Superior Oblique Palsy Research Articles

One- vs two-muscle surgery for unilateral fourth nerve palsy

Classic teaching regarding surgery for unilateral fourth nerve palsy is one muscle for 15pd or less in primary and two muscles for greater than 15Δ, but surgeons still disagree on one versus two muscles for 14Δ-25Δ deviations. We compared outcomes of one- versus two-muscle surgery.

Complete ophthalmoplegia, complete ptosis and dilated pupil due to internal carotid artery dissection: as the first manifestation of Takayasu arteritis

BackgroundTakayasu arteritis is a rare, chronic large vessel vasculitis involving the aorta and its primary branches. As the disease progresses, the active inflammation of large vessels leads to dilation, narrowing and occlusion of the arteries. Arterial dissection is due to separation of the layers of the arterial wall resulting in a false lumen, where blood seeps into the vessel wall. Neurological sequelae of intracranial arterial dissection results from cerebral ischemia due to thromboembolism and hypo perfusion. Internal carotid artery dissection in Takayasu arteritis is very rare and complete ophthalmoplegia due to internal carotid artery dissection is also rare. This is the first case report of Takayasu arteritis presenting as complete ophthalmoplegia due to internal carotid artery dissection.Case presentationA 38-year-old Sri Lankan female presented with sudden onset severe headache, fixed dilated pupil, complete ptosis and ophthalmoplegia on the right side. On imaging, dissection and dilatation was evident in the right internal carotid artery from the origin up to the cavernous segment. She also had stenosis and aneurysmal dilatation of right subclavian artery. Takayasu arteritis was diagnosed subsequently. She was started on aspirin and high dose steroids.ConclusionsInternal carotid artery dissection within the cavernous sinus can lead to third, fourth and sixth nerve palsy due to compression, stretching and ischemia from occlusion of the nutritional arteries. This case report illustrates that internal carotid artery dissection should be a differential diagnosis in palsies of the third, fourth, or sixth cranial nerves, especially when associated with headache. In cases of internal carotid artery dissection, vasculitis such as Takayasu arteritis should also be considered.

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.

Are we overlooking masked bilateral congenital superior oblique palsy in children: is it possible to diagnose before surgery?

To describe the characteristics of children who had subsequent contralateral superior oblique underaction (SOUA) and inferior oblique overaction (IOOA) after unilateral inferior oblique weakening surgery and to identify suggestive clinical features for masked bilateral fourth nerve palsy. The medical records of children who underwent unilateral inferior oblique tenotomy as a single procedure for unilateral superior oblique palsy were all reviewed. Diagnosis was based on evaluation of ocular misalignment in nine diagnostic gaze positions and presence of SOUA, IOOA, and abnormal head position. The study was conducted with 29 children. All children had preoperative unilateral IOOA and SOUA. Eleven children (37.9%) had hyperesodeviation in the affected eye, while others (62.1%) had hyperexodeviation. The mean age at surgery was 6.66±1.87 (4-10) years. The mean vertical deviation, exodeviation, and the amount of IOOA were decreased postoperatively (p<0.001 for all). Among the 29 children, 22 had no residual ipsilateral IOOA, 2 had ipsilateral IOOA, and 5 had ipsilateral inferior oblique underaction (IOUA) at last visit. Three children had contralateral SOUA, IOOA, and hyperdeviation at follow-up visits, one of whom had IOUA on the operated eye. There was no difference of preoperative features between children with or without subsequent contralateral superior oblique palsy. Bilateral congenital superior oblique palsy may be overlooked in children in spite of detailed preoperative evaluation. Masked bilaterality should always be kept in mind in cases with unilateral pathology. Patients should be informed about the possibility of bilaterality.

One- Versus Two-Muscle Surgery for Presumed Unilateral Fourth Nerve Palsy Associated With Moderate Angle Hyperdeviations

To compare 1-muscle vs 2-muscle surgery for moderate-angle hyperdeviations owing to presumed unilateral fourth nerve palsy. Retrospective chart review. Seventy-three patients (aged 5-86 years) underwent either 1- or 2-muscle surgery at our institution for moderate hyperdeviation owing to presumed unilateral fourth nerve palsy, measuring 14-25 prism diopters (PD) in straight-ahead gaze at distance fixation. Six-week and 1-year motor success was defined as zero vertical deviation or 1-4 PD undercorrection at distance, overcorrection as any reversal of hypertropia, and undercorrection as >4 PD. Diplopia success was defined as no diplopia, or only rarely for distance straight ahead and reading. Twenty-eight patients underwent 1-muscle surgery, and 45 patients underwent 2-muscle surgery. Motor success was similar (64% vs 67%, P > .99 at 6weeks; 47% vs 55%, P= .8 at 1 year, n= 46), but there were more undercorrections at 6weeks with 1-muscle surgery (36% vs 16%, P= .09) and more overcorrections at 6weeks with 2-muscle surgery (0% vs 18%, P= .02). Diplopia success was also somewhat similar between 1- and 2-muscle surgery at 6weeks (73% vs 60%, P= .5) and 1 year (45% vs 59%, P= .5). For moderate-angle hyperdeviations owing to presumed unilateral fourth nerve palsy, there appears no clear advantage of 2-muscle surgery for motor outcomes. Diplopia success was similar between 1- and 2-muscle surgery, owing to a greater number of less symptomatic undercorrections with 1-muscle surgery and a smaller number of more symptomatic overcorrections with 2-muscle surgery.

Neurological Imaging in Acquired Cranial Nerve Palsy: Ophthalmologists vs. Neurologists

ABSTRACTPurpose: Cranial nerve palsies often require neurological imaging by MRI. Guidelines on whether or not to utilize MRI have been absent or lack clarity. In daily practice, both neurologists and ophthalmologists treat patients with cranial nerve palsy and determine whether neuro-imaging is required. There appear to be differences in policy with respect to neuro-imaging. The question, which will be answered in this study, is the following: to what extent do differences in policy exist between ophthalmologists and neurologists regarding imaging by MRI of patients with acquired ocular cranial nerve palsy?Method: PubMed database was searched for literature on acquired cranial nerve palsy and MRI scanning performed by ophthalmologists and neurologists. Case series published between 2000 and 2015 were included. The first author screened the literature on eligibility, profession of the authors, and conducted data abstraction.Result: Ten case series were found eligible for analysis. A total of 889 cranial nerve palsies were described, 770 by ophthalmologists and 119 by neurologists. The age range of patients in all case series was 2 to 96 years of age. The oculomotor nerve was investigated in 162 patients, the trochlear nerve in 131 patients, and the abducens nerve in 486 patients. All neurologists (n=3) and 2 out of 7 investigated ophthalmologists recommended performing MRI scanning in every patient who presented with an ocular cranial nerve palsy, while 5 ophthalmologists (5/7) opted to triage patients for risk factors associated with cranial nerve palsies prior to ordering MRI imaging. When different groups of patients were viewed separately, it became apparent that almost all specialists agreed that every patient with a third nerve palsy and patients under 50 years of age should undergo MRI scanning. In patients with fourth nerve palsy, MRI scanning was not indicated.Conclusion: The neurologists in this study were more likely to perform MRI scanning in every patient presenting with ocular cranial nerve palsy. Ophthalmologists were more likely to determine risk factors associated with cranial nerve palsy, which they took into account when deciding whether or not to perform neurological imaging in patients aged more than 50 years or presenting with abducens nerve palsy.

P.067 Steroid responsive life threatening acute hemorrhagic encephalomyelitis (AHEM) in a child with sickle cell disease (SCD)

Background: AHEM is a rare form of acute disseminated encephalomyelitis (ADEM) characterized by fulminant encephalopathy with hemorrhagic necrosis and most often fatal outcome. Methods: A case report and review of literature. Results: A 6-year-old girl known SCD presented an acute demyelinating syndrome (ADS) with diplopia due to unilateral fourth nerve palsy. She received (20mg/kg/day for 5 days) of IVMP (intravenous methylprednisolone). Two weeks after steroid weaning, she presented right hemiplegia. Brain MRI showed a left frontal necrotico-hemorrhagic lesion and new areas of demyelination. She showed signs of herniation and underwent craniotomy. Investigations ruled out vascular and infectious process in both events. The deterioration stopped concomitantly to the initiation of IVMP. She was discharged with a longer oral wean. Later, she was diagnosed with Crohn’s disease and primary sclerosing cholangitis. We considered AHEM as the most plausible diagnosis based on the clinical and radiological presentation, the preceding ADS, the exclusion of other etiologies, and the response to IVMP including resolution of non-necrotic lesions. Similar - but fatal - AHEM has been reported in 2 SCD patients. Conclusions: In any ADS occurring in the context of SCD and/or auto-immune condition, we recommend to slowly wean steroids, and to closely monitor the patient after weaning to quickly treat any recurrence with IVMP.

Combined Surgery for Simultaneous Treatment of Congenital Ptosis and Coexisting Strabismus.

To evaluate the clinical outcomes of single-stage surgery for treatment of patients with congenital ptosis and coexisting strabismus. A retrospective analysis was performed on 10 patients (17 eyes) with congenital ptosis and coexisting strabismus. Patients were treated with levator resection or frontalis suspension for ptosis and ocular muscle surgery for strabismus, performed as a single-stage procedure. Levator resection was performed in 9 patients (15 eyes) and frontalis muscle flap suspension was performed in 1 patient (2 eyes) with blepharophimosis. Seven patients (11 eyes) simultaneously underwent exotropia correction, and inferior oblique myectomy was performed in 3 patients (3 eyes) with congenital superior oblique palsy. Satisfactory efficacy of single-stage surgery for correction of congenital ptosis and coexisting strabismus was achieved without complications. Comprehensive preoperative examination is vital to determine the appropriate diagnosis and guide surgical decision-making. Single-stage surgery for congenital ptosis and coexisting strabismus is effective and a shortened treatment period is beneficial to patients. [J Pediatr Ophthalmol Strabismus. 2017;54(5):288-294.].

Adjustable Bilateral Superior Oblique Tendon Advancement for Bilateral Fourth Nerve Palsy

Bilateral fourth nerve palsy may be symmetric or asymmetric with combined vertical and excylotropic deviations and so there may be an advantage to independent adjustment of vertical and torsional components. We report a surgical technique that allows such independent adjustment. Retrospective interventional case series. Fifteen patients, aged 17-73 years, underwent adjustable bilateral superior oblique tendon advancements for bilateral fourth nerve palsy: 11 symmetric (≤2 prism diopters [pd] hyperdeviation in straight-ahead gaze) and 4 asymmetric. Motor alignment was assessed with double Maddox rods and prism and alternate cover tests preoperatively, pre- and postadjustment, and 6weeks postoperatively. Preoperative torsion ranged from 7 to 30 degrees excyclotropia (mean 17 ± 7 degrees) and hyperdeviation from 0 to 10 pd. Preadjustment torsion ranged from 5 degrees excyclotropia to 40 degrees incyclotropia, and hyperdeviation from 0 to 8 pd. Twelve of the 15 patients (80%) were adjusted to a target of 0 pd hyperphoria and 10 degrees incyclotropia (actual mean 9 degrees incyclotropia, range 2-13 degrees incyclotropia). At 6weeks postoperatively there was expected excyclodrift (to mean 4 degrees excyclotropia, range 0 degrees incyclotropia to 15 degrees excyclotropia), but 13 (87%) had 5 degrees or less excyclotropia and 14 (93%) had 2 pd or less hyperdeviation. Mean torsional correction from preoperative to preadjustment was 31 ± 14 degrees (P < .0001), and from preoperative to 6weeks was 13 ± 6 degrees (P < .0001). Adjustable bilateral superior oblique tendon advancement allows independent control of torsional and vertical components of the deviation, and therefore may be useful in cases of bilateral superior oblique palsy.

Effect of modified graded recession and anteriorization on unilateral superior oblique palsy: a retrospective study

BackgroundSeveral inferior oblique (IO) weakening methods exist for correction of superior oblique palsy (SOP). A previously reported method involved recession and anteriorization according to IO overaction (IOOA) grade, which might be subjective and cause upgaze limitation and opposite vertical strabismus. Therefore, this study attempted to examine the efficacy of modified graded recession and anteriorization of the IO muscle in correction of unilateral SOP without resulting in upgaze limitation or opposite vertical strabismus.MethodsA total of 26 patients (male, 16; female, 10; age: 3–40 years) with SOP and head tilt or diplopia underwent modified graded recession and anteriorization. Patients were grouped by the position at which the IO muscle was attached inferior/temporal to the lateral border of the inferior rectus (IR) as follows: (1) 7.0/2.0 mm (4 patients), (2) 6.0/2.0 mm (3 patients), (3) 5.0/2.0 mm (3 patients), (4) 4.0/2.0 mm (11 patients), (5) 3.0/0.0 mm (2 patients), and (6) 2.0/0.0 mm (3 patients). Recession and anteriorization were matched to vertical deviation in the primary position at far distance. Remaining diplopia, head tilt, vertical deviation (≤3 prism diopter (PD), excellent; 4–7 PD, good; and ≥ 8 PD, poor), upgaze limitation, and opposite vertical strabismus were evaluated.ResultsThe average pre and postoperative 1-year vertical deviation angles in the primary position at far distance were 15.0 ± 5.6 PD and 1.2 ± 2.0 PD, respectively. At 1 year post-surgery, the vertical deviation angles were reduced by 6.8–21.0 PD from those at baseline. Few patients exhibited remaining head tilt, diplopia, upgaze limitation, or opposite vertical strabismus. Correction of hypertropia was excellent in 22 and good in 4 patients.ConclusionsModified graded recession and anteriorization of the IO muscle is an effective surgical method for treating unilateral SOP. It exhibits good results and reduces the incidence of opposite vertical strabismus.

The observation on efficacy of surgery for congenital unilateral superior oblique palsy

Objective To observe the efficacy of the surgery for congenital unilateral superior oblique palsy. Methods The medical records of 124 patients that underwent surgery for congennital unilateral superior oblique palsy from Oct. 2014 to Dec.2015 at Shanxi Eye Hospital were retrospectively reviewed. The chinical feature, the surgical procedures and efficacy were analyzed. Results The patients were followed up for 5-14 months after surgery. There were 110 cases recovered(88.71%), 12 cases improved(9.68%), and 2 cases invalid(1.61%). Conclusion Surgery is an effective method for congenital superior oblique palsy, the effectiveness rate is over 98%. Key words: Superior oblique palsy, congenital, unilateral; Surgery; efficacy

Surgical treatment of superior oblique palsy: Predictors of outcome.

Purpose:The purpose of this study was to evaluate the incidence and outcome of surgically treated superior oblique palsy (SOP) and the factors involved in its resolution.Methods:We performed a retrospective study of 76 patients who underwent surgery for SOP. We recorded data from the physical examination and the number and type of procedures performed. Favorable outcome was defined as resolution of or improvement in torticollis (≤5°) and diplopia in primary position (PP) and downgaze or as vertical deviation (VD) <5 prism diopters (pd) in PP and 10 pd in the oblique diagnostic position.Results:Mean age was 33.12 years. Congenital SOP was the most frequent type (65.8%). Mean preoperative VD was 15.89 ± 9.94 pd, decreasing to 3.07 ± 4.36 pd after surgery. Associated horizontal deviation was recorded in 51.32% of cases. The mean number of procedures was 1.37 ± 0.62 (range 1–4), with 69.7% of patients requiring only one procedure. The mean number of muscles operated on was 1.96 ± 1.01 (inferior oblique being the most frequent). A greater reduction in VD after surgery was observed in patients with congenital SOP (P = 0.04). Although none of the factors evaluated influenced surgical outcome, amblyopic patients had a greater risk of reoperation (P = 0.04). A favorable outcome was achieved in 75% of cases. Mean follow-up was 37.08 months.Conclusion:Congenital SOP was twice as frequent as acquired SOP and although surgery was successful in most cases, a greater reduction in VD was obtained in congenital cases. Amblyopia was identified as a risk factor for reoperation.

A Case of Dural Arteriovenous Fistula of Cavernous Sinus with Trochlear Nerve Palsy, Oculomotor Nerve Palsy and Horner Syndrome

A Case of Dural Arteriovenous Fistula of Cavernous Sinus with Trochlear Nerve Palsy, Oculomotor Nerve Palsy and Horner Syndrome

Imaging of Cranial Nerves III, IV, VI in Congenital Cranial Dysinnervation Disorders.

Congenital cranial dysinnervation disorders are a group of diseases caused by abnormal development of cranial nerve nuclei or their axonal connections, resulting in aberrant innervation of the ocular and facial musculature. Its diagnosis could be facilitated by the development of high resolution thin-section magnetic resonance imaging. The purpose of this review is to describe the method to visualize cranial nerves III, IV, and VI and to present the imaging findings of congenital cranial dysinnervation disorders including congenital oculomotor nerve palsy, congenital trochlear nerve palsy, Duane retraction syndrome, Möbius syndrome, congenital fibrosis of the extraocular muscles, synergistic divergence, and synergistic convergence.

Pseudoamblyopia in Congenital Cyclotropia.

Purpose To study the effect of surgery on amblyopia and suppression associated with congenital cyclovertical strabismus. Methods The fixation pattern was investigated with microperimetry before and soon after surgery in ten consecutive children operated for congenital superior oblique palsy at the S. Martino Hospital, Belluno, Italy, between September 2014 and December 2015. Changes in visual performance in terms of best-corrected visual acuity (BCVA) and stereopsis between the day before and one week after surgery were also evaluated. No other amblyopia treatment has been administered during the time study. Results Surgical correction of the excyclodeviation in congenital SO palsy determined monocular and binocular sensory consequences: monocularly, in the cyclodeviated amblyopic eye, BCVA (0.46–0.03 LogMAR; p < 0.0001) and the fixation pattern improved, as demonstrated by microperimetry examination. Binocularly, stereopsis improved or emerged while suppression at the Worth four-dot test disappeared. Conclusions In the absence of further amblyopic factors such as coexisting constant vertical and/or horizontal deviation and anisometropia, the amblyopia encountered in congenital SO palsy may resolve soon after the surgical alignment. Therefore, it may be considered and defined “pseudoamblyopia.”

Changing Strabismus Surgery Distribution at Shanxi Province Eye Hospital in Central China.

To investigate whether there has been a changing trend of strabismus surgery in a provincial eye hospital in the central part of China over the past decade. This was a retrospective analysis of data on all strabismus surgery performed in Shanxi Province Eye Hospital in China during the past 10 years. Recorded characteristics included patient demographics, type of strabismus, age, and gender. A total of 12,327 patients received strabismus surgery in the eye hospital from 2005 to 2014. The number of surgeries increased steadily from 800 in 2005 to 1,723 in 2014 (P < .01). Constant exotropia was the most common type among all types of strabismus. Superior oblique muscle palsy was the most common type of paralytic strabismus. Exotropia oblique A- and V-pattern type was the most common type of special strabismus. The amount of strabismus surgery increased during the past decade. The proportion of patients with intermittent exotropia increased over time compared to those with other types of strabismus. [J Pediatr Ophthalmol Strabismus. 2017;54(2):112-116.].

The Development of Hypertrophic Inferior Olivary Nucleus in Oculopalatal Tremor

ABSTRACTOculopalatal tremor is an acquired clinical condition resulting from the interruption of the dentato-rubro-olivary neuronal pathway. The signal change in inferior olivary nucleus and its hypertrophy on magnetic resonance imaging (MRI) can be observed prior to the development of symptomatic oculopalatal tremor. This is a case of the fourth cranial nerve palsy followed by oculopalatal tremor, and increased signal intensity in inferior olivary nucleus on MRI was observed in 7 months after damage to the dentate-rubro-olivary pathway and 5 months prior to the development of oscillopsia and oculopalatal tremor.

Extraocular Muscle Compartments in Superior Oblique Palsy.

PurposeTo investigate changes in volumes of extraocular muscle (EOM) compartments in unilateral superior oblique (SO) palsy using magnetic resonance imaging (MRI).MethodsHigh-resolution, surface-coil MRI was obtained in 19 patients with unilateral SO palsy and 19 age-matched orthotropic control subjects. Rectus EOMs and the SO were divided into two anatomic compartments for volume analysis in patients with unilateral SO palsy, allowing comparison of total compartmental volumes versus controls. Medial and lateral compartmental volumes of the SO muscle were compared in patients with isotropic (round shape) versus anisotropic (elongated shape) SO atrophy.ResultsThe medial and lateral compartments of the ipsilesional SO muscles were equally atrophic in isotropic SO palsy, whereas the lateral compartment was significantly smaller than the medial in anisotropic SO palsy (P = 0.01). In contrast to the SO, there were no differential compartmental volume changes in rectus EOMs; however, there was significant total muscle hypertrophy in the ipsilesional inferior rectus (IR) and lateral rectus (LR) muscles and contralesional superior rectus (SR) muscles. Medial rectus (MR) volume was normal both ipsi- and contralesionally.ConclusionsA subset of patients with SO palsy exhibit selective atrophy of the lateral, predominantly vertically acting SO compartment. Superior oblique atrophy is associated with whole-muscle volume changes in the ipsilesional IR, ipsilesional LR, and contralesional SR; however, SO muscle atrophy is not associated with compartmentally selective volume changes in the rectus EOMs. Selective compartmental SO pathology may provide an anatomic mechanism that explains some of the variability in clinical presentations of SO palsy.

Complete 3rd cranial nerve dysfunction postdeflation/ excision of an encasing pituitary macroadenoma intrasellular cyst: A Case Report

Abstract Central nervous system injury in particular cranial nerve palsy has been reported to be as high as 2%. Such prevalence of palsy generally attributed to surgical manipulation at the cavernous sinus, especially incurring the abducens nerve. We report the first case of acute oculomotor nerve sequel to the release of cystic fluid wrapping the nerve following a transsphenoidal excision of pituitary macroadenoma in a 57-year-old woman. She attended with the presentation of acute excruciating headache associated with partial drooping of right eye. The computed tomography and magnetic resonance imaging (MRI) were consistent with pituitary apoplexy of an underlying pituitary macroadenoma. Urgent transsphenoidal hypophysectomy was done. Intra-operatively, cystic fluid was aspirated during pituitary tumour dissection. At the same time, curettage was employed to removal residual tumour after the tumour biopsy. Immediate post-operative assessment noted complete right eye ptosis, with clinical evidence of complete right third and fourth nerve palsies. MRI was repeated a week later in view of such palsy non-resolution. However, no local compression or edema noted. Observation and monitoring were opted versus surgical revision. Propitiously the aforementioned cranial nerve palsies persist for a month and subsequently subsided. In this case, we highlight the potential deleterious impact of aspirating cystic component and curettaging during pituitary surgery. Likely postulated accounts for such occurrence include sudden release of fluid pressure with resultant cystic traction on its enfolding cranial nerves and subsequent neuropraxia. We aim to invite comments that could enlighten us on this gray area.

Clinical observation of the graduated "hang-back" recession of superior oblique in a-pattern strabismus with superior oblique overaction

To investigate the effect and safety of the graduated "hang-back" recession of superior oblique (SO) in treatment of A-pattern strabismus with superior oblique overaction (SOOA). Retrospective study. The clinical data of 15 cases (28 eyes), who underwent graduated "hang-back" recession of SO depending on the scales of SOOA, were collected and analyzed. The principle we carried on was hang-back recession 8-10mm for SOOA+4, 6 to 8 mm for SOOA+3, 5 to 6 mm for SOOA+2 and 4 mm for SOOA+1. The pre-operative and post-operative outcomes, including the ocular alignment, ocular motility, A-pattern and objective torsion demonstrated by fundus photographs were evaluated and compared. In 15 cases (28 eyes), 2 cases had unilateral hang-back recession of SO for unilateral SOOA. Thirteen cases had bilaterally symmetric or asymmetric hang-back procedure. All the patients had no A pattern after surgery. The average difference of pre- and post-operative A-patterns were (24.5±11.9) PD and (3.2±4.2) PD in 13 cases with bilateral SOOA (t=8.01, P=0.00). The bilateral SO hang-back procedure could correct A-pattern in an amount of 21.3±10.3 PD in average. The average amount of pre- and post-operative SOOA were +3.0±2.0 and +0.5±1.0 in 28 eyes (Z=-4.70, P=0.00). Only 1 case remained residual SOOA+2.0. Fundus photos were measured by SigmascanPro5.0 program and the average pre- and post-operative torsion were +5.4°±3.9°and +0.3°±5.6° (The baseline was the line across the center of optic disc. The torsional angle was measured between the line across the fovea and and the line across the center of optic.) in 28 eyes (t=5.76, P=0.00). The average corrected torsion was 5.2°±4.8°. The pre-operative SOOA was related with the pre-operative torsion (Spearman correlation coefficient=0.47, P=0.01). The surgical amounts in 28 eyes were various from 4 to 10 mm (8±12 mm in average), which were not related with the corrected torsion (Spearman correlation coefficient=0.17, P=0.39), but related with pre-operative torsion (Spearman correlation coefficient=0.44, P=0.02). The total amounts on both eyes in patients operated by bilateral SO hang-back procedure were also not related with the corrected A-pattern (Spearman correlation coefficient=0.55, P=0.05). No case had secondary SO palsy and V-pattern after surgery. The graduated "hang-back" recession of SO is optional for treatment of mild to moderate SOOA and A-pattern. It corrected objectively in-torsion without risks of secondary SO palsy and V-pattern. It is a safe and effective SO weakening procedure. (Chin J Ophthalmol, 2016, 52: 579-583).