Inferior Oblique Weakening Research Articles

Effect of graded partial inferior rectus muscle tenotomy in treatment for superior oblique paralysis.

To evaluate the surgical outcomes for patients with superior oblique paralysis (SOP) who underwent the inferior oblique weakening and the graded partial inferior rectus muscle tenotomy in the contralateral eye. Medical records were retrospectively reviewed for those SOP patients who had hyperdeviation of 4△ -20△ in the primary position and 8△ -25△ in the downgaze position. Patients were subdivided into three subgroups according to their vertical deviation angle in the downgaze position. They underwent an ipsilateral inferior oblique muscle recession and a graded partial tenotomy of the contralateral inferior rectus muscle. The vertical deviation angles, abnormal head position, and fundus torsion were compared statistically before and after operations. All patients were followed up at least 1 year. Forty-seven patients were included in this study. The mean follow-up period was 17.2 months after surgery (ranging from 12 to 28 months). The vertical deviation angle was averaged preoperatively to 7.74△ ± 3.23△ in the primary position and 15.30△ ± 5.92△ in the downgaze position and reduced postoperatively to 0.85△ ± 1.15△ in the primary position and 1.53△± 1.49△ in the downgaze position (P < 0.001). All patients had an abnormal head position preoperatively and had improved significantly postoperatively. Fundus extorsion had been improved significantly postoperatively. The surgical procedure of IO weakening combined with contralateral graded partial inferior rectus muscle tenotomy is a successful intervention for the correction of small deviation in primary position of SOP.

The effects of refractive status on the outcomes of strabismus surgery in patients with esotropia

BackgroundThe success of the strabismus surgery can hinge on several factors. One of these factors is refractive condition like hyperopia or myopia. Our study seeks to evaluate the surgical outcomes in patients with esotropia and myopia.MethodsThis case-control study encompassed all surgical cases of esotropia at Torfe and Negah Hospital between 2016 and 2021, which satisfied our specified inclusion criteria. The initial variables from electronic medical records were collected, including demographic, clinical, and surgery-related factors. At the final follow-up appointment, the level of eye deviation, both at distance and near, was recorded. We considered the operation a “success” for patients with a post-surgery distance eye deviation of 10(Pd) or less. Patients with greater deviation were classified as surgery failure. Statistical analyses were executed using SPSS software (version 16.0), and a P-value less than 0.05 was considered significant.ResultsOf the 194 patients evaluated, 112 were incorporated into the study. Surgical failure was observed in 14.29% of myopic patients, 29.79% of hyperopic patients, and 31.82% of emmetropic patients. The myopia group displayed a 0.19 odd ratio for surgical failure compared to the combined hyperopia and emmetropia groups, not statistically significant (OR: 0.19, CI 95%: 0.03–1.02). Additionally, patients diagnosed with Lateral Rectus Under-action were found to be 6.85 times more likely to experience surgery failure(OR: 6.85, CI 95%: 1.52–30.94). An elevated risk of surgical failure was also identified in patients who underwent Inferior Oblique Weakening procedure, indicated by a 3.77-fold increase in the odds ratio for failure(OR: 3.77, CI 95%: 1.08–13.17).ConclusionIn our study, despite numerical disparities, there was no statistical difference among the success rates of all esotropia patients with different refractive errors. The patients with LRUA or IOOA showed lower success rates. Myopic patients had higher post-op overcorrection with lower reoperation rates compared to hyperopic or emmetropic patients.

Fundus torsion following inferior oblique muscle weakening

PurposeTo determine the postoperative fundus torsion following surgical inferior oblique (IO) weakening in patients with inferior oblique overaction (IOOA). MethodsIn this interventional case series, 37 patients with IOOA ≥ +1 and reliable preoperative fundus photographs were included. IO weakening was accomplished through myectomy or anterior transposition. Fundus photography was repeated at 3 months’ follow-up. The primary outcome was change of disk foveal angle (DFA), measured as the angle between the line connecting the center of the fovea and optic disk and horizontal. Success or normal fundus torsion was defined as a postoperative angle of 0° to 8° of extorsion. Residual extorsion was defined as postoperative extorsion of > 8°. Postoperative intorsion was defined as any amount of induced intorsion. ResultsMean age of patients (56% females) was 6.46 ± 6.79 years. At follow-up at least 3 months after surgery, the mean change of DFA was 7.79 ± 6.24° of reduction of extorsion after IO myectomy (P < 0.001) and 6.05 ± 6.07° after IO anterior transposition (P = 0.005). Normal fundus torsion was achieved in 50% of patients after myectomy and 36.4% of patients after anterior transposition. Residual extorsion was observed in 49% of patients; induced intorsion in 5%. ConclusionsUsing objective measurement of fundus photographs, fundus extorsion was decreased in 94.7% of patients after myectomy or anterior transposition.

Evaluation of change in objective cyclotorsion after various inferior oblique–weakening procedures

PurposeTo study the effect of four types of inferior oblique–weakening procedures on ocular torsion: inferior oblique recession (IOR), recession and antero-positioning (RAP), anterior transposition as practiced by Elliot and Nankin (EN), and anterior and nasal transposition (ANT). MethodsThe medical records of 72 consecutive patients >10 years of age undergoing inferior oblique weakening for primary or secondary inferior oblique overaction (IOOA) with or without horizontal rectus surgery were reviewed retrospectively. The 106 included eyes were assigned to one of the four groups according to the type of inferior oblique–weakening procedure. The severity of IOOA and the amount of V pattern guided the choice of procedure. IOOA, disk-fovea angle (DFA), and the amount of V pattern were recorded preoperatively. Measurements were repeated postoperatively at 1 week, 4 weeks, and 3 months. Change in the DFA was used to study the change in objective cyclotorsion in all four groups. ResultsA significant incyclotorsional shift was seen in all four groups at postoperative 3 months. The mean reduction in excyclotorsion 3 months postoperatively was 3.65° ± 4.84° for IOR, 5.31° ± 4.64° for RAP, 6.10° ± 3.89° for EN, and 16.62° ± 8.72° ANT; it was significantly higher in the ANT group compared with the other three groups. Reduction in DFA was also correlated with preoperative DFA overall, and for all procedures except IOR (P ≤ 0.005). ConclusionsAll four inferior oblique–weakening procedures reduced excyclotorsion; the largest reductions in our study were seen in cases treated using ANT of the inferior oblique.

Factors associated with changes in horizontal deviation after inferior oblique weakening surgery.

To identify the factors affecting postoperative horizontal deviation following isolated inferior oblique (IO) weakening surgery. The medical records of patients who had undergone isolated IO weakening surgery between February 2010 and September 2021, with a minimum follow-up period of 6 months, were retrospectively reviewed. Patients were divided into two groups, eso-shift, and non-eso-shift, based on the change in horizontal deviation at postoperative 6 months. Eso-shift or exo-shift was defined as a change of 2Δ or more. A total of 77 patients were included. Among them, 49 patients (63.6%) showed changes in horizontal deviation: 37 (48.0%) eso-shift, 12 (15.6%) exo-shift. Twenty-eight patients (36.4%) showed no change in alignment. The eso-shift group showed the following characteristics compared to the non-eso-shift group: older age (P < 0.001), higher proportion of patients with preoperative exo-deviation (P < 0.001), and greater preoperative hypertropia in primary gaze (P < 0.001), down gaze (P = 0.031), ipsilateral gaze (P < 0.001), and ipsilateral head tilt (P = 0.002). Regarding the postoperative changes in horizontal deviation based on prior horizontal strabismus, patients with preoperative exo-deviation showed a statistically significant eso-shift. The patients with prior eso-deviation tended toward exo-shift, while those without prior horizontal deviation rarely changed. Changes in postoperative horizontal deviation are associated with preoperative horizontal and vertical deviation, which might result from changes in the rectus muscle due to oblique muscle dysfunction. Also, this study suggests that isolated IO weakening surgery could effectively correct small-angle horizontal deviation in patients with inferior oblique overaction (IOOA) and horizontal strabismus.

Surgical management of superior oblique palsy with coexisting exotropia

To analyze the surgical results of patients treated for superior oblique palsy with coexisting exotropia. The medical records of patients with superior oblique palsy and exotropia who underwent inferior oblique weakening and simultaneous lateral rectus recession by a single surgeon from 1996 to 2022 were reviewed retrospectively. Demographics, pre- and postoperative vertical and horizontal deviation, and presence of diplopia were recorded. Surgical success was defined as horizontal deviation <10Δ and vertical deviation ≤4Δ without overcorrection or diplopia. The decision to operate for the horizontal deviation was made based on fusion in free space when the vertical deviation was offset with a prism. A total of 27 patients were included. Mean age was 26.1 ± 22 years (range, 26 months to 78 years). Preoperatively, mean vertical deviation was 15.2Δ ± 7.5Δ (range, 4Δ-30Δ); mean exodeviation, 17Δ ± 5.5Δ (range, 10Δ-35Δ). Of the 27 patients, 25 underwent unilateral and 2 underwent bilateral lateral rectus recession, according to the magnitude of the horizontal deviation. Mean follow-up was 3 ± 3.8 months (range, 2 weeks to 17 months). Postoperative mean vertical alignment was 3.0 ± 5.9, and horizontal alignment was 3.4Δ ± 5.2Δ (esotropia of 7Δ to exotropia of 12Δ; P < 0.0001). Nineteen patients (70%) had a successful result; 2 patients had residual exotropia of >10Δ, 2 had vertical overcorrection (range, 3Δ-4Δ), and 6 had residual vertical deviation ≥4Δ (range, 5Δ-20Δ). None had secondary esotropia >10Δ. Horizontal deviation was corrected successfully with no consecutive esotropia in 25 patients. In our study cohort, patients with superior oblique palsy and exotropia in whom fusion required both horizontal and vertical prism correction had a high likelihood of successful horizontal alignment after lateral rectus weakening in combination with inferior oblique surgery.

Comparison of the results of the modified and classical bi-medial hang-back recession in infantile esotropia.

Bi-medial rectus recession, which can also be performed using a hang-back technique, is one of the surgical treatment options for infantile esotropia (IE). This study has modified the surgical approach, with outcomes compared to the traditional hang-back technique. The bi-medial recession was performed with a modified hang-back technique in 120IE patients and with a traditional hang-back technique in 88 cases. Surgical outcomes were reviewed and compared retrospectively. The patients in the two groups were compared in terms of surgery time, inferior oblique weakening surgery, and the presence of refractive error. The differences between pre-operative and postoperative first-month, sixth-month, and first-year degrees were statistically significant (p < 0.001). This modified novel technique aims to avoid unwanted muscle movement in the horizontal and vertical axes and a gap in the middle of the recessed muscle, as seen in the traditional hang-back technique. Further, the modified technique resulted in less over- and under-correction as well as alphabetic pattern deviation.

Superior oblique tuck-effectiveness in reducing vertical deviations when performed as a primary versus secondary procedure in superior oblique paresis.

To quantify the effectiveness of superior oblique tuck (SOT) surgery in patients with a hyperdeviation secondary to superior oblique paresis (SOP). Surgical outcomes were compared in patients undergoing SOT surgery as a primary procedure with those who had previously undergone ipsilateral inferior oblique weakening surgery. This retrospective study assessed surgical outcomes from all patients undergoing SOT surgery for SOP between 2012 and 2021 across 2 hospitals. The effectiveness of SOT surgery in reducing the hyperdeviation was assessed in the primary position (PP) and in contralateral elevation and depression. Results were compared between those undergoing primary SOT surgery with those who had previously undergone ipsilateral inferior oblique weakening surgery. A total of 60 SOT procedures were performed between 2012 and 2021. 7 were removed due to incomplete data. The remaining 53 cases experienced a mean reduction in hyperdeviation of 6.5 prism dioptres (PD), 6.7PD and 12.0PD in the PP, contralateral elevation and contralateral depression respectively. In eyes with previous IO weakening, the reduction of hyperdeviation was larger than in those eyes with no previous IO weakening surgery, with mean reductions of 8.0PD vs 5.2PD, 7.4PD vs 6.2PD and 12.4PD vs 11.6PD in the PP, contralateral elevation and contralateral depression respectively. SOT surgery is a safe and effective procedure with high patient satisfaction and resolution of symptoms in those patients with troublesome diplopia in downgaze secondary to SOP. This is true in both unoperated eyes and in those who have previously undergone inferior oblique weakening surgery.

Comparison of horizontal muscle transposition and Inferior oblique weakening combined with horizontal surgery in V-pattern exotropia.

The objective of this study was to compare the effects of horizontal muscle transposition and inferior oblique weakening combined with horizontal surgery performed for V-pattern exotropia (XT) and to determine the most successful approach. In our retrospective study, 52 patients who underwent horizontal surgery due to V-pattern XT and were followed up for at least 6 months were divided into two groups. Group 1 (n = 26) consisted of patients who underwent vertical transposition of the rectus muscles combined with horizontal surgery, and group 2 (n = 26) consisted of patients who underwent inferior oblique weakening combined with horizontal surgery. The two groups were compared before and after surgery in terms of visual acuity, refractive errors, deviation angles, pattern strabismus, fusion, stereopsis, over/under correction and surgical success. There was no difference between the two groups in terms of age, follow-up period, visual acuity, refractive errors, fusion or stereopsis. The amount of horizontal deviation was smaller in group 2 at the 1-6-month follow-ups. There was no difference between the two groups in terms of pattern collapse; however, the amount of pattern postoperatively was lower in group 2. The two groups were similar in terms of overcorrection; however, the undercorrection rate was higher in group 1. The surgical success rate was higher in group 2. Inferior oblique weakening combined with horizontal surgery due to V-pattern XT was found to be superior to vertical transposition of the horizontal muscles in terms of surgical success and the amount of pattern postoperatively.

Effect of Trainee Participation on Operative Times in Strabismus Surgery

Abstract Introduction This study aimed to describe the difference in operative time during strabismus surgery in the presence and absence of a trainee with the operating physician. Methods This is a retrospective chart review of pediatric patients who underwent strabismus surgery by three surgeons from January 2016 through September 2019. Electronic medical records were reviewed and noted for operative times as well as the presence or absence of a trainee (postgraduate year [PGY]-3 ophthalmology resident, PGY-5 pediatric ophthalmology fellow, or both). Results The average time needed for a two-horizontal muscle recession by all the three surgeons in the absence of a trainee averaged at 35.7 minutes (range: 24–48). This is increased by 34% in the presence of a trainee with an average of 47.88 minutes (range: 20–81) with a p-value &lt; 0.001. Similar comparisons were performed for a two-horizontal muscle recession in addition to bilateral inferior oblique weakening procedures for two surgeons. On average, in the absence of a trainee, this required an average of 61.9 minutes for completion with an increase of 31.8% with the participation of a trainee requiring 81.56 minutes. Discussion The presence of trainees, whether residents or fellows, is a crucial component of medical education and training. It is important for their learning and helps develop strong future surgeons. However, this may increase surgical procedure times and affect the efficiency of the primary surgeon. This has important implications for surgical scheduling, surgical time utilization, and surgical productivity of those involved in trainee education. Conclusion The presence of a trainee with a primary surgeon, although crucial to surgical training, may result in significant prolongation of strabismus surgical times.

The Role of Hypertropia in the Surgical Management of Bilateral Inferior Oblique Muscle Overaction

ABSTRACT Purpose Inferior oblique muscle overaction (IOOA) is an ocular motility anomaly consisting of overelevation in adduction, often associated with ipsilateral hypertropia. The weakening procedure of IO muscle is the most widely used procedure in IOOA. Usually, surgical planning is based on the degree of overaction of the IO muscle. Materials and Methods We have retrospectively analyzed patients with bilateral IOOA with and without hypertropia in primary position, who underwent a bilateral IO weakening procedure. Both the amount of IOOA and the presence of a hypertropia in primary position were taken into consideration for the surgical plan. Results Nineteen patients met the entry criteria for this study. In 12 patients, a hypertropia in primary position was present at baseline, and it was significantly lower after the asymmetrical IO weakening: 11 had an asymmetric IOOA at baseline, and one had symmetric IOOA. None of the remaining seven patients had a vertical deviation in primary position before surgery, despite having asymmetric IOOA. None of them developed a hypertropia in primary position after symmetric IO weakening. Conclusions Our findings outline the utility of considering both the presence of a vertical deviation in primary position and the magnitude of IOOA in this set of patients. Asymmetric inferior oblique weakening procedure is effective in treating a hypertropia in the primary position and bilateral IOOA.

Effect of unilateral inferior oblique weakening on fundus torsion in bilateral eyes of children with congenital superior oblique palsy.

To study the change of torsion in both eyes after unilateral inferior oblique (IO) weakening on children with congenital superior oblique palsy (SOP). This retrospective study enrolled all patients diagnosed with unilateral congenital superior oblique palsy (UCSOP) accompanied by inferior oblique overaction (IOOA). A total of 120 eyes of 60 patients were divided into group 1 (more extorted paretic eye) and group 2 (more extorted nonparetic eye). The degree of fundus torsion was evaluated before and 1mo after the IO weakening procedure. The torsion of the fundus was recorded by measuring the disk-foveal angle (DFA) using fundus photography. Group 1 included 26 cases and group 2 included 34 cases, thus the rate of extorsion was insignificantly higher in the nonparetic eye (P=0.10). The preoperative DFA in the paretic and nonparetic eyes was 13.21±5.95, 7.97±4.25 in group 1, and 4.65±3.79, 13.16±5.35 in group 2 (both P<0.001). The postoperative DFA in the paretic and nonparetic eyes was 8.57±4.87, 7.32±4.27 in group 1 (P=0.24), and 3.85±6.00 and 9.94±5.45 in group 2 (P<0.001). The amount of postoperative reduction of the DFA in the paretic and nonparetic eyes was 4.64±3.90, 0.65±0.76 in group 1 (P=0.002), and 0.80±0.81, 3.21±5.50 in group 2 (P=0.01). The difference in the amount of reduction of DFA in the more extorted eye in group 1 (paretic eye) vs group 2 (nonparetic eye) was insignificant (P=0.30). Excyclotorsion in the nonparetic eye has a similar probability in the paretic eye in UCSOP children, and weakening of the ipsilateral IO has a more obvious effect on the decrement of extorsion in the more extorted eye regardless of which eye is paretic.

Self-grading effect of inferior oblique myectomy and recession

To evaluate the outcomes of inferior oblique (IO) weakening surgery, whether recession or myectomy, and to assess the dose-response relationship and correlation with angle of preoperative hypertropia. The medical records of all patients with vertical deviation in primary gaze who underwent unilateral IO-weakening surgery, either recession or myectomy, at Boston Children's Hospital over an 8-year period with a minimum postoperative follow-up of 1month were reviewed retrospectively. Outcome measures were effect of IO weakening surgery on vertical deviation in primary gaze and its correlation with the preoperative angle of hyperdeviation. Secondary outcomes included resolution of abnormal head posture, reduction of ocular torsion, and postoperative under- and overcorrection. A total of 94 patients were identified (mean age at surgery, 29.3±19.8years; range, 1-69). The mean postoperative follow-up period was 17.2±15months. IO recession was performed in 30 patients; IO myectomy, in 64. Surgical success in primary position was achieved in 72 patients (77%), with resolution of anomalous preoperative head posture in 93%. The mean effect on alignment in primary position was 11.3Δ ± 6.8Δ. The response to IO-weakening surgery was strongly correlated with the preoperative hyperdeviation for both recession (R2=0.53) and myectomy (R2=0.87). As with other types of strabismus surgery, IO weakening has a "self-grading" contribution, in which the surgical effect strongly correlates with the magnitude of preoperative deviation. A large range of vertical misalignment can be corrected with the same surgical approach.

Surgical outcomes of three different weakening procedures of inferior oblique muscle in the treatment of unilateral superior oblique palsy

BackgroundTo compare surgical outcomes and complications of three inferior oblique weakening procedures; Inferior Oblique Myectomy (IOM), Inferior Oblique combined Resection-Anterior Transposition (IORAT) and Inferior Oblique Anterior Transposition (IOAT) in the management of unilateral Superior Oblique (SO) palsy.MethodsRetrospective review of medical records of all patients with unilateral SO palsy who underwent one of the aforementioned IO weakening procedures at Benha University hospital was performed. Patients were excluded if surgery was bilateral or combined with other vertical muscle surgery. Primary outcome parameters were improvement of Hypertropia (HT) in primary gaze, side gazes, on alternate head turn, Inferior Oblique Overaction (IOOA), Superior Oblique Underaction (SOUA), correction of head tilt and postoperative complications.ResultsThe review reveals a total of 65 patients with unilateral SO palsy; 54 congenital and 11 acquired, who met the study criteria and were classified into 3 groups; IOM group (24cases), IORAT group (19cases) and IOAT group (22cases). Compared with IOM, both IORAT and IOAT induced significant correction of HT in primary position, ipsilateral gaze, contralateral head tilt and IOOA. IORAT was significantly more effective than IOAT in correction of HT in ipsilateral gaze and contralateral head tilt while there was no statistical difference between the three groups in correction of HT in ipsilateral gaze, contralateral head tilt and SOUA. Postoperative Anti-elevation was significantly recorded following IORAT (6 cases, 31%) than IOAT (3 cases, 13%) and IOM (one cases, 4%).ConclusionsThe IORAT and IOAT were more superior to IOM in correction of IOOA and HT in the primary position and some other gaze positions. However, superiority of IORAT over the other two procedures should be weighed against its significant association with postoperative underaction of IO muscle and anti-elevation syndrome.

Comparison of Techniques for Correction of Chin-down Vertical Abnormal Head Position Associated with Infantile Nystagmus Syndrome

We evaluated the relative effectiveness of combined recession-resection of vertical rectus muscles versus superior rectus recession with inferior oblique weakening for patients who underwent surgical correction of chin-down abnormal head position (AHP) associated with infantile nystagmus syndrome (INS). Retrospective interventional case series. This is a review of 22 patients who underwent surgical correction of chin-down vertical AHP associated with INS at an academic institution. The primary outcome was collapse of AHP. Unfavorable outcomes included repeat surgery and induced strabismus, in addition to failure of collapse of AHP. Twenty-two patients had chin-down AHP. Recession-resection (bilateral superior rectus recession 6-9mm; bilateral inferior rectus resection 5-9mm) was performed in 11 cases; weakening of both elevators (bilateral superior rectus recession 5-8mm, bilateral inferior oblique recession or myectomy) occurred in 11 cases. Unfavorable outcome rates were 64% (7/11) compared with 18% (2/11), respectively (P= .03). Reoperation was performed for 6 of 22 patients. Five patients were from the recession-resection group, namely 3 for induced V-pattern esotropia, 1 for alternating esotropia, and 1 to correct recurrent AHP. The last of the 6 who required reoperation was in the elevator weakening group, and required correction of a recurrent AHP (P= .06). While recession-resection of the vertical recti and weakening of both elevators each produce acceptable collapse of chin-down AHP, the former frequently induces a V-pattern esotropia requiring reoperation.

Surgical Management of Primary Inferior Oblique Muscle Overaction: A Subgroup-Specific Surgical Approach.

Objectives:The aim of this research was to assess the surgical results of recession and myectomy procedures in a subgroup of patients who had primary inferior oblique muscle overaction.Methods:The records of 94 patients who had been treated due to primary inferior oblique muscle overaction were retrospectively analyzed. The patients were classified into 2 groups according to the severity of the inferior oblique hyperfunction. Recession was performed for patients with a low grade (+1 or +2) inferior oblique hyperfunction, and patients with high grade (+3 or +4) hyperfunction underwent myectomy surgery. Patients demonstrating a horizontal misalignment underwent conventional horizontal muscle surgery along with an inferior oblique weakening procedure.Results:A total of 134 eyes fulfilled the inclusion criteria. Recession was performed in 95 eyes and myectomy in 39. Surgical success was obtained in 96.8% of the eyes that underwent recession and 97.4% of the eyes that underwent myectomy. Residual inferior oblique hyperfunction was observed in 3 eyes after recession and in 1 eye after myectomy. After surgery, about one-quarter of the patients with unilateral inferior oblique overaction subsequently developed a contralateral inferior oblique overaction.Conclusion:The results of this study demonstrated that both recession and myectomy procedures are effective for treating primary inferior oblique hyperfunction with minimal complications when applied in the appropriate patient.

Effect of Isolated Oblique Muscle Weakening Procedures on Horizontal Deviation in A- and V-pattern Exotropia

ABSTRACTPurpose: To evaluate the effect of isolated oblique muscle weakening on horizontal deviation in patients with A- and V-pattern exotropia.Methods: The medical records of patients who underwent bilateral oblique muscle weakening for A- and V-pattern exotropia associated oblique muscle overaction between 2011 and 2018 were reviewed. The primary outcome measures were the angle of horizontal deviation and the amount of pattern collapse.Results: Forty-three patients had A-pattern exotropia with bilateral superior oblique muscle overaction (SOOA) and underwent superior oblique (SO) weakening, while 44 patients had V-pattern exotropia with inferior oblique muscle overaction (IOOA) and underwent inferior oblique (IO) weakening. There were significant differences in exodeviation at near and distance between measurements obtained before and after oblique muscle weakening procedures (p < .05). The mean horizontal esoshift at distance was 7.9 PD in patients who underwent SO weakening and 9.5 PD in patients who underwent IO weakening. The mean postoperative collapse was 24.6 PD for A-pattern and 10.1 PD for V-pattern exotropia.Conclusion: The oblique muscle weakening procedures have secondary effects and reduce horizontal exodeviation. This study suggests that surgeons should be aware of the effects of oblique muscle weakening on horizontal deviation and pattern collapse of when planning and performing strabismus surgery.

Surgical outcomes of inferior oblique muscle weakening procedures for eliminating inferior oblique muscle overaction: a prospective randomized study

Purpose The aim of this study was to evaluate the outcomes of weakening surgical procedures for eliminating inferior oblique muscle overaction (IOOA). Patients and methods A prospective randomized interventional study was performed on 20 eyes of 12 patients with IOOA. The eyes were classified randomly into three groups. The first group included six eyes treated with inferior oblique (IO) myotomy. The second group included eight eyes treated with IO myectomy. The third group included six eyes treated with IO muscle recession. The ductions, versions, and degree of IOOA were analyzed in all patients before and after surgery. Patients were included in the study only if they achieved a minimal follow-up period of 3 months. Results Orthotropia was achieved in 13 (65%) eyes: three (15%) eyes in IO myotomy group, five (25%) eyes in IO myectomy group, and five (25%) eyes in IO recession group. One (5%) eye of IO myotomy group showed residual degree of IOOA. Underaction of IO occurred in one (5%) eye of IO myectomy and recurrence occurred in five (25%) eyes of all groups. Conclusion Recession is the most effective procedure to eliminate IOOA, whereas myectomy at insertion is the second most effective procedure and myotomy is the least effective procedure.

Anterior superior oblique tuck: an alternate treatment for excyclotorsion

Excyclotorsion is typically treated with surgical procedures such as the Harada-Ito, rectus muscle transposition, and inferior oblique weakening. We describe an alternative technique, the anterior superior oblique tuck. This procedure is technically simpler than the Harada-Ito and provides similar results.

The Effect of Strabismus Muscle Surgery on Corneal Biomechanics.

Purpose Studying the early effect of different extraocular muscle (EOM) surgeries on corneal biomechanics. Subjects and methods This is a prospective, nonrandomized, interventional study, in which 42 eyes of 29 candidates for EOM surgery for strabismus correction at Cairo university hospitals, aged 14–37 years, were recruited. All participants had measuring of the visual acuity, refraction (spherical equivalent (SE)), assessment of the EOM motility and muscle balance, sensory evaluation, fundus examination, and assessing the ocular biomechanics using the Ocular response analyzer (ORA, Reichert, INC., Depew, NY) noting the corneal hysteresis (CH) and corneal resistance factor (CRF) preoperatively. Same patients were reassessed using ORA 4 weeks postoperatively following a different standard EOM surgery (recti weakening/strengthening and inferior oblique weakening either (graded recession) according to the surgical indication, and ∆CH and ∆CRF were calculated, each is the preoperative − the postoperative value. Results ∆CH and ∆CRF = −0.78 ± 1.56 and −0.72 ± 2.15, respectively, and a highly significant difference was found between each of the pre- and postoperative CH and CRF (p < 0.001). 18 eyes had single EOM surgery, while 24 had multiple (2 or 3) EOM surgery; ∆CH in the single group = −1.28 ± 1.5, and ∆CH in the multiple group = 0.4 ± 1.49 (p=0.07). 23 eyes had EOM weakening surgery, while 18 had combined weakening and strengthening EOM surgery: ∆CH in the weakening group = −1.24 ± 1.77 and ∆CH in combined group = −0.26 ± 1.07 (p=0.04). A nonsignificant difference was found for ∆CRF (p=0.53). Conclusion A different EOM surgery has an early tendency for increase of the postoperative CH specially for muscle weakening procedures (recti recession/inferior oblique muscle weakening).