Horizontal Muscle Surgery Research Articles

Immediate Postoperative Alignment Measurements as a Predictor of Alignment Stability in Fixed Suture Strabismus Surgery.

To evaluate the use of immediate postoperative alignment measurements as a predictor of future alignment stability in fixed suture strabismus surgery. Forty-seven patients were prospectively evaluated after undergoing horizontal or vertical rectus muscle surgery using a fixed suture technique. Alignment measurements were taken approximately 1 hour, 1 to 3 weeks, and 2 to 3 months postoperatively. A Spearman correlation coefficient was used to compare measurements from the immediate postoperative period to the 2- to 3-month postoperative period. Patients with dissociated strabismus, only oblique muscle surgery, or poor vision in one or both eyes precluding precise alternate cover test were excluded. Mean age of all patients was 46.7 years (range: 12 to 86 years). Twenty-two patients underwent surgery for exotropia: 19 for esotropia and 6 for hypertropia. Mean alignment for all surgeries was 2 prism diopters (PD) undercorrection in the immediate postoperative period, which was similar to the mean of 4.6 PD undercorrection at 2 to 3 months postoperatively. However, the Spearman correlation between the immediate postoperative and 2- to 3-month postoperative measurements was 0.18 for all surgeries, 0.03 for exotropia, 0.56 for esotropia, and 0.40 for hypertropia. The overall success rate, defined as 8 PD or less of horizontal deviation and 4 PD or less of vertical deviation, was 77% at 2 to 3 months postoperatively. The relationship between immediate postoperative alignment and future alignment stability in fixed suture strabismus surgery has not been previously defined. The current study demonstrated that although the surgical success rate was reasonably good, poor correlation occurred between the alignment immediately postoperatively and 2 to 3 months postoperatively. [J Pediatr Ophthalmol Strabismus. 2018;55(4):240-244.].

Adjustable suture strabismus surgery in infants and children: a 19-year experience

To evaluate the success rate of adjustable suture techniques in horizontal eye muscle surgery in children ≤15years of age over a 19-year period by a single surgeon. The medical records of all consecutive patients in this age group who underwent horizontal eye muscle surgery from 1989 through 2012 were reviewed retrospectively. Patients were divided into two groups: those in whom a nonadjustable suture technique was used and those in whom adjustable sutures were used. The following data were collected: type of strabismus, preoperative measurements, postoperative results, and reoperation rates. A total of 116 cases in the nonadjustable group and 521 cases in the adjustable group were included. In the adjustable group, adjustment was performed in 63% of the cases, because of either an under- (41%) or overcorrection (22%). The adjustment procedure was performed under topical proparacaine in 15% of cases and under intravenous propofol in 85%. For the adjustable group, 3-5minutes more per muscle intraoperatively and 15-20minutes for adjustment were required. No complications were encountered during the adjustment procedures. Early success rate, defined as alignment within 8Δ of straight at 3 to 6months' postoperative follow-up, was significantly greater in theadjustable group than in the nonadjustable group (77.7% vs 64.6% [P≤0.03]). Of the adjustable patients, 15% required reoperation compared with 21% of the nonadjustable patients. Use of adjustable sutures in horizontal eye muscle surgery in children ≤15years of age provided an improved success rate and fewer reoperations compared with nonadjustable sutures.

English

INTRODUCTION: Binocular single vision (BSV) is one of the hallmarks of the human race that has bestowed on it the supremacy in the hierarchy of the animal kingdom. BSV is accomplished by a perfect sensorimotor coordination of the two eyes both at rest and during movement. The two dimensional images of an object formed at the fovea of each eye, transmitted to the respective visual cortex are processed and perceived as three dimensional percept. This requires constant and controlled activity of the appropriate muscles to maintain fixation on the object. It also requires the accomodational mechanism to maintain clear view even as the object moves closer or farther. HISTORICAL REVIEW: Hippocrates, the father of medicine differentiated between concomitant and paralytic squint and stressed the hereditary aspects. 1743-George.L.deBuffon recommended occlusion of the normal eye to force the squinting eye to use. 1900 Worth and Black invented the amblyoscope 1914 Ettles introduced synoptophore 1978 Campbell introduced CAM treatment for stimulating the macula of the eye with eccentric fixation. AIM OF THE STUDY: To study the efficiency of transposition of the horizontal and the oblique muscle surgeries in correction A-V pattern. MATERIALS AND METHODS: In this prospective study, 25 cases A-V patterns that underwent surgery at the regional institute of ophthalmology, Chennai were studied. INCLUSION CRITERIA: 1. Primary non paralytic heterotropia with A&V pattern. 2. 2-25yrs age group with A&V pattern. EXCLUSION CRITERIA: 1. Paralytic exotropia 2. Severe Amblyopic cases 3. Restrictive syndrome 4. Cases that had undergone previous surgery 5. Cases associated with congenital anomalies. A routine ophthalmic examination and a thorough orthoptic evaluation were carried out in all the patients. The deviation at different distances and different gazes was quantitated. using the prism bar cover test. The status of binocular single vision was assessed using the synoptophore, Worth four-dot. The type of fixation as to whether it was central or eccentric was assessed. Refraction was done using atropine 1% or cyclopentolate 0.5% drops. Pre-operative orthoptic treatment was given when considered necessary. SUMMARY: Analysis of the efficiency of transposition surgery of horizontal and oblique muscle in correction A-V pattern yielded the following inferences. A-V pattern with no oblique overaction Vertical upshifting and downshifting of medial and lateral recti along with recession – resection had a favourable outcome in A-V patterns with no oblique overaction. A-V patterns with minimal oblique overaction Vertical upshifting and downshifting of horizontal recti along with recession – resection was also effective in patients with A-V patterns with minimal obliqure over action. For whom weakening of oblique muscle was not needed. A-V pattrns with severe oblique overaction Weakening of oblique muscle in A-V Patterns with severe oblique overaction along with recession – resection surgery had a favourable outcome. Improvement in visual acuity: Transposition of horizontal oblique muscle surgeries yielded an improvement in visual acuity postoperatively in both A-V patterns with and without oblique over action. Improvement of amblyopia: Transposition of horizontal and oblique muscle surgeries also yielded an improvement of vision in amblyopic cases in both A-V patterns with and without oblique over action. Gain in binocular single vision: Transposition of horizontal and oblique muscle surgeries showed gain in BSV in patients with A-V patterns with and without oblique over action. CONCLUSIONS: 1. Vertical transposition of horizontal muscle along with recession and resection was effective in A-V patterns in no oblique muscle over action. 2. Vertical transposition of horizontal muscle along with recession-resection was also effective in A-V patterns with minimal oblique muscle over action. 3. Oblique muscle weakening was not necessary in A-V patterns with minimal oblique muscle overaction. 4. Weakening of oblique muscle was effective in patients with A-V patterns with severe oblique muscle overaction along with recession – resection surgery. 5. Patients who underwent transposition of horizontal and oblique muscle surgeries for AV patterns had an improvement in visual acuity. 6. Patients who underwent transposition of horizontal and oblique muscle surgery for AV patterns also had an improvement in amblyopia. 7. Patients who underwent transposition of horizontal and oblique muscle surgery for AV patterns also had a gain in BSV.

Reoperation following strabismus surgery among Medicare beneficiaries: Associations with geographic region, academic affiliation, surgeon volume, and adjustable suture technique.

Purpose:The objective of this study was to determine the associations of strabismus surgery reoperation rates in a large national database of provider payments with geographic region, practice type and volume, and the availability of adjustable suture technique.Methods:Fee-for-service payments to providers for medicare beneficiaries having strabismus surgery between 2012 and 2015 were retrospectively analyzed to identify reoperations in the same calendar year. The adjustable-suture technique was considered to be available to the patient if the patient's surgeon billed for adjustable sutures. Predictors of reoperation in the same calendar year were determined by multivariable logistic regression.Results:Availability of the adjustable suture technique was not associated with reoperation rate in multivariable analysis among 5971 patients having horizontal muscle surgery (odds ratio, [OR] 0.86, P = 0.29), 2840 patients having vertical muscle surgery (OR 0.98, P = 0.93), or 1199 patients having surgery with scarring or restriction (OR 0.86, P = 0.61). For horizontal surgery, the reoperation rate was higher in academic practices (OR 1.67), as compared with community practices, and in the South (OR 2.85) and West (OR 1.92, all P < 0.001). The reoperation rate was unchanged with surgeons in the lowest-quartile of surgical volume. Among surgeons paid for horizontal surgery, 45% of surgeons in the Northeast, the West, or Florida coded for adjustable sutures, compared with 8% of surgeons elsewhere (P < 0.001).Conclusion:The availability of the adjustable-suture technique was not associated with reoperation rate after strabismus surgery in this large national database. Having surgery by a lower-volume surgeon was not associated with a higher reoperation rate. The reoperation rate was higher when surgery was conducted in an academic practice, or in certain regions of the country. Adjustable sutures are largely a bicoastal practice.

Effect of strabismus surgery on refractive power of the eye

Background The aim was to evaluate the refractive and corneal topographic changes occurring in the eyes after horizontal rectus muscle surgery, either unilateral recess–resect procedure or bilateral rectus muscle recession. Patients and methods A total of 31 eyes of 20 patients were included in this study. The patients underwent strabismus surgery for concomitant horizontal strabismus (exotropia). The patients were divided into two groups. Group A included nine patients (nine eyes), who were subjected to lateral rectus muscle recession and medial rectus resection in the same eye (R&R group). Group B included 11 patients (22 eyes) who were subjected to lateral rectus recession in both eyes (bilateral lateral rectus recession group). A full ophthalmic examination including cycloplegic automated refraction was carried out. Refraction and keratometry were assessed at 1–2 weeks preoperatively and 1 week, 1 month, and 3 months postoperatively. Corneal topography was performed before and 3 months after the operation. Preoperative and postoperative refraction was compared in terms of spherical equivalent (SE) and cylindrical power. Results The SE showed a transient statistically insignificant change toward the myopic side in the first week in both groups; these changes persisted for 2 months postoperatively and stabilized at the third month. However, the difference in SE from the preoperative values was statistically insignificant in both groups. Also, the changes in the refractive status that occurred when two muscles were operated in the same eye (R&R group) were greater than when only one muscle was operated. Conclusion Refractive status changed postoperatively, but this change was small and reversible.

Minimally invasive strabismus surgery versus fornix-based incision technique

Purpose The aim of the present study was to compare the minimally invasive strabismus surgery (MISS) and the Parks’ fornix-based incision technique. Patients and methods A total of 60 horizontal muscles of 50 eyes of 30 consecutive patients in need for horizontal rectus muscle surgery were included in the present study. They were divided into two groups: group A included surgeries performed with the MISS technique and group B included those performed using the fornix-based incision technique. The comparison addresses both the surgical techniques and the postoperative results, with a follow-up period of 6 months. Results The operative time was relatively longer in cases of MISS (51.79 min) compared with the fornix incision (30.71 min, P 0.05). Regarding postoperative visibility of the conjunctival signs, signs were hardly visible in 75% of small-sized incisions of MISS cases and in 100% of small-sized incisions in cases of fornix-based incision cases (P 0.05). Finally, in large-sized incisions, the MISS technique showed better results with less visibility of severe postoperative conjunctival signs (66.7%) than those of fornix-based incision (96%, P 0.05). Conclusion Each of the two techniques has its advantages. A definite superiority cannot be confirmed. However, it may be safer to use the MISS in elderly people with inelastic conjunctival tissue.

The accuracy of wide-field ultrasound biomicroscopy in localizing extraocular rectus muscle insertions in strabismus reoperations

To compare the accuracy of widefield ultrasound biomicroscopy (UBM) with mechanical intraoperative measurements of the distance between rectus muscle insertions and the corneal limbus in strabismus reoperations. Subjects with a history of horizontal rectus muscle surgery who required further surgery on horizontal rectus muscle(s) were recruited prospectively. All widefield UBM measurements were carried out under topical anesthesia using a 50 MHz linear probe without immersion cup and external caliper. The insertion angle distance was measured using the caliper tool of the UBM device; the actual muscle insertion distance from the limbus was considered to be the measured distance plus 1 mm. The distance from muscle insertion to the limbus was also measured intraoperatively. The results of UBM and surgical measurements were compared. A total of 28 subjects were recruited, and 53 horizontal muscles (30 medial rectus, and 23lateral rectus muscles) were included. The longest distance of the muscle insertion from limbus detectable on UBM was 13 mm for the medial rectus muscle and 15 mm for the lateral rectus muscle. In 38 muscles (71.7%) UBM and surgical measurements were within 1 mm of each other. Only in 1 muscle (1.9%) was the difference between measurements >2 mm (2.3mm). The intraclass correlation coefficient was 0.87, demonstrating excellent agreement between measurements. Limit of agreement analysis demonstrated better agreement between measurements of medial rectus muscles and in consecutive exotropia cases. This study demonstrated good agreement between intraoperative and widefield UBM measurements of the muscle insertion-limbus distance in our patient cohort.

Immediate postoperative alignment measurements as a predictor of alignment stability in fixed suture strabismus surgery

Purpose To evaluate the use of immediate postoperative alignment measurements as a predictor of future alignment stability in fixed suture strabismus surgery. Methods Forty-seven patients were prospectively evaluated after undergoing horizontal or vertical rectus muscle surgery using a fixed suture technique. Alignment measurements were taken approximately 1 hour, 1 to 3 weeks, and 2 to 3 months postoperatively. A Spearman correlation coefficient was used to compare measurements from the immediate postoperative period to the 2- to 3-month postoperative period. Patients with dissociated strabismus, only oblique muscle surgery, or poor vision in one or both eyes precluding precise alternate cover test were excluded. Results Mean age of all patients was 46.7 years (range: 12 to 86 years). Twenty-two patients underwent surgery for exotropia: 19 for esotropia and 6 for hypertropia. Mean alignment for all surgeries was 2 prism diopters (PD) undercorrection in the immediate postoperative period, which was similar to the mean of 4.6 PD undercorrection at 2 to 3 months postoperatively. However, the Spearman correlation between the immediate postoperative and 2- to 3-month postoperative measurements was 0.18 for all surgeries, 0.03 for exotropia, 0.56 for esotropia, and 0.40 for hypertropia. The overall success rate, defined as 8 PD or less of horizontal deviation and 4 PD or less of vertical deviation, was 77% at 2 to 3 months postoperatively. Conclusions The relationship between immediate postoperative alignment and future alignment stability in fixed suture strabismus surgery has not been previously defined. The current study demonstrated that although the surgical success rate was reasonably good, poor correlation occurred between the alignment immediately postoperatively and 2 to 3 months postoperatively. [J Pediatr Ophthalmol Strabismus. 2018;55(4):240-244.].

Anterior and nasal transposition of inferior oblique muscle in cases of superior oblique palsy

To report long-term outcome of inferior oblique anterior and nasal transposition in superior oblique palsy. The medical records of patients with superior oblique palsy who underwent inferior oblique anterior nasal transposition were reviewed retrospectively. A comprehensive ophthalmic evaluation, including prism bar cover test and measurement of torsion, was performed for all cases. One-year postoperative results were evaluated for alignment in primary gaze, contralateral gaze, and upgaze; reduction in inferior oblique overaction and changes in fundus torsion to assess long-term outcome of the procedure. A total of 12 patients were included. Three cases also underwent horizontal muscle surgery. Mean age at the time of surgery was 20.6years. The median preoperative hypertropia was 21.5Δ (range, 12Δ-36Δ), corrected to 4.5Δ (range, 2Δ-10Δ) at 12months postoperatively (P=0.002). Median inferior oblique overaction decreased from +3 (range, +1 to +4) to 0 (range, -1 to +1). Preoperative fundus extorsion was 19.2° ± 6.7°; postoperative, 0.58° ± 1.8° (P<0.001). No consecutive hypotropia or underaction in elevation was observed in 10patients; 1 patient complained of torsional diplopia in upgaze. Extorsion was eliminated and head tilt improved in all patients. Inferior oblique anterior and nasal transposition resulted in good long-term outcomes in our patients with superior oblique palsy presenting with hypertropia, inferior oblique overaction, and extorsion in primary gaze.

The effect of strabismus surgery on choroidal thickness.

To determine the effects of strabismus surgery on choroidal thickness. This was a prospective randomized study. The measurements of subfoveal and macular choroidal thickness of patients who underwent strabismus surgery were obtained by enhanced depth imaging optic coherence tomography. The patients were grouped as patients who had 1 horizontal muscle surgery (group 1), 1 oblique muscle surgery (group 2), 2 horizontal muscle surgeries (group 3), or 1 horizontal and 1 oblique muscle surgery (group 4). Choroidal thickness of the patients was measured preoperatively and on the postoperative first day, second week, first month, and third month. Choroidal thickness was measured at subfoveal area (S) and at the nasal (N1, N2) and temporal (T1, T2) fovea with 500-μm intervals. The average age of the 37 patients was 15.59 ± 13.84 years. In preoperative and postoperative first day comparison, a decrease in choroidal thickness was found in all areas in group 1. In group 2, a significant decrease was found in N2, N1, and S values. In group 3, a significant decrease was found in N2, N1, and T2 values. In group 4, a significant decrease was found in N1 value. The second week comparison of all groups showed significant postoperative decrease in choroidal thickness in all areas. On the postoperative first month, a significant decrease in choroidal thickness was found only in the subfoveal area of group 1 and the N1 area of group 2. At the postoperative third month, there was no change in any group. Strabismus surgery causes a decrease in choroidal thickness in the early postoperative period.

Clinical Features and Surgical Outcome of Triad Exotropia.

To describe the clinical features and surgical outcome of A-pattern exotropia combined with dissociated vertical deviation and superior oblique overaction. The medical records of patients with A-pattern exotropia combined with dissociated vertical deviation and superior oblique overaction who underwent horizontal muscle surgery alone or in combination with superior oblique muscle weakening surgery were retrospectively reviewed. The patients were divided into two groups according to their surgery: the horizontal muscle surgery alone group and the horizontal muscle surgery with bilateral superior oblique weakening surgery (combined surgery) group. The preoperative clinical features and postoperative surgical outcomes at the patients' final follow-up visits were analyzed. A total of 40 patients were included. The mean age at diagnosis was 5.5 ± 4.6 years. Amblyopia and latent nystagmus were observed in 18 (45%) and 10 (25%) patients, respectively. Six (15%) patients were associated with delayed development and hemiplegia. The mean angle of exodeviation was 27.7 ± 11.2 and 28.5 ± 10.9 prism diopters (PD) for distance and near, respectively. The mean degree of superior oblique overaction was 1.9 ± 1.1 and asymmetrical dissociated vertical deviation was observed in 24 (60%) patients. At the final follow-up visit, the horizontal angle of deviation was not significantly different between the groups. The success rates were 57.1% and 80% in the horizontal muscle surgery alone and combined surgery groups, respectively. These differences were statistically significant (P = .04). Amblyopia was common and the prognosis of binocularity was poor in triad exotropia. Some patients had neurological deficits. The surgical success rate in this study was variable, ranging from 57.1% to 80%. [J Pediatr Ophthalmol Strabismus. 2017;54(6):363-368.].

Resolution of hypertropia with correction of consecutive horizontal deviation

BackgroundTo study the resolution of hypertropia in patients who undergo horizontal deviation surgery for consecutive esotropia or consecutive exotropia. MethodsWe retrospectively reviewed the records of 23 patients with consecutive esotropia or exotropia who had concomitant vertical tropia. All patients had had surgery for horizontal deviation that required further surgery to correct consecutive horizontal strabismus and had a minimum of six months of postoperative follow-up. All patients were noted to have vertical deviation greater than 5 prism diopters (PD) in primary position on preoperative examination. Patients underwent corrective surgery for horizontal strabismus without surgical manipulation of the vertical extraocular muscles. The exclusion criteria were coexisting oblique muscle dysfunction, manifest or latent dissociated vertical deviation, and extraocular muscle palsy. ResultsThe mean preoperative vertical deviations were 7.6 ± 2.3 PD for distance and 7.3 ± 2.3 PD for near. All patients had resolution of vertical deviation in all fields of gaze despite surgical correction only being made to horizontal extraocular muscles. No patients had measureable vertical tropia during six months of follow-up. ConclusionWe propose that measureable hypertropia unrelated to oblique muscle dysfunction, dissociated vertical deviation, or paretic/mechanical muscle that coincides with consecutive horizontal deviation can be resolved with horizontal muscle surgery alone. Therefore, it may not be necessary to perform vertical surgery to correct coincident vertical deviation in patients with consecutive horizontal deviation. More research is needed in the form of prospective clinical trials to determine whether vertical surgery has any utility for these patients.

A Valid Indication and the Effect of Bilateral Inferior Oblique Transposition on Recurrent or Consecutive Horizontal Deviation in Infantile Strabismus.

PurposeTo evaluate the effects of bilateral inferior oblique transposition (BIOT) on horizontal deviation from primary position among patients with bilateral dissociated vertical deviation (DVD) associated with inferior oblique overaction (IOOA) in infantile strabismus.MethodsRetrospective chart review was conducted among 19 patients with infantile strabismus. All patients had DVD and IOOA with consecutive or recurrent horizontal deviation and underwent modified BIOT surgery. Patients were divided into three subgroups: patients who underwent BIOT (BIOT group, n = 9) alone, BIOT with medial rectus recession or lateral rectus resection simultaneously (ET BIOT group, n = 6), or BIOT with lateral rectus recession or medial rectus resection simultaneously (XT BIOT group, n = 4). Postoperative angle of horizontal deviation (prism diopter, PD) and corrected magnitude of horizontal deviation (PD) at final visit after surgery were analyzed in each group.ResultsThe mean age was 55.11 ± 21.05 months (range, 32 to 115). The mean follow-up period was 8.68 ± 2.87 months (range, 6 to 18). Preoperative horizontal deviation was 4.23 ± 5.99 PD (range, 0 to 16) in BIOT, −17.33 ± 6.76 PD (range, −30 to −10) in ET BIOT, and 17.50 ± 2.52 PD (range, 14 to 20) in XT BIOT. Esodeviation is represented by negative values. DVD and IOOA were reduced less than +1 in all patients. The corrected amount of horizontal deviation was 3.56 ± 5.18 PD (range, 0 to 16) in BIOT surgery alone and larger in XT BIOT (18.50 ± 3.41 PD) than in ET BIOT (12.33 ± 5.57 PD, p = 0.004).ConclusionsMinimal exodeviation was corrected by BIOT alone. In addition, secondary eso- or exodeviation at great magnitudes should be corrected with proper horizontal muscle surgery along with BIOT.

The effect of surgical intervention for dissociated vertical deviation (DVD) alone on concurrent horizontal strabismus

The purpose of this study is to determine whether DVD surgery in patients with concomitant horizontal strabismus can improve control of the latter, avoiding horizontal muscle surgery.

A comparative study of adjustable and non-adjustable sutures in primary horizontal muscle surgery in children

PurposeTo compare the results of using adjustable and non-adjustable sutures in primary horizontal strabismus surgeries in children.MethodsThis randomized control trial included 60 cases of primary horizontal deviation. The adjustable suture (AS) group included 30 patients, and the non-adjustable suture (NAS) group included 30 patients. The follow-up period was at least 6 months. A successful motor outcome was defined as orthophoria or a horizontal tropia of 8 PD or less at both near and far distances. The success rate and ocular drift were recorded and analysed.ResultsThe mean age in the AS group was 3.48±2.37 years at the time of surgery. The mean age in the NAS group was 3.55±2.64 years at the time of surgery. The success rate at the end of 6 months was 86.67% in the AS group and 73.33% in the NAS group (P=0.197). In exotropic patients, there was a mean undercorrection drift of 2.86 PD in the AS group and a mean undercorrection drift of 2.17 PD in the NAS group. In esotropic patients, there was a mean undercorrection drift of 0.26 PD in the AS group and a mean undercorrection drift of 1.83 PD in the NAS group.ConclusionThere was no significant difference between the groups. However, the success rate was clinically higher in the AS group than in the NAS group.

Intermittent exotropia with a positive Bielschowsky head-tilt test.

To investigate the clinical features of patients with intermittent exotropia (IXT) with and without positive Bielschowsky head-tilt test (BHTT), but without superior oblique palsy. We retrospectively reviewed the charts of 118 patients with IXT. Patients were divided into two groups according to positive or negative BHTT. Associated risk factors for positive BHTT in patients with IXT were analysed. The changes in the BHTT result after surgery were also analysed. Fifty patients showed a positive BHTT, and 68 patients showed a negative BHTT. There were significant differences between the groups with regard to the elapsed time from the onset of IXT, the angle of distance exodeviation, inferior oblique muscle overaction, vertical deviation at the primary position, suppression and stereoacuity (all for p<0.05). Risk factors for a positive BHTT among patients with IXT were the elapsed period since the onset of IXT (OR, 1.034; 95% CI 1.008 to 1.061, p=0.011), angle of distance exodeviation (OR, 1.087; 95% CI 1.015 to 1.165, p=0.017) and near stereoacuity (OR, 1.006; 95% CI 1.001 to 1.011, p=0.029). Horizontal muscle surgery alone, without cyclovertical muscle surgery, resulted in a significant decrease in the number of patients with positive BHTT (p<0.01). A positive BHTT was seen in patients with IXT with larger angle exodeviations, longer elapsed time periods since the onset of IXT and worse stereoacuity. The positive BHTT could be eliminated using horizontal muscle surgery only, without complementary inferior oblique muscle weakening surgery.

Strabismus surgery among Medicare beneficiaries: imputed rates of reoperation in the same calendar year.

To compare strabismus surgery reoperation rates in a large national database of provider payments when the adjustable-suture technique was available and not available. Fee-for-service payments to Medicare providers for horizontal (CPT 67311) and vertical (CPT 67314) strabismus surgery in 2012 were analyzed to identify payments for reoperations in the same calendar year. The adjustable-suture technique was considered to be available to the patient if the patient's surgeon billed for adjustable sutures during the year. We determined the association of reoperation with the availability of the adjustable-suture technique and with surgeon volume. Patients having horizontal muscle surgery had a rate of reoperation in 2012 of 4.1% (15 of 364 patients) when the adjustable technique was available, compared with 7.1% (77 of 1,082 patients) when the adjustable technique was not available (P = 0.047). Patients having vertical muscle surgery had a rate of reoperation in 2012 of 4.1% (8 of 196 patients) when the adjustable technique was available, compared with 8.3% (38 of 458 patients) when the adjustable technique was not available (P = 0.07). Having surgery in a high-volume surgical practice was not reliably associated with reoperation rates. For patients having strabismus surgery, the availability of the adjustable-suture technique was associated with a lower reoperation rate in this large national database (compared with patients for whom the adjustable technique was not available). The difference was statistically significantly different from zero for horizontal muscle surgery but not for vertical muscle surgery.

Planning Strabismus Surgery: How to Avoid Pitfalls and Complications

Background and PurposeGood surgical results following strabismus surgery depend on several factors. In this article, detailed steps for planning strabismus surgery will be reviewed for basic horizontal strabismus surgery, vertical, and oblique muscle surgeries. The thought process behind each case will be presented to help in selecting the best surgical approach to optimize postoperative results.Patients and MethodThe surgical planning for strabismus will be developed with clinical examples from easy cases to more complex ones. Preoperative pictures of the ocular alignment are an integral part of planning surgery and help in documenting the strabismus before and after surgery.ResultsThree cases of strabismus cases will be reviewed with several key factors for planning surgery, including visual acuity, refractive error, potential for stereovision, and risk of postoperative diplopia. The most important factor is accurate orthoptic measurements. The surgical planning for each patient is detailed along with preoperative pictures.ConclusionStrabismus surgery results can be improved by careful preoperative planning. The surgeon has the ability to discern potential pitfalls that can alter the surgical outcome. Surgical planning allows a dedicated time of reflection before surgery, foreseeing potential problems, and avoiding them during the surgery.

Predictability of horizontal versus vertical muscle surgery outcomes in thyroid eye disease.

Surgical repair of vertical muscles in thyroid eye disease (TED) is believed to yield more unpredictable results than horizontal muscle surgery. The purpose of this study is to determine if the short-term outcomes for strabismus surgery in TED are equally predictable for horizontal and vertical muscle surgery. We retrospectively reviewed the charts of 27 consecutive patients who underwent strabismus surgery for TED from a single surgeon's practice. Eligibility for inclusion in the study included biochemically stable thyroid disease for at least a year and stable orthoptic measurements for at least 6months prior to surgery. Nine patients had surgery only on vertical rectus muscles, three only on horizontal, and fifteen on both vertical and horizontal rectus muscles. Mean follow-up was 2.4±5.2months. In primary gaze at 6m, a mean horizontal deviation of 16.6±22.3 PD, and a mean vertical deviation of 19.7±14.1 PD were measured pre-operatively. Post-operatively, this measured 2.3±8.4 PD horizontally and 2.1±7.8 PD vertically (p=0.933). There was no statistically significant difference between post-operative horizontal and vertical deviations in elevation, depression, adduction, and abduction. Nine patients required reoperation to attain satisfactory ocular alignment; seven of these cases involved repeat surgery on vertical muscles, while two cases required operation on both horizontal and vertical muscles. Results suggest that surgical outcomes of both horizontal and vertical muscle surgery are equally predictable in stable TED; however, reoperation rates were higher for vertical muscles compared to horizontal muscles.

Effect of Horizontal Strabismus Surgery on the Refractive Status

Purpose: To evaluate the effects of horizontal strabismus surgery on the refractive and astigmatic status of eyes following horizontal muscle surgery using double-angle vector analysis.Materials and Methods: This was a retrospective analysis of 137 patients (250 eyes) conducted between February 1997 and October 2010 in patients who had unilateral or bilateral recession or monocular recession and/or underwent resection of horizontal muscles by a single surgeon. Refraction data were obtained at 1–2 weeks preoperative and at 4–6 weeks and 4–6 months postoperative. Surgically induced refractive changes were calculated using double-angle vector analysis.Results: The mean change in the spherical equivalent (SE) of the refraction was 0.23 ± 0.78 D for surgically induced refractive changes at 4–6 weeks postoperative (SIRC1; p < 0.0001) and 0.14 ± 0.85 D (p = 0.018) for surgically induced refractive changes at 4–6 months postoperative (SIRC2), indicating a small shift in the myopic direction with regression at 4–6 months. The mean amplitudes of the induced cylinders were 0.072 ± 1.22 D (p = 0.262) in SIRC1 and 0.20 ± 1.14 D (p = 0.012) in SIRC2, and the mean axis of the induced plus cylinder was 21.74° in SIRC1, indicating a small shift in the with-the-rule direction, but no statistically significant difference from zero (p = 0.331). The changes in the surgically induced refraction over time (SIRC d), ie, 0.05 ± 0.64 in SE (p = 0.255) and 0.09 ± 0.65 in the cylinder (p = 0.049), were stable. There was no significant correlation between the amounts of horizontal rectus muscle recession and/or resection and the cylinder power of individual induced astigmatism at 4–6 weeks after surgery (p = 0.266) and the myopic shift (p = 0.345). Moreover, there were no significant correlations between the ages of the patients and the spherical equivalent for SIRC1 (p = 0.858) and the induced cylinder for SIRC1 (p = 0.750).Conclusion: Horizontal rectus muscle surgery tended to induce a transient, statistically significant change in the spherical equivalent of refraction, with a myopic shift that was clinically not important. Our findings did not strongly support that the astigmatism induced changes. There was no correlation between the amount of recession and/or resection and the amount of induced refractive error.