surgery. The study involved 41 male and 42 female patients (mean age: 9.55 ± 5.03 years, range: 3-28 years). Corneal astigmatism analysis was performed using the Galilei G4 Dual Scheimpflug Analyzer. The values of simulated and ray tracing corneal keratometry (K) of astigmatism, including axis changes, were determined preoperatively and at 1 week and 3 months postoperatively. The factors found to affect corneal curvature change were sex, extent of surgery, and axial length. Simulated and ray tracing changes were significant preoperatively and at 1 week and 3 months after rectus resection surgery (p < 0.05); however, there were no differences in astigmatism (D) at any time. The spherical equivalent had a myopic change after rectus resection surgery with cycloplegic refraction, and in ray tracing mode, flat K was decreased at 1 week from baseline and increased 3 months later. Steep, mean K, and axis increased continuously from baseline to 1 week and 3 months. Astigmatism, in contrast, was increased at 1 week, but decreased at 3 months, with no return to baseline. Univariable linear regression analyses showed that the extent of surgery had an effect on flat K change and that sex had an effect on steep K and axis. Additionally, axial length affected steep K and astigmatism, while age had no effect on any variable. Ray tracing values were significantly different from simulated values. In ray tracing mode, rectus resection surgery may result in astigmatism shifted toward with-the-rule, and myopic changes may be caused by differences in thickness and flexibility of the sclera. Notably, age did not affect any variable.

Tendon elongation with bovine pericardium in strabismus surgery\u2014indications beyond Graves\u2019 orbitopathy

BackgroundFor some patients with complex ocular motility disorders, conventional strabismus surgery is insufficient. Surgery with tendon elongation allows correction of larger angles and maintains a sufficient arc of contact for rectus muscles. This study reports results for tendon elongation with bovine pericardium (Tutopatch®) in indications other than Graves’ orbitopathy in which it is already widely used.MethodsWe reviewed the records of all patients who underwent surgery with Tutopatch® in our institution. Angles of squint and head postures were analyzed preoperatively, on the first postoperative day, and in the long term (median 9 weeks after the operation). Patients with Graves’ orbitopathy were excluded.ResultsFrom 2011 to 2018, the procedures on 58 eyes of 54 patients (35 females, median age 35 years (3–75)) met the inclusion criteria. Horizontal rectus muscle surgery (53 eyes) was conducted on patients with residual strabismus (13), Duane’s retraction syndrome with eso- (type I: 16)/exodeviation (type II: 2, type III: 1), 6th (7)/3rd nerve palsy (7), Möbius syndrome (2), congenital fibrosis of the extraocular muscles type 3A (CFEOM3A, TUBB3 mutation) (4), and orbital apex syndrome (1). Vertical rectus muscle surgery (5 eyes) was conducted on patients with myasthenia (1), vertical tropia after orbital floor fracture (1), CFEOM1 (2), and Parry-Romberg syndrome (1). 42 eyes had prior eye muscle surgery (1–5 procedures, median 1). Out of 45 patients with postoperative long-term data, 43 showed an angle reduction. Fifty-one percent had an angle of 10Δ (prism diopter) or less, one had a significant over-effect, and 10 had revision surgery. For the heterogeneous group of residual eso- and exotropias, the median absolute horizontal angle was reduced from 35Δ (16 to 45Δ) to 9Δ (0 to 40Δ), for Duane’s retraction syndrome from 27.5Δ (9 to 40Δ) to 7Δ (0 to 40Δ), and for sixth and third nerve palsies from 43Δ (20 to 75Δ) to 18Δ (4 to 40Δ). For 3 patients with vertical rectus muscle surgery, the median absolute vertical angle was reduced from 30Δ (20 to 45Δ) to 4Δ (1 to 22Δ). The motility range was shifted in the direction contrary to the elongated muscle in all subgroups. A considerable reduction of the excursion into the field of action of the elongated muscle had to be registered.ConclusionsStrabismus surgery with bovine pericardium introduces new surgical options for complicated revisions and for rare and complex oculomotor dysfunctions. Yet, it has to be recognized that this type of surgery aiming at maximum effects, despite preservation or restitution of the arc of contact, leads to reduction of the excursion into the field of action of the elongated muscle. Furthermore, dose finding can be difficult depending on the underlying pathology and more than one intervention might be necessary for optimal results.

The efficacy of superior oblique posterior tenectomy in the treatment of A-pattern exotropia without ocular intorsion: A retrospective study

BackgroundSuperior oblique weakening is a common method to treat A-pattern strabismus. This study aims to evaluate the surgical results of the bilateral superior oblique posterior tenectomy procedure to treat A-pattern strabismus patients who had bilateral superior oblique overaction without objective ocular intorsion.MethodsThe records of 18 consecutive patients who underwent surgery of superior oblique posterior tenectomy close to its insertion with superior oblique overaction (SOOA)-associated A-pattern strabismus between September 1, 2015 and August 31, 2018 were retrospectively reviewed. Ocular alignment, objective torsion, A-pattern and ocular motility were assessed. Ocular alignment was measured in the primary position, 25° upgaze, and 25° downgaze using the prism bar cover test, and torsion was measured using fundus photographs.ResultsA total of 18 patients (mean age: 15 years; 6 female, 12 male) underwent bilateral superior oblique posterior tenectomy and simultaneous horizontal rectus muscle surgery were included. The mean preoperative A-pattern deviation was 15 PD and the mean postoperative A-pattern deviation was 2.25 PD with a mean reduction of 12.75 PD. The mean preoperative superior oblique overaction was 2.28 and the mean postoperative superior oblique overaction was 0.43 with a mean reduction of 1.85. There was no significant correlation between the ocular torsional, vertical alignment change and the superior oblique posterior tenectomy procedure.ConclusionsSuperior oblique posterior tenectomy surgery selectively improved the A-pattern and superior oblique overaction but not affect the primary position vertical deviation, as well as the ocular torsion. It is an effective procedure to treat the mild to moderate superior oblique overaction associated A pattern strabismus without ocular intorsion.