Head Tilt Test Research Articles

Mechanisms for Positive Bielschowsky Head Tilt Testing in Horizontal Strabismus

ABSTRACT Purpose To elucidate the induced effects of horizontal strabismus on the Bielschowsky Head Tilt Test (BHTT). Design Prospective clinical study. Methods Prospective analysis of BHTT testing in 85 patients with exotropia and 71 patients with esotropia who were examined in a strabismus clinic. Results Eighty-four of 85 patients with exotropia (98.82%) showed a positive BHTT with an induced hyperdeviation on the side of the tilt (to both sides in 67% and to one side in 32%). Fifty-seven of 71 patients with esotropia (80.2%) showed a positive BHTT with an induced hypodeviation on the side of the tilt (to both sides in 57.7% and to one side in 22.5%). These induced vertical deviations were greater in patients with larger horizontal deviations and in those with constant rather than intermittent deviations; however, they were not influenced by the presence or absence of associated primary oblique muscle overaction. Conclusions Exotropia and esotropia produce hyperdeviations during BHTT testing, with a hyperdeviation on the side of the tilt observed in patients with exotropia, and hypotropia on the side of the tilt observed in patients with esotropia. These diametrical results are not attributable to any preexistent alteration of neurologic output inherent to these two forms of horizontal strabismus or to associated torsion. Rather, they arise directly from the altered anatomical positions of the two eyes, which cause the eyes to approximate their visual axes more closely to the vertical rectus muscles (in exotropia) and the oblique muscles (in esotropia), enabling the vertical actions of specific cyclovertical muscles to predominate in response to altered utricular output generated by the BHTT.

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.

Comparison of head tilt test between sagging eye syndrome and acquired unilateral trochlear nerve palsy

PurposeTo investigate the distinction between sagging eye syndrome (SES group) and acquired unilateral trochlear nerve palsy (Trochlear group) in the Bielschowsky head tilt test (BHTT).MethodsFifteen patients in the SES group (mean age 74.6 ± 5.2 years) and 14 patients in the Trochlear group (55.2 ± 15.9 years) visited the Department of Ophthalmology, Hyogo Medical University Hospital between November 2016 and October 2022 for treatment of their diplopia. Eye position was measured with the alternate prism cover test, and values for fixation of the dominant eye, or unaffected eye, were used. Cyclodeviation was measured with the synoptophore and the Glaucoma Module Premium Edition of the SPECTRALIS optical coherence tomography. In the BHTT, eye position was measured in three head postures: primary position (PP), head tilt to the side with hypertropia (Hyper), and head tilt to the side with hypotropia (Hypo). The differences in vertical deviation between PP and Hyper (Hyper − PP), PP and Hypo (PP − Hypo) and Hyper − Hypo were measured and compared.ResultsVertical deviation in primary position was 7.3 ± 4.5 PD in the SES group and significantly larger (17.1 ± 8.4 PD) in the Trochlear group (p = 0.002). The vertical deviation in Hyper was significantly larger in the Trochlear group with 7.7 ± 4.7 PD and 22.1 ± 9.4 PD, respectively (p < 0.001), whereas the that in Hypo was not significantly different between the two groups with 6.5 ± 3.4 PD and 8.4 ± 6.6 PD, respectively (p = 0.725). The SES group showed no significant difference according to the 3 head postures (p = 0.311), while the Trochlear group showed a significantly different with smaller mean values in vertical deviation in Hypo (p < 0.001). The difference in the vertical deviation for the 3 head postures was the largest in Hyper − Hypo (1.7 ± 2.1 PD and 13.6 ± 7.1 PD, respectively), and the accuracy of SES was at the cutoff value of 6 PD, and it was considered not to be SES if the value was 6PD or higher. The accuracy of SES determination was 100% sensitivity and 100% specificity, and the area under the curve was 1.0.ConclusionThe difference in Hyper − Hypo in the BHTT may be the most useful index in differentiating SES from acquired unilateral trochlear nerve palsy; if the difference was more than 6 PD, the probability of SES was very low.

How Lingering Fusional Adaptation Influences the Bielschowsky Head Tilt Test in Superior Oblique Paresis.

The lack of a positive Bielschowsky head tilt test (BHTT) is commonly seen as an indicator that superior oblique paresis (SOP) is not present. This study investigated the influence of fusion on the BHTT in unilateral SOP. We analyzed vertical fusional vergence using our eye-tracking haploscope and the value of BHTT difference (BHTTD) in 11 patients who were diagnosed with congenital unilateral SOP and able to fuse. Patients used one of three different mechanisms of vertical vergence to achieve fusion. The three fusional mechanisms were associated with a significantly different BHTTD (p < 0.05). Seven of the eleven patients used vertical recti-mediated fusion and had a mean BHTTD ± SD of 21.7 ± 6.3 prism diopters (PD). Three of these patients whom we measured after a patch test for at least 30 min showed a decreased BHTTD (12.7 ± 3.8 PD). Three of the eleven patients used a mixed (oblique/rectus) fusional mechanism and had a mean BHTTD ± SD of 9.3 ± 8.6 PD. Of these patients, the one whom we measured after patching showed an increase of 11 PD in BHTTD. The remaining patient used oblique muscle-mediated fusion and had a BHTTD of only 3 PD that increased to 21 PD after patching. One explanation for this BHTT behavior in the latter patient involves lingering vergence adaptation of the "paretic" superior oblique muscle (SOM) and contralateral inferior oblique muscle, which makes these muscles more effective when activated, as is the case on ipsilateral head tilt (part of the ocular counter-roll mechanism), lessening the expected increase in hyperdeviation. Similarly, in our patients with mixed fusion, the vergence-adapted "paretic" SOM and contralateral superior rectus muscle are activated on ipsilateral and contralateral tilt, respectively, lessening the hyperdeviation in both directions. In the other seven patients, however, the vergence-adapted ipsilateral inferior rectus muscle and contralateral superior rectus muscle are activated on contralateral tilt, accentuating the BHTTD. Depending upon the specific muscles used for vertical fusion, the BHTTD is decreased or increased. The presence of a large BHTTD points to lingering or persisting fusional tonus involving the vertical rectus muscles. The lack of a positive BHTT does not rule out the diagnosis of SOP, but rather may be caused by lingering or persevering fusional tonus involving the oblique muscles. Performing the BHTT after a patch test for a minimum of 30 minutes may be necessary to reveal the BHTTD, supporting the diagnosis of SOP.

Safety Aspects of DIMS Technology Glasses, Fixation as a Marker for Amblyopia, Bielschowsky Head Tilt Test in Superior Oblique Paresis and Successful Late Topical Treatment of Orbital Infantile Hemangioma

Safety Aspects of DIMS Technology Glasses, Fixation as a Marker for Amblyopia, Bielschowsky Head Tilt Test in Superior Oblique Paresis and Successful Late Topical Treatment of Orbital Infantile Hemangioma

Masquerading Superior Oblique Palsy

We evaluated patients with hypertropia compatible with a diagnosis of superior oblique (SO) palsy to ascertain whether the 3-step test (3ST) can distinguish SO atrophy characteristic of trochlear nerve pathology from masquerading conditions. Prospective cross-sectional study. In an academic practice, we performed quasi-coronal plane, surface coil magnetic resonance imaging in 83 patients clinically diagnosed with SO palsy. We evaluated alignment, SO cross-sectional area, SO contractility, and rectus muscle pulley positions. A total of 57 patients with mean age 39 years (SD = 21 years) had unilateral SO palsy manifested by SO atrophy (22 congenital and 35 acquired). There was normal SO size in 26 patients with an average age of 39 years (SD =16 years) considered masquerades (8 congenital and 18 acquired). Maximum palsied SO cross-section averaged 9.5 ± 3.8 mm2, less than 18.4 ± 3.9 mm2 contralaterally (P < 10-24). In masquerades, maximum hypertropic SO cross-section was 20.7 ± 3.1 mm2, which was not different from the hypotropic SO or the contralesional muscle in SO palsy. Head tilt testing in masquerades was indistinguishable from SO palsy. In SO palsy, central hypertropia averaged 13.2 ± 9.4Δ, increasing to 21.1 ± 14.0Δ in ipsilateral tilt, and decreasing to 4.3 ± 5.3Δ in contralateral tilt. In masquerades, central hypertropia averaged 13.1 ± 8.7Δ, and was 17.7 ± 11.1Δ in ipsilateral and decreasing to 4.9 ± 5.1Δ in contralateral tilt. Upright hypertropia was larger at 17.7 ± 9.9Δ in congenital than 12.0 ± 8.4Δ in acquired SO palsy (P = 0025) but was indistinguishable from congenital masquerades. Contractile change in SO cross-section was bilaterally similar in masquerades. Relevant coordinates of rectus pulleys were similar bilaterally in masquerades. The 3ST pattern characteristic of unilateral SO palsy may be mimicked in all respects by masquerades.

Cranial nerve IV palsy after mild head trauma: a rare image.

Mild traumatic brain injury is characterized by a Glasgow coma scale GCS between 13 and 15. It is a frequent pathology in our country because of the increasing number of circulation accidents. Trauma-induced superior oblique palsy usually results from contusion or avulsion of the trochlear nerve. Severe craniocerebral trauma is often associated with the former mechanism, whereas more minor closed-head injuries can decompensate a congenital phoria. We report a patient who developed an isolated trochlear nerve palsy following minor head trauma. Our 53 years-old patient without significant past medical history was victim of a traffic accident. He presented with a complaint of diplopia following head trauma the week prior. He lost consciousness for less than 1 minute. He noticed diplopia immediately upon awakening, but had no other neurologic symptoms. He presented to our emergency department for evaluation. Computed brain tomography (CT) performed did not show any orbital fractures. Ocular exam revealed mild to moderate infraduction deficit and supraduction excess in adduction of the left eye. Left head tilt test was negative. We finally concluded that our patient had a trochlear nerve palsy following the brain trauma. Further Magnetic Resonance Imaging (MRI) revealed an unsuspected tentorial vascular malformation that was compressing the trochlear nerve in its subarachnoid course. In the absence of other features that support decompensation of a congenital trochlear nerve palsy, compressive lesions should be sought in case of fourth cranial nerve palsy following head trauma.

Vertical Strabismus and Positive Bielschowsky Head-Tilt Test: Atypical Presentation of a Maxillary Mucocele

AbstractTest of skew has become a cornerstone in the approach of a patient with vestibular symptoms but a detected vertical misalignment may be caused by an oculomotor disturbance and not a skew deviation. We report the case of an elderly patient with a 1-month history of dizziness and visual disturbance that revealed on bedside examination a spontaneous left head-tilt and a pathologic alternate cover test, with right eye hypertropia and excyclotorsion, worse with right head-tilt. Dizziness was assumed to have a visual origin with unrecognized binocular diplopia, caused by an acquired right eye superior oblique muscle palsy. However, imaging revealed a right maxillary mucocele that eroded the orbit floor into the orbit. The change of the intraorbital component of the maxillary fluid-filled mass with head-tilt through a dehiscent orbital floor may explain the findings of vertical strabismus and positive Bielschowsky head-tilt test in this case. Endoscopic treatment improved symptoms and findings.

Traumatic bilateral fourth nerve palsy: Double vision induced by downward gaze after head injury.

Clinicians should be alert to traumatic fourth nerve palsy in patients with double vision after head injury. In most cases with traumatic fourth nerve palsy, the imaging tests fail to show abnormal findings. In the cases of bilateral superior oblique paresis, the sensitivity of Bielschowsky head-tilt test is 40%.

Diagnosis and surgical management of isolated inferior oblique palsy.

To describe the etiology, clinical characteristics, surgical options and surgical outcomes of isolated inferior oblique palsy (IOP). A retrospective review was performed on patients with isolated IOP who were seen between January 2010 and June 2017. The following clinical data were obtained from the patients' charts: visual acuity, ocular alignment, ocular motility, cyclotorsion, stereoacuity, Parks three-step test, surgical methods, surgical outcomes and complications. Surgical success was defined as horizontal deviation ≤10 prism diopters (PD) and a vertical deviation ≤5 PD in primary gaze at both near and distant vision as assessed at last follow-up. The records from a total of 18 patients (8 males and 10 females) with an average age of 27.56y were included in this study. The right eye was affected in 11 patients, the left in 6 patients and both eyes in 1 patient. Twelve cases (66.7%) were congenital and 6 (33.3%) were acquired IOP. The 6 acquired cases involved 2 resulting from orbital trauma/surgery, 2 from midbrain microvascular ischemia, 1 from myasthenia gravis and 1 of unknown etiology. Strabismus surgery was performed in 13 cases. Surgical techniques included weakening of superior oblique and vertical rectus recession and resection. After a mean follow-up of 15.11mo, the corrected vertical deviation in primary position was 19.92±8.52 PD (P=0.000) and the corrected horizontal deviation was 14.31±12.68 PD (P=0.002). The surgical success rate was 61.5% and no surgical complications were present. Isolated IOP represents a rare condition, with most cases (66.7%) involving a congenital basis. The acquired cases included vascular, orbital trauma/surgery and myasthenia gravis. Weakening of the ipsilateral superior oblique muscle and/or contralateral superior rectus recession often resulted in favorable surgical outcomes with a surgical success rate of 61.5%.

Isolated Unilateral Strabismus Sursoadductorius (Congenital Trochlear Palsy) with and without Hypotrophia of the Superior Oblique Muscle-Orthoptic Differences in Adulthood

The clinical feature of unilateral decompensating strabismus sursoadductorius (dSSA; often called congenital superior oblique palsy, CSOP) is not an etiologically uniform entity. Hypotrophy of the superior oblique muscle (HMOS) is a frequent and immediate cause of dSSA/CSOP. In this study, clinical characteristics of dSSA/CSOP with and without HMOS are compared. Twenty-five consecutive patients (age 14 - 69 years; median 43 years) were included in this study, 14 with 3T MRI-proven HMOS (group 1) and 11 without HMOS (group 2). HMOS was defined as a reduction of the medio-lateral (ML) as well as based on ML and cranio-caudal (CC) diameter calculated area = (ML · CC/4) · π of the affected superior oblique muscle (SOM) < 80% in comparison to the contralateral SOM (measured on the single coronal image on which the muscle has its greatest extent). The two groups were compared in terms of head tilt, cyclo- and vertical deviation and the Bielschowsky head tilt test. Patients were classified according the Knapp's classification. Both the incidence of head tilt with 14/14 vs. 5/11 (χ2 = 0.003) and its degree: 11.1 ± 4.5° vs. 3.2 ± 4.1° (p < 0.001) was higher in group 1 than in group 2, as well as the Bielschowsky head tilt test: 9.3 ± 4.3° vs. 3.8 ± 4.9° (p = 0.008). The average amount of hypertropia was larger in group 1 than in group 2 during adduction: 16.7 ± 5.3° vs. 9.3 ± 3.4° (p < 0.001) as well as during adduction and downgaze of the affected eye: 14.6 ± 7.1 vs. 7.2 ± 3.7° (p = 0.03). In the sagittal plane, the increase of vertical deviation was larger in group 1 than in group 2: 2.8 ± 7.8 vs. - 2.4 ± 4.2 (p = 0.04); the excyclodeviation was larger in group 1 in all three planes (sagittal plane, adduction and abduction) in comparison to group 2: 1.3 ± 4.1 vs. - 2.9 ± 2.8 (p = 0.006), 2.4 ± 5.2 vs. - 2.2 ± 2.9 (p = 0.01), 0.5 ± 3.8 vs. - 2.7 ± 3.9 (p = 0.05). Knapp's class II was found in 6 of 15 patients in group 1 and only in this patient group (χ2 = 0.03). In both groups, the vertical deviation showed a great dispersion. In patients without HMOS (group 2), vertical deviation in adduction did not exceed 15°. Patients with HMOS (group 1) do not show the typical features of a later acquired trochlear palsy due to an early developed compensating innervation. A vertical deviation in adduction of more than 15°, increasing excyclodeviation towards downgaze in all three planes (sagittal plane, adduction and abduction) and Knapp's class II are relatively reliable predictors of a hypoplasia of the SOM. An internationally uniform term for this group of patients, such as superior oblique weakness or superior oblique hypotrophy, would be desirable.

Does Decreased Static Ocular Counter Rolling Account for Bielschowsky Head Tilt Test in Unilateral Superior Oblique Palsy?

To understand the relationship of static ocular counter rolling (s-OCR) and clinical manifestations in acquired unilateral superior oblique palsy subjects during the Bielschowsky head tilt test. Nineteen subjects that were diagnosed with acquired unilateral superior oblique palsy were included. Fundus photographs were obtained at different head tilt angles to evaluate static ocular counter rolling using a fundus camera with a cervical range of motion device. Using a graphics editing program, we calculated s-OCR from fundus photography. The incycloductional s-OCR (OCR-I) in the paretic eye was significantly smaller than the OCR-I in the fellow eye (P = 0.02, <0.001, 0.002 for 10°, 20°, and 30°, respectively, paired t-tests). In contrast, the excycloductional s-OCR (OCR-E) showed no significant difference between the paretic eye and the fellow eye for all angles. There was a significantly positive correlation between the amplitude of OCR-I in the paretic eye and the degree of hypertropia on ipsilesional head tilt (ρ = 0.612, 0.679, 0.474, P = 0.02, 0.002, 0.07 for 10°, 20°, and 30° respectively, Spearman's correlation). The amplitude of OCR-I in the paretic eye also showed a positive correlation with head tilt test difference, which is the degree of hyperdeviation difference between ipsilesional and contralesional head tilts (ρ = 0.445, 0.694, 0.579, P = 0.09, 0.002, 0.024 for 10°, 20°, and 30° respectively, Spearman's correlation). In unilateral SOP, OCR-I in the paretic eye was smaller than that in the fellow eye, and this was positively associated with the degree of hypertropia during ipsilesional head tilting, as well as the head tilt test difference.

The effect of superior oblique tucking on the Bielschowsky head tilt test

To investigate the effect of superior oblique tucking on the Bielschowsky head tilt test. A retrospective analysis of 22 patients with congenital unilateral superior oblique palsy, who underwent tucking of the superior oblique tendon in Tianjin Eye Hospital, depending on vertical deviation in the primary position, ocular motility, objective cyclotorsion and abnormal head posture. Bielschowsky head tilt test was evaluated quantitatively by the prism cover test. Α positive Bielschowsky head tilt test was defined as one in which the vertical deviation when the head tilt to the side of the paresis was at least 5. 0(△) greater than that on tilt to the uninvolved side. The follow-up period ranged from 3 to 12 months (mean 4.6 months). Kolmogorov-Smirnov (K-S), Rank sum test and Spearman correlation analysis statistical methods were used in this study. All patients had vertical deviation and significant abnormal head posture before operation. After the procedure of superior oblique tucking,vertical deviation and symptom of unacceptable abnormal head posture were ameliorated or disappeared. OBJECTIVE torsion was 15.62°±7.36° before the surgery, 9.91°±10.09°1d after the surgery and 11.25°±9.17°at the last follow-up visit, respectively (P<0.05). We found that there were positive correlations between the objective cyclotorsion and the vertical deviation difference value between the paralyzed side and uninvolved side at 1 d after the surgery and last follow-up visit(P<0.05). The vertical deviation of the paresised eye when the head tilted to the side of paresis side and uninvolved side difference were 5.00(△)-17.00(△), average 8.68(△)±3.23(△), 1.00(△)-8.00(△),average 3.36(△)±2.01(△) and 0.00(△)-14.00(△),average 3.77(△)±3.01(△), preoperatively, 1d after the surgery and at the last follow-up visit respectively. Using Rank sum test, the pre-and postoperative difference was statistically significant (Z=-4.64, P<0.01). A positive Bielschowsky head tilt test was found in all cases preoperatively. The results of Bielschowsky tilt test was still positive in 5 cases and negative in 17 cases (77.3%). In most cases with unilateral superior oblique paresis, the results of Bielschowsky tilt test became negative after superior oblique tucking. The long-standing results is worthy of observation. (Chin J Ophthalmol, 2016, 52: 589-595).

Neck muscle asymmetry in ocular torticollis with positive head tilt test

Neck muscle asymmetry in ocular torticollis with positive head tilt test

Intermittent exotropia with a positive Bielschowsky head-tilt test.

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

The influence of lingering fusional adaptation on the Bielschowsky head tilt test in superior oblique paresis

PurposeTo investigate how fusion influences the Bielschowsky head tilt test (BHTT) in unilateral superior oblique paresis (SOP).MethodsIn eight fusing patients, we correlated haploscopic‐determined fusion mechanisms with BHTT differences (BHTTD).ResultsFive patients used the vertical recti for vertical fusional vergence and had a mean±SD BHTTD of 22 ± 8PD. After a 30‐minute patch test one of those, in whom the test was performed, showed a decrease of 10PD. Two patients used the “paretic” superior oblique muscle (SOM) and the contralateral superior rectus muscle (SRM) to fuse, and had a mean ± SD BHTTD of 6 ± 8PD. The BHTTD of one, in whom a patch test was performed, increased by 11PD. The remaining patient used the “paretic” SOM and contralateral inferior oblique muscle (IOM) to fuse, and had a BHTTD of only 3PD, increasing to 21PD after patching.One explanation for this behavior in the last patient involves lingering vergence adaptation of the “paretic” SOM and contralateral IOM, which makes these muscles more effective when activated on ipsilateral head tilt, lessening the expected increase in hyperdeviation. Similarly, in our patients with oblique/rectus‐mediated fusion, the vergence‐adapted “paretic” SOM and contralateral SRM are activated on ipsilateral and contralateral tilt respectively, lessening the hyperdeviation in both directions. In the other five patients, however, the vergence‐adapted ipsilateral IRM and contralateral SRM are activated on contralateral tilt, accentuating the BHTTD.ConclusionsFusion influences the BHTTD, either decreasing or increasing it depending on the particular muscles used for fusion. The absence of a positive BHTT should not be relied upon to rule out the diagnosis of SOP. In suspected SOP patients with fusion, performing the BHTT after a patch test may be necessary to bring out the BHTTD supporting the diagnosis.

The distinctive vertical heterophoria of dyslexics.

In this study, we looked for the presence of vertical heterophoria (VH) in 42 dyslexic children (22 males and 20 females) aged 118.5±12.9 months who were compared with a control group of 22 nondyslexic children (eleven males and eleven females) aged 112±9.8 months. Dyslexics presented a low-level (always <1 prism diopter) VH combined with torsion. This oculomotor feature clearly separates the dyslexic group from the normal readers group. It is independent of the type of dyslexia. The essential feature of this VH is a lability that appears during specific stimulation of sensory receptors involved in postural regulation. This lability is demonstrated using a vertical Maddox test conducted under very specific conditions in which postural sensors are successively stimulated in a predetermined order. A quantitative variation in this VH may be seen during the Bielchowsky Head Tilt Test, which reveals hypertonia of the lower or upper oblique muscles. Vertical orthophoria can be achieved by placing low-power prisms asymmetrically within the direction of action of the superior or inferior oblique muscles. The selection of power and axis is not only guided by elements of the eye examination but also from observation of postural muscle tone. All these elements suggest that the VH could be of postural origin and somehow related to the vertical action of the oblique muscles. VH and torsion are not harmful per se. There is no statistical relationship between their level and the various parameters used to assess the reading skills of dyslexic children. VH and torsion could be a clinical marker of global proprioceptive dysfunction responsible for high-level multisensory disturbances secondary to poor spatial localization of visual and auditory information. This dysfunction might also explain the motor disorders concomitant to dyslexia.

Orthoptic Sequelae Following Conservative Management of Pure Blowout Orbital Fractures: Anecdotal or Clinically Relevant?

The aim of this study was to prospectively assess the prevalence of orthoptic anomalies following conservative management of pure blowout orbital fractures and to evaluate their clinical relevance. Clinical and radiologic data of patients with unilateral conservatively managed pure blowout orbital fractures with a minimum follow-up of 6 months were reviewed. Eligible patients were contacted and invited to undergo an extended ophthalmologic examination as follows: distance and near visual acuities, Hertel exophthalmometry, corneal light reflex (Hirschberg test), ductions and versions in the 6 cardinal fields of gaze, eye deviation with prisms and alternate cover test in all of the 9-gaze directions with Maddox rod, degrees of incyclo/excyclotorsion with right and left eye fixation, horizontal and vertical deviation with Hess-Weiss coordimetry, degree of horizontal/vertical and incyclo/excyclotorsion deviation with Harms wall deviometry, and vertical deviation with Bielschowsky head-tilt test. Of the 69 patients contacted, 49 declined to participate given that they were asymptomatic. Twenty patients agreed to undergo the examination. One patient complained of minimal double vision limited to the extreme downgaze. Four patients had asymptomatic ocular motility disturbances limited to the extreme gaze. Seven patients had asymptomatic horizontal heterophoria. These disturbances did not interfere with daily or professional activities in any of the patients. The current study demonstrated that conservative management of pure orbital blowout fractures can result in orthoptic anomalies. These sequelae were restricted to a very limited portion of the binocular field of the vision and were not found to be clinically relevant.

Alternating IV Nerve Palsy and Ptosis as a First Sign of Childhood Ocular Myasthenia Gravis

A previously healthy 5-year-old girl was referred because of sudden-onset diplopia. Her examination demonstrated moderate right ptosis, left inferior oblique overaction and superior oblique underaction, and a positive Bielschowsky head tilt test to the left. This suggested a left fourth nerve palsy, but the right ptosis remained undefined (Figure). Ophthalmic and neurological examination and cranial magnetic resonance imaging were otherwise normal. Ten days later, a right fourth nerve palsy with a right ptosis and left adduction deficit was evident.

Superior oblique tucking for treatment of superior oblique palsy.

To investigate the efficacy and safety of isolated superior oblique tucking in the treatment of congenital superior oblique palsy. Twenty-one patients with unilateral congenital superior oblique palsy and lax superior oblique tendon underwent isolated superior oblique tucking and retrospective analysis of the amount of tucking procedure, preoperative and postoperative vertical deviation in the primary position and reading position, abnormal head posture, ocular motility, and corrected objective torsion. Patients were evaluated before and 6 to 12 months after surgery. The average vertical deviation in the primary position was 10.9 ± 3.3 prism diopters (PD) before surgery and 1.5 ± 2.6 PD after surgery (n = 21, P < .05). The average vertical deviation in the reading position was 15.6 ± 3.6 PD before surgery and 2.6 ± 3.1 PD after surgery (P < .05). The average corrected vertical deviation was 9.9 ± 3.2 PD in the primary position and 13.0 ± 3.4 PD in the reading position (P < .05). The amount of tucking ranged from 5 to 12 mm (mean: 8.3 ± 2.3 mm), which was not related to the corrected vertical deviation in the primary and reading positions, the preoperative vertical deviation in the reading position, or the corrected objective torsion. After surgery, all patients had head posture that was normal or less than 5°. Unremarkable superior oblique underaction and negative head tilt test were found in all patients after surgery. All patients had mild Brown syndrome after surgery, but none were symptomatic. Isolated superior oblique tucking is an efficient and safe procedure for treatment of superior oblique palsy with hyperdeviation less than 15 PD in the primary position and remarkable superior oblique underaction. The superior oblique forced duction test was the most important criterion for planning surgery.