Compensatory Head Posture Research Articles

Boergen modification of Harada-ito surgery with and without vertical muscle surgery for acquired unilateral superior oblique muscle palsy.

The purpose is to report the results of the Boergen modification of the Harada-Ito procedure with and without simultaneous vertical muscle surgery in patients with acquired unilateral superior oblique muscle palsy. Files of patients with acquired unilateral superior oblique muscle palsy who were treated with Boergen modification of the Harada-Ito procedure were studied retrospectively. For each patient, age at the time of surgery, the presence of diplopia, compensatory head posture, and ocular deviation before and after surgery were retrieved. Results were evaluated 6 months after surgery. A total of 12 patients with a mean age of 32 years at the time of surgery (range 15-45 years) were included. The underlying etiology was head trauma in eleven patients. The modified Harada-Ito procedure alone was done for three cases (Group 1), and a simultaneous combination of this procedure and vertical muscle surgery was performed in nine patients (Group 2). The average intorsional effect in the primary position was 9.2° (8° in Group 1 and 9.6° in Group 2). The average correction of hypertropia in the primary position was 8.2 prism diopters (PD) (1 PD in Group 1 and 10.6 PD in Group 2). Diplopia in the primary position and downgaze were resolved in eleven patients and ten patients, respectively. Four patients had a compensatory head tilt at their last follow-up. Boergen modification of the Harada-Ito procedure, alone and combined with vertical muscle surgery, successfully corrected primary position diplopia in the majority of the patients.

Clinical effect of superior oblique re-tucking for recurrent or residual compensatory head position

Objective: To evaluate the effects of re-tucking the superior oblique muscle on recurrent or residual compensatory head position. Methods: A retrospective case series study was conducted. 12 recurrent or residual compensatory head position patients (12 eyes) with congenital superior oblique palsy who underwent superior oblique re-tucking in Tianjin Eye Hospital from March 2015 to February 2021 were included. All patients had a history of superior oblique tucking procedure and showed signs of superior oblique muscle palsy without inferior oblique muscle overaction. During surgery, the Guyton forced duction test is used to evaluate the relaxation of the superior oblique muscle tendon, which affects the re-tucking length of the muscle.Their head position, vertical deviation, eye movement, fovea-disa angle, and Bielschowsky head tilt test were assessed pre-and post-surgery. Statistical analysis was performed using ttest and paired samples Wilcoxon signed rank test. Results: Out of the 12 patients, 8 were male and 4 were female, aged between 2 and 9 years. The initial surgery was done at age 6, with a superior oblique recession length of (7.17±1.03) mm. Recurrent head tilt occurred in 11 patients after (3.82±0.98) months postoperatively, and 1 patient had residual head tilt, with a followup period of six months or more. Ocular motility examination revealed underaction of the superior oblique muscle, positive Bielschowsky's head tilt test, and Guyton forced duction tese indicating relaxation of the paralyzed superior oblique muscle tendon. Scar adhesion was observed at the stop of the superior oblique muscle, as well as the previous sutures. The scar and the sutures around the stop of the superior oblique muscle were released, the mean re-tucking amount was(7.83±1.59)mm. Follow-up at 12 to 18 months postoperatively showed disappearance of compensatory head position, significant improvement in superior oblique muscle lag, normal ocular motility, and no occurrence of Brown syndrome. The results of Bielschowsky head tilt were negative in 9 cases and still positive in 3 cases after superior oblique re-tucking. The primary vertical deviation was 2.5 (2.0, 5.3) prism diopter pre-operatively and 1 (0, 1) prism diopter post-operatively, respectively. The difference was statistically significant (U=6.00, P<0.001). The total amount of FDA in both eyes was (-22.04±5.47)° and (-15.27±6.08)° pre-and post-operatively, respectively. The difference was statistically significant (t=2.87, P=0.009). All 12 patients have normal eye movement after superior oblique re-tucking procedure. All patients had no compensatory head position at last follow-up. Conclusions: Superior oblique re-tucking is suitable for patients with relaxation of the superior oblique muscle tendon and extrocular rotation as the main sign. It can effectively and safely correct the recurrent or residual compensatory head position after re-tucking the superior oblique muscle.

The relationship between eye canting and vertical craniofacial skeletal asymmetry in adult patients with dento-maxillofacial deformities

BackgroundWhether eye canting in patients with asymmetric dento-maxillofacial deformities is the result of anatomical asymmetry or a compensatory head position remains controversial. ObjectiveThis cross-sectional study aims to verify whether eye canting is correlated with craniofacial skeletal asymmetry. Methods & materialsThis study was performed by measuring the computed tomographic scans of 223 patients with dento-maxillofacial deformities in Mimics 21.0 software. First grouping was determined based on the intersection angle between the line passing through bilateral lateral canthus point and Frankfurt horizontal plane, and final grouping was based on measurements of the pregroups. ResultsThe patients were finally categorized into three groups: symmetry group (n = 163), asymmetry subgroups 1 (n = 33) and asymmetry subgroups 2 (n = 27). The results of multiple linear regression and comparisons among groups suggests the presence of orbital skeletal asymmetry in patients with eye canting and the eye canting is partly increment dependent of orbital skeletal asymmetry when using bilateral ears as the reference. The result also reveals that there is a greater angle between the line through bilateral ocular landmarks and the line through the bilateral ear landmarks in patients with ocular canting compared to patient without eye canting. ConclusionPatients with asymmetric dento-maxillofacial deformities and with eye canting have vertical asymmetry of the orbital and cranial skeletal landmarks. These symmetry differences between the eyes and ears may affect the overall craniofacial symmetry after orthognathic surgery

Clinical efficacy of modified Yokoyama procedure with extraocular muscle transposition for high myopic eyes with restrictive esotropia

Objective: To investigate the clinical efficacy of the modified Yokoyama procedure with extraocular muscle transposition for high myopic eyes with restrictive esotropia. Methods: A retrospective case series study was conducted. Clinical data were collected from patients who underwent the modified Yokoyama procedure with extraocular muscle transposition for high myopic eyes with restrictive esotropia at Eye Hospital of Shandong First Medical University from February 2017 to February 2022. During the procedure, the superior rectus and lateral rectus muscles were fully separated. A longitudinal blunt incision was made in the central muscle belly extending posteriorly to 12-14 mm from the muscle insertion. The temporal half of the superior rectus muscle and the upper half of the lateral rectus muscle belly were transposed and secured to the contralateral muscle insertion. Simultaneously, medial rectus muscle recession was performed. Follow-up visits were conducted at 1 week, 1 month, 3 months, and 6 months postoperatively. Patients' ocular alignment, eye movements, improvement in compensatory head posture, objective degrees of strabismus using synoptophore, changes in extraocular muscles and globe position on orbital CT scan were recorded. Surgical complications were also documented. Results: Five patients (8 eyes) were included in this study, including 4 females (7 eyes) and 1 male (1 eye), with an average age of (63±11) years and an average axial length of (34.58±2.25) mm. The medial rectus muscle recession during surgery was (7.6±2.3) mm. Preoperatively, all patients had esotropia with a horizontal range of+15°to+45° and a vertical range of+15°to+45°. Significant limitations in lateral and upward gaze were observed, with a degree of restriction ranging from-3 (-4 to-1). Three patients with bilateral involvement and one patient with unilateral involvement exhibited significant compensatory head postures. One patient with unilateral involvement had no compensatory head posture. Preoperative orbital CT scans indicated nasal displacement of the superior rectus muscle and inferior displacement of the lateral rectus muscle, with the eyeball herniating from the muscle cone. At the 6-month follow-up, all patients achieved nearly orthophoric alignment. Objective degrees of horizontal strabismus ranged from-4°to+7°, and vertical strabismus ranged from 0°to +6°, as determined by synoptophore examination. Eye movements significantly improved, with a degree of restriction of-1 (-2 to-1) for lateral gaze and-2 (-3 to-1) for upward gaze. Compensatory head postures disappeared, and orbital CT scans indicated the eyeball was located within the muscle cone. There were no severe complications such as anterior segment ischemia, muscle adhesions, disease recurrence, secondary glaucoma, or globe penetration. Conclusion: The preliminary clinical outcomes of the modified Yokoyama procedure with extraocular muscle transposition for high myopic eyes with restrictive esotropia are promising.

Outcomes of Strabismus Surgery Following Teprotumumab Therapy

PurposeTo investigate the results of patients undergoing surgical treatment for strabismic diplopia in thyroid eye disease (TED) following teprotumumab. DesignMulticenter, retrospective, case series. MethodsWe report 28 patients who underwent extraocular muscle surgery for strabismic diplopia after treatment with teprotumumab at 7 different academic centers. Elapsed time from last teprotumumab dose to the date of surgery, previous orbital decompression, primary preoperative horizontal and vertical deviation, surgical procedure, and 2-month postoperative results were collected from the patient records. ResultsSixteen (57%) patients were diplopia-free after one surgery. Three (11%) chose prism spectacles to correct residual diplopia, 2 (7%) used compensatory head posture to resolve diplopia, and 1 (4%) had intermittent diplopia and was functionally improved (choosing no prisms or further surgery). These were considered treatment successes. Three (11%) patients required reoperation, and all were diplopia-free after their second procedure. ConclusionsMost patients requiring surgery for strabismic diplopia following teprotumumab achieve good outcomes with success rates comparable to series published before the availability of teprotumumab.

Postoperative outcomes for unilateral congenital trochlear nerve palsy: A retrospective cohort study

Congenital trochlear nerve palsy is the most common cause of vertical strabismus. The goal of this study was to investigate surgical outcomes after superior oblique tendon plication with or without inferior oblique recession in children and adults with unilateral congenital trochlear nerve palsy. Data and outcomes were collected in patients with a diagnosis of unilateral congenital superior oblique palsy during a retrospective single-center study conducted at the University Hospital of Tours. A reproducible, standard ophthalmological and oculomotor examination was performed pre- and postoperatively at 1 year, including presence or absence of diplopia, vertical and horizontal deviations, and compensatory head posture. Surgical success, defined as an endpoint including absence of diplopia in primary position, absence of head tilt, and vertical deviation at distance fixation<5 prism diopters (PD), was analyzed. A total of fifty-seven patients (median [IQR] age of 11 years [5-42]) were analyzed. Patients experienced a significant reduction in vertical distance and near deviations (p<0.001), compensatory head tilt (p<0.001), and diplopia after surgery (p<0.001). Surgical success was higher in adults (17/24, 70.8%) than in children (15/33, 45.5%), although this did not reach statistical significance (p=0.0657). This study suggests that plication of the superior oblique muscle tendon, with or without recession of the inferior oblique muscle, can be effective in treating unilateral congenital trochlear nerve palsy. Further studies are necessary to compare surgical procedures and investigate their efficacy in adults compared to children in the short and long term.

Phenotype, genotype, and management of congenital fibrosis of extraocular muscles type 1 in 16 Chinese families

PurposeCongenital fibrosis of extraocular muscles type 1 (CFEOM1), a classical subtype of CFEOM, is characterized by restrictive ophthalmoplegia and ptosis. It is mainly caused by aberrant neural innervation of the extraocular muscles. This study aimed to investigate the genetic characteristics and clinical manifestations of CFEOM1 in Chinese families.MethodsThe clinical data, including ocular examinations, magnetic resonance imaging (MRI), and surgical procedures of affected individuals from 16 Chinese CFEOM1 families, were collected. The genomic DNA of 16 probands and their family members were sequenced for causative KIF21A gene mutations. Linkage analysis using microsatellite markers across KIF21A was also conducted.ResultsAffected individuals were presented with bilateral non-progressive ptosis, restricted horizontal eye movement, fixed infraduction of both eyes, compensatory chin-up head position, and neuromuscular abnormalities. Three heterozygous KIF21A mutations, c.2860C > T (p.R954W) (in eight families), c.2861G > T (p.R954L) (in two families), and c.2861G > A (p.R954Q) (in two families) were identified, which implied that hotspot mutations were common in Chinese CFEOM1 families. Germline Mosaicism was likely to be the cause of affected individuals with asymptomatic parents without KIF21A mutations presented in the eight families. Two affected individuals underwent modified levator muscle complex suspension surgery and achieved a good result without any complications.ConclusionInstead of evaluating the whole CFEOM1 gene variant, hotspot mutations could be given priority for screening. The occurrence of germline mosaicism has to be taken into account in genetic counseling. Patients with CFEOM1 who have ptosis may benefit from an innovative surgical procedure called modified levator muscle complex suspension.

Endocannabinoid dysfunction in neurological disease: neuro-ocular DAGLA-related syndrome.

The endocannabinoid system is a highly conserved and ubiquitous signalling pathway with broad-ranging effects. Despite critical pathway functions, gene variants have not previously been conclusively linked to human disease.We identified nine children from eight families with heterozygous, de novo truncating variants in the last exon of DAGLA with a neuro-ocular phenotype characterized by developmental delay, ataxia and complex oculomotor abnormality. All children displayed paroxysms of nystagmus or eye deviation accompanied by compensatory head posture and worsened incoordination most frequently after waking. RNA sequencing showed clear expression of the truncated transcript and no differences were found between mutant and wild-type DAGLA activity. Immunofluorescence staining of patient-derived fibroblasts and HEK cells expressing the mutant protein showed distinct perinuclear aggregation not detected in control samples.This report establishes truncating variants in the last DAGLA exon as the cause of a unique paediatric syndrome. Because enzymatic activity was preserved, the observed mislocalization of the truncated protein may account for the observed phenotype. Potential mechanisms include DAGLA haploinsufficiency at the plasma membrane or dominant negative effect. To our knowledge, this is the first report directly linking an endocannabinoid system component with human genetic disease and sets the stage for potential future therapeutic avenues.

Botulinum Toxin for the Treatment of Nystagmus Associated with Exotropia

Purpose: Nystagmus can severely impact the visual function, lifestyle and quality of life of patients. Patient with Nystagmus may assume an abnormal compensatory head position and it can result in posture disorders. Botulinum toxin is an important treatment for much pathology of the eye, in particular for blepharospasm, strabismus and nystagmus. The mechanism of action is to prevent lease of acetylcholine in the neuromuscular junction getting the neuromuscular blockade and transient flaccid paralysis. The objective of this work is to evaluate the efficacy of botulinum toxin injection in patients with Nystagmus. Methods: n. 6 patients, (3 females and 3 males) aged 17 - 35 years, exhibiting exotropia (XT) associated with Nystagmus received an injection of Botulinum Toxin A Dysport (Ipsen) in the Lateral Muscles of each eye with a 27-gauge retrobulbar needle. Patients underwent an orthoptic and ophthalmic eye exam before and after surgery. Results: A significant reduction of the nystagmus in primary position was reported in all patients; the abnormal position of the head was noticeably reduced. Side-effects were limited and well tolerated by the patients. Conclusion: Botulinum toxin injection is a valuable treatment of Nystagmus associated with exotropia.

Surgical management of Helveston syndrome (Triad exotropia)

PurposeTo evaluate and compare different surgical approaches for the treatment of Helveston syndrome and provide further information for preoperative planning.MethodsFrom February 2008 to December 2018, data of 52 patients with Helveston syndrome were retrospectively reviewed. Different surgical approaches were selected based on the extent of A-pattern exotropia, dissociated vertical deviation (DVD), and both superior oblique muscle overaction (SOOA) with fundus photograph intorsion. Eye position, A-pattern, DVD, superior oblique muscle function, and binocular vision function were evaluated pre- and postoperatively. The average follow-up duration was 20.5 months.ResultsNine cases underwent simultaneous horizontal deviation correction with bilateral superior rectus recession, 24 underwent simultaneous horizontal deviation correction with bilateral superior oblique muscle lengthening, and 19 underwent two stages of horizontal deviation correction with superior oblique muscle lengthening, and later bilateral superior rectus recession. A-pattern, DVD, SOOA, and fundus intorsion were all collapsed in all patients postoperatively. Forty-five patients had an orthophoric eye position with considerably aligned ocular movements postoperatively. The total success rate was 86.5%. Postoperatively, eight of the 10 patients with diplopia experienced a recovery of binocular single vision and three had a recovery of rudimentary stereopsis (Titmus 3000–400 s of arc). The compensatory head posture of patients improved significantly postoperatively.ConclusionsThe surgical planning of Helveston syndrome should be designed based on the degree of the A-pattern, SOOA, DVD, and the intorsion in fundus photographs, and the appropriate approach should be selected to improve patient satisfaction.

Infranuclear Eye Movement Disorders.

Infranuclear motility disorders are such of the cranial nerves, the extraocular muscles or changes in the orbit but definitely peripheral to the nuclei of the cranial nerves. Characteristic are movement deficits, a compensatory head posture and the pattern of incomitancy. The secondary angle of deviation is usually larger than the primary. Combined pareses suggest a lesion in the cavernous sinus, orbital apex or a multilocular event. It is essential to rule out supranuclear disorders, especially if the motility deficit is atypical. For clarification, an individual risk assessment is recommended, paying particular attention to risk factors.

A 2020 Update on 20/20 X 2: Diplopia after Inadvertent Strabismus Surgery Complications

ABSTRACT The goals of successful strabismus surgery include the optimization of binocular potential through the establishment, reestablishment, or improvement of ocular alignment leading to a reduction or resolution of diplopia, as well as an improvement of compensatory head position or cosmesis. Fortunately, the incidence of new postoperative diplopia in patients without diplopia prior to strabismus surgery is extremely uncommon (less than 2%). Alternatively in a patient with preoperative diplopia that persists postoperatively, it is important to establish whether the diplopia is unchanged, increased, or of the same magnitude but shifted to a more disruptive position of gaze. During preoperative planning, the surgeon tries to anticipate and thus avoid postoperative diplopia. If the postoperative diplopia is unexpected, then a dispassionate evaluation of the outcome to identify planning, mechanical, or other factors is necessitated. These factors will be explored below systematically in the preoperative, intraoperative, and postoperative phases.

Ideal Nasal Radix Position in Fluctuating Facial Asymmetry.

Augmentation rhinoplasty had become increasingly popular among Asians. Failure to recognize nasal deviation before surgery may engender unsatisfactory outcomes because the deviation becomes prominently visible after surgery due to the central position of the nose. Ideal nasal radix positioning has yet to be addressed. The head position affects facial asymmetry judgements; however, its effect on rhinoplasty has never been studied. This study determined the ideal nasal radix position in facial fluctuating asymmetry and investigated the effects of the natural head position (NHP) on nasal deviation perceptions. A survey was conducted to compare different head and nasal radix horizontal positions using images of patients who underwent augmentation rhinoplasty. Images were retouched using editing software to adjust the head and nasal radix positions. The survey was performed using questionnaires involving 3 plastic surgeons and 3 laypersons, who were asked to determine the presence of nasal deviation and select the ideal nasal radix position among the retouched images. Twenty patients who underwent primary rhinoplasty were included in this study. The recognition of nasal deviation was significantly higher in the NHP than in the compensatory head position. The surgeons and the laypersons considered the midsagittal line the most appropriate position of the nasal radix. Facial analysis for augmentation rhinoplasty should be performed with the patient's head in the NHP to prevent nasal deviation masking. The preferred nasal radix position in facial fluctuating asymmetry is the midsagittal line.Level of Evidence: Level V, descriptive study.

Surgical treatment of a patient with congenital nystagmus with compensatory head posture: A case report

The correction of compensatory head posture in a congenital nystagmus involves surgical treatment that includes recession and resection of extraocular muscles to move the eccentric null zone to a primary position.&#x0D; A 39-year-old patient presented with an impaired visual acuity and nystagmus that was present since childhood. She had a left head turn with permanent neck pain. At the examination, best corrected visual acuity was 0.4 in both eyes with her glasses. Correction in the right eye was -6.50-1.50/180° and in the left eye -5.50-2.50/180°. Measured objective and subjective angles of squint were +4°, fusion from -3° to +29°, with the presence of stereo vision. During the cover test the nystagmus was present and it enhanced while covering the eye. Ocular motility was not limited. Fundus examination revealed myopic changes in both eyes. Prisms were prescribed, which were well tolerated by the patient. Also, no apparent head turn was noticed while wearing the prisms.&#x0D; Nine months later, the patient underwent a Kestenbaum procedure. Retroposition of the lateral rectus muscle with resection of the medial rectus muscle in the right eye and retroposition of the medial rectus muscle with resection of the lateral rectus muscle in the left eye were performed. After the procedure nystagmus dampened the most in the minimal left position, the head was in a straight position. Two years after the procedure nystagmus dampened the most in the primary position, the head was in a straight position. Nine years after surgery and refractive correction with contact lenses, the visual acuity was 0.8-0.9p in both eyes.&#x0D; The presented case showed that adequate functional and surgical treatment led to a good morphological outcome with improved visual acuity in a patient with congenital nystagmus and a compensatory head posture even in adulthood.

Clinical efficacy of the partial rectus muscle transportation procedure for paralytic strabismus.

To analyze the clinical efficacy of the partial rectus muscle transportation (PRT) procedure for paralytic strabismus due to single rectus muscle palsy. In total, 28 patients (31 eyes) who underwent the PRT procedure for paralytic strabismus due to single rectus muscle palsy were retrospectively examined. The following data were collected pre- and postoperatively: angle of deviation in the primary position, presence of diplopia in the primary position, presence of compensatory head posture, and motility of the affected eye. The follow-up period was 6mo. Based on the preoperative and intraoperative findings, different operations were performed: 2 eyes were treated with PRT, 26 eyes were treated with PRT combined with the recession of the antagonist muscle (Am) of the paralytic rectus muscle, and 3 eyes were treated with PRT along with the recession of the Am and the yoke muscle (Ym). On the first day after the operation, 24 patients were found to be orthophoric in the primary position, without diplopia or abnormal head posture. Moreover, 2 patients with monocular lateral rectus muscle palsy had mild overcorrection to 5 prism diopters (PD) and 8 PD, respectively, whereas 2 patients with binocular lateral rectus muscle palsy had mild undercorrection to 8 PD and 10 PD, respectively. During the 6-month follow-up period, the mean deviation was rectified from 96.79±41.21 PD to 0.64±2.38 PD (t=12.48, P<0.001), whereas the deviations in the 2 patients with mild overcorrection were corrected to orthotropia. The mean preoperative limitation of motility improved from -4.55±0.51 to -2.65±0.61 (t=-15.13, P<0.001) after 6mo postoperatively. PRT is an effective treatment for complete paralytic strabismus due to single rectus muscle palsy, and can achieve stable clinical efficacy.

Clinical Manifestations, Diagnosis, and Surgery of Inferior Oblique Muscle Ectopia.

Objectives To summarize the clinical manifestations, diagnosis, treatment, and prognosis for inferior oblique muscle ectopia (IO-E). Subjects and Methods. Patients diagnosed with IO-E during strabismus surgery from March 2017 to September 2018 were included in this retrospective, cross-sectional study. All patients received preoperative Krimsky test, synoptophore, cycloplegia refraction, fundus torsion, and other strabismus-related specific tests. The anatomic variations of IO-E were always discovered during surgical procedure. Postoperative eye position and binocular visual function (BVF) were all reviewed in early days after operation. Results A total of 7 patients were enrolled in this study with an average age of 6.4 ± 3.8 yrs. They all presented with significant exotropia and unilateral (or bilateral) overelevation in adduction (OEA). No compensatory head position was detected. Some of them had vertical deviation, V pattern, or excyclotropia, which were indicated by fundus torsion. Monocular or binocular IO-E was distinguished during the surgery, and it could be classified into two types according to its anatomic features. In surgery, the ectopic IO muscle bundle was restored, and different IO weakening methods were employed. Meanwhile, the horizontal deviation was also corrected according to the preoperative examination. Eyes of all patients were properly aligned in the primary position after surgery. Varying degrees of BVF appeared in 3 cases. Conclusions IO-E is a rare congenital dysplasia variation of the extraocular muscle, which could appear as inferior oblique overaction. It is difficult to diagnose before surgery, and weakening the overactive ectopic inferior oblique was required for better prognosis if this condition was confirmed during surgery.

The effects of simultaneous operation on dissociated vertical deviation with horizontal and torsional strabismus.

To investigate the therapeutic effects of simultaneous horizontal and vertical operations on dissociated vertical deviation (DVD) associated with other deviations. Forty-five cases of DVD with horizontal and torsional strabismus underwent combined operation were collected retrospectively. All clinical records were analyzed. All patients were followed up for 6 to 24mo. Wilcoxon signed-ranks test was performed to evaluate the changes of vertical and horizontal deviation. χ 2 test was used to evaluate the changes of binocular visual function. Forty-five cases included 36 patients with intermittent exotropia and binocular inferior oblique overaction (IOOA), 5 patients with concomitant esotropia and binocular IOOA, 4 patients with intermittent exotropia and monocular superior oblique palsy. The superior rectus recession (SRR) combined with horizontal rectus recession and the myectomy of inferior oblique or anterior transposition were operated simultaneously to correct all types of strabismus. There were 43 cases who achieved normal eye position in vertical direction, while 2 cases were with undercorrection of 5Δ to 6Δ. In patients with horizontal strabismus, 2 cases of exotropia were with overcorrection of 6Δ to 8Δ, 1 case of esotropia was with undercorrection of 6Δ, and 1 case of monocular superior oblique palsy with compensatory head posture was not significantly improved. The binocular visual function of most patients recovered after operation. The difference of the binocular visual function and eye position were significant compared with that before operation (P<0.05). The simultaneous operation on DVD with horizontal and torsional strabismus is successful.

Study of clinico-etiological profile of patients with paralytic and restrictive strabismus

Incomitant strabismus typically results in intractable diplopia, blepharoptosis, ocular motility disturbance, disturbance in pupil reaction and an unacceptable compensatory head or face posture. A complete clinico etiological profile is necessary for identifying the underlying risk factors and etiology pertaining to paralytic and restrictive strabismus which is imperative in prevention , early detection, managing the etiology and timely recovery in these patients.To study the clinico-etiological profile of patients with paralytic and restrictive strabismus in a tertiary eye hospital. Patients reporting to a tertiary eye hospital in north India and diagnosed with paralytic and restrictive strabismus, over a period of one year , were enrolled in the present study . Patients were subjected to detailed ocular examination and evaluated for ocular motility or related disorders. This included detailed clinical history, ophthalmic examination, orthoptic workup , sensory evaluation, diplopia charting, Hess charting, slit lamp examination and fundus examination . In patients of suspected restricted strabismus, forced duction test was performed. Relevant systemic investigations including blood pressure , blood sugar and lipid profile were carried out . M.R.I orbit was done in every patient. Neuroimaging was advised in those patients where indicated. 48 patients were diagnosed with incomitant strabismus and enrolled in the study. 81.3%were of paralytic strabismus while 18.8 % were of restrictive strabismus. In the group of paralytic strabismus, 43.8 % patients had sixth nerve palsy , 27.1% patients had third nerve palsy , 6.3% patients had fourth nerve palsy and combined nerve palsy patients were 4.2%. Analysing the etiology, out of total patients of paralytic strabismus, 48.7% of cases were idiopathic, 25.6% were post traumatic, 15.4% were due to microvascular causes , 5.1% of cases were due to intracranial anomalies and rest 5.1% were due to inflammatory causes. In restrictive strabismus group, 66.7% were congenital and rest 33.3% were acquired. Our study has reflected the prevalence, distribution , etiological and clinical profile of patients presenting with incomitant strabismus . It is helpful for ophthalmologists and other physicians in guiding diagnosis and evaluation and is useful for proper and timely intervention and timely recovery in these patients.

Disorders of oblique muscles in horizontal strabismus

Horizontal strabismus, the most common type of strabismus, can be complicated by the disorder of inferior oblique muscle or superior oblique muscle. It may cause problems such as compensatory head posture, vertical diplopia, torsional diplopia, and abnormal binocular fusion. In horizontal strabismus cases, the disorder of oblique muscles should be recognized, and appropriate surgical methods should be chosen, so that the best postoperative ortho and binocular vision could be obtained. (Chin J Ophthalmol, 2020, 56: 171-175).

Trochlear Nerve Palsy: A Review of Etiology, Incidence, Diagnostic Methods, and Treatment Alternatives

Trochlear nerve palsy is the most common palsy among the other cranial nerve palsies. It causes superior oblique muscle palsy which presents with diplopia and the compensatory head position. Several diverse surgical alternatives are available for both congenital and acquired, superior oblique palsy. Each patient should be extensively evaluated to perform a correct operation with a high success rate. In this review etiologic factors, incidence, clinical findings and different treatment methods of superior oblique muscle palsy is presented.