Teprotumumab for Thyroid Eye Disease-related Strabismus.

PURPOSE: To assess and quantify teprotumumab's effect on thyroid eye disease-related strabismus by change in measured horizontal and vertical deviations and change in extraocular motility. METHODS: We reviewed a series of patients with thyroid eye disease-related strabismus treated with teprotumumab. Exclusion criteria included age under 18 years, strabismus of alternate etiology, or thyroid eye disease-related reconstructive surgery during the treatment course. Primary outcomes were absolute (prism diopters) and relative (%) differences in horizontal and vertical deviations in primary position at distance, as well as change in ductions of the more affected eye. Secondary outcomes included incidence and timing of strabismus surgery postteprotumumab. RESULTS: Thirty-one patients were included, with mean age 63 years and thyroid eye disease duration 10 months. After teprotumumab, there was 6 prism diopters (39%) mean reduction in vertical deviation ( p < 0.001), without significant change in mean horizontal deviation ( p = 0.75). Supraduction, abduction, adduction, and infraduction significantly improved in the more restricted eye ( p < 0.01, p < 0.01, p = 0.04, and p = 0.01, respectively). Thirty-five percent of patients underwent strabismus surgery posttreatment, at an average 10 months after last infusion. CONCLUSIONS: Teprotumumab produced a statistically significant reduction in vertical but not horizontal strabismus angles in primary position at distance. Extraocular motility in all 4 ductions also improved. A substantial minority of patients still required strabismus surgery following teprotumumab.

Vertical Comitance of Hypertropia in Congenital and Acquired Superior Oblique Palsy.

BACKGROUND: Ivanir and Trobe have claimed that hypertropia (HT) that is greater in upgaze than downgaze, or equal to it, is characteristic of decompensated congenital superior oblique (SO) palsy and never present in ischemic, traumatic, or tumorous SO palsy. The reliability of this claim was tested in patients with SO palsy confirmed by MRI demonstration of subnormal ipsilesional SO size. METHODS: Quasi-coronal, surface coil MRI was performed in target-controlled central gaze to identify patients with a unilateral reduction in SO cross section indicative of palsy. Nine patients gave an unequivocal history or had markedly increased vertical fusional amplitudes indicative of congenital onset (mean age 38 ± 16 years, SD). Seven patients had unequivocal acquired onset (age 47 ± 14 years and symptom duration 5.4 ± 4.8 years), including 2 with demonstrated trochlear Schwannoma and 5 with onset after severe head trauma. Fifteen patients had gradually progressive onset unequivocally not congenital yet not associated with any identifiable precipitating event (age 52 ± 20 years and symptom duration 13 ± 14 years). RESULTS: Maximum SO cross section averaged 8.6 ± 3.9 mm2 in congenital palsy, not significantly different from 11.3 ± 3.5 mm2 in acquired palsy (P = 0.08) either unequivocally or progressively acquired, but significantly less than about 19 mm2 contralesionally in SO palsy (P < 10-4). Although mean central gaze HT was greater at 20.6 ± 8.0Δ in 9 cases of congenital than that in 22 acquired cases at 11.4 ± 6.8Δ (P = 0.002), HT was 8.4 ± 16.3Δ less in upgaze than downgaze in congenital SO palsy and 3.7 ± 11.2Δ less in acquired SO palsy. In congenital palsy, 33% of patients had HT greater in upgaze than downgaze while in 67% HT was greater in downgaze (by up to 42Δ). In acquired SO palsy, HT was greater in upgaze than downgaze or equal to it in 8 cases (36%, P = 0.87, X2). In acquired SO palsy, HT was greater in upgaze than downgaze in 37% and greater in downgaze than upgaze in 59% of cases. The HT was equal in upgaze and centralgaze in no congenital and 3 acquired cases of SO palsy. Trends were similar in unequivocal acquired and progressive acquired (noncongenital) SO palsy (P > 0.4). CONCLUSIONS: Hypertropia is not characteristically greater in upgaze than downgaze in congenital SO palsy proven by SO atrophy on MRI. In fact, average HT is greater in downgaze than upgaze in both acquired and congenital palsy, sometimes strikingly so in the latter. The finding of HT greater in upgaze than downgaze, or equal to it, does not reliably indicate that SO palsy is congenital, nor does maximum SO cross section.

Clinical and imaging features of congenital and acquired isolated inferior rectus muscle hypofunction.

BACKGROUND: Inferior rectus (IR) underaction may arise from various causes that are distinguishable through imaging. We investigated clinical and imaging characteristics of congenital and acquired causes of IR underaction. METHODS: Cases of IR underaction were selected from data prospectively collected in a study of orbital imaging in strabismic patients. RESULTS: Review identified 3 cases of congenital IR underaction (2 with bilateral IR aplasia and 1 with unilateral IR hypoplasia), 12 acquired cases, including 4 due to denervation (2 idiopathic, 1 after multiple strabismus surgeries, 1 after head trauma), and 8 cases of direct IR damage (5 with orbital trauma and 3 with previous surgery, including 2 sinus surgery and 1 laser blepharoplasty). Of the 23 cases, 11 adults had high-resolution magnetic resonance imaging, and 2 children had computed tomography. Imaging identified the anatomic diagnosis in congenital cases; in acquired cases, imaging helped to identify atrophy and exclude alternative orbital causes; and in direct mechanical damage, imaging clarified the mechanism of underaction, extent of IR damaged, and the degree of retained contractility. Patients with congenital IR absence or hypoplasia exhibited A pattern exotropia that was typically absent in isolated acquired denervation or direct IR damage. CONCLUSIONS: Orbital imaging demonstrates a variety of abnormalities in patients with congenital or acquired IR hypofunction, helping to clarify the underlying mechanism and guide management.

Strabismus After Ahmed Glaucoma Valve Implantation.

PURPOSE: Most reports of strabismus after glaucoma drainage device implantation study larger devices and rarely note the incidence of strabismus after Ahmed glaucoma valve (AGV) implantation. It is unknown if the pattern of strabismus is similar with smaller devices. We investigated characteristics of strabismus after AGV implantation. DESIGN: Retrospective review. METHODS: Institutional study of 732 patients at our institution undergoing AGV implantation between 2013 and 2018. Rate and characteristics of strabismus were the primary outcome; age, gender, and location of AGVs were also analyzed. RESULTS: We identified 29 patients who developed new-onset strabismus postoperatively after initial AGV implantation, for 4% incidence of strabismus. Twenty-one (72%) of these had diplopia. AGVs were implanted superotemporally in 21, superonasally in 5, inferotemporally in 1, and inferonasally in 2. Three patients were esotropic, 11 were exotropic, 4 had hypertropia, 2 had hypotropia, and 9 patients had combined horizontal/vertical strabismus (esotropia/hypotropia [n = 1] or exotropia/hypertropias [n = 8]). Exotropia was the most common type of strabismus in both the superotemporal and superonasal (60%) AGV groups. Superotemporal AGVs were more commonly associated with ipsilateral hypertropia (43%) than superonasal AGVs. Treatments included strabismus surgery (n = 14), prisms (n = 6), or an occlusive lens (n = 1). DISCUSSION: In the largest single-center series of patients undergoing initial AGV implantation, the overall incidence of postoperative strabismus was 4%. This is comparable to strabismus incidence following implantation of other types of glaucoma drainage devices, even larger devices. The possibility of this complication should be discussed with patients prior to surgery.

The Adnexal Phenotype of Sagging Eye Syndrome.

PURPOSE: The sagging eye syndrome (SES) describes a condition that presents with age-related distance esotropia, alone or in combination with cyclovertical strabismus. It has a high prevalence in those aged over age 40 years presenting with binocular diplopia. The authors aim to characterize the adnexal phenotype of those who have been diagnosed with SES. METHODS: In this case-control study, patients were recruited from a prospectively maintained clinical and imaging database. The inclusion criteria required that subjects be above the age of 18 years and have a diagnosis of age-related distance esotropia or cyclovertical strabismus due to SES. Age-matched controls were selected from a validated database of normal faces that were not affected by any medical or surgical conditions. The margin to reflex distance from the upper eyelid, margin to reflex distance to the lower eyelid, the tarsal platform show, intracanthal distance, and inferior scleral bow were measured. Differences in the measurements between patients and controls were analyzed using a 2-tailed Student t tests. RESULTS: Twenty-two patients and 22 age-matched controls (11 males and 11 females per group) were included for study. Females with SES had a significantly greater margin to reflex distance to the lower eyelid and inferior scleral bow, with a lower tarsal platform show and margin to reflex distance from the upper eyelid than controls. Male patients with SES had a significantly greater margin to reflex distance to the lower eyelid and inferior scleral bow with a significantly lower margin to reflex distance from the upper eyelid and tarsal platform show than controls. DISCUSSION: This study supports the growing body of evidence which suggests that the SES represents age-related mechanical changes in the orbit that manifest as a specific adnexal phenotype.

Prevalence of Sagging Eye Syndrome in Adults with Binocular Diplopia.

PURPOSE: Sagging eye syndrome (SES), horizontal and/or vertical strabismus caused by orbital connective tissue degeneration, was first defined 10 years ago. This study investigated SES and other causes of acquired binocular diplopia in adults presenting to a single institution since the description of SES. DESIGN: Retrospective observational case series. METHODS: Medical records were reviewed of all new patients over the age of 40 who presented to the Stein Eye Institute with binocular diplopia between January 2015 and December 2018. Clinical causes of diplopia were tabulated in patients grouped by age and sex. In patients with SES, we tabulated binocular alignment, types of treatment, and surgical outcomes. RESULTS: There were 945 patients of mean age 66.5 years, of whom 514 (54.4%) were female. The most common cause of diplopia was SES (31.4%). The 297 patients with SES were older at 71.2 years (P < 0.0001) and more predominantly female at 59.9% than other patients (52.0%; P = 0.023). The relative proportion of SES patients among all diplopic patients increased with age from 4.7% under age 50 years to 60.9% over the age of 90. Age-related distance esotropia was present in 35% and cyclovertical strabismus in 65% of cases of SES. Strabismus surgery was performed in 50% of cases of SES. Mean esotropia at distance decreased from 6.9 ± 0.7Δ preoperatively to 0.3 ± 0.3Δ postoperatively. Preoperative hypertropia decreased from 3.0 ± 0.3Δ to 0.7 ± 0.2Δ postoperatively. Surgery resolved diplopia in all cases. CONCLUSIONS: It is important to recognize that SES is a very common cause of adult binocular diplopia.

Differential Regional Stiffening of Sclera by Collagen Cross-linking.

Purpose: Corneal collagen cross-linking by ultraviolet light activation of riboflavin has been used clinically to enhance corneal stiffness. We sought to determine if cross-linking differentially affects scleral regions.Methods: Adjacent, parallel strips of sclera were cut from superolateral, superomedial, inferolateral, and inferomedial quadrants of posterior and equatorial sclera of 12 human cadaver eyes. One of each pair served as control while the other was cross-linked by immersion in 0.1% riboflavin and 365 nm exposure at 6 mW/cm2 irradiance for 30 min. Behavior of strips was characterized using a microtensile load cell. Preloaded strips were imaged using orthogonally mounted cameras and optical coherence tomography to determine specimen dimensions including cross-sectional area. Tension was measured during 0.1 mm/s constant rate elongation.Results: Young's modulus (YM), the slope of the relationship relating tensile stress to strain, was calculated at 8% strain, and increased significantly after cross-linking (P < .001). In posterior sclera, mean (± standard error of mean, SEM) YM is increased in the superolateral, superomedial, inferolateral, and inferomedial quadrants by 46 ± 15%, 32 ± 11%, 67 ± 20%, and 53 ± 11%, respectively. In equatorial sclera, YM is increased by 139 ± 43%, 68 ± 27%, 143 ± 92%, and 68 ± 14%, respectively. The YM of pooled equatorial quadrants increased significantly more than that of the pooled posterior quadrants.Conclusions: Scleral collagen cross-linking by ultraviolet activation of riboflavin differentially increases scleral YM more in the equatorial than posterior sclera, and most in the lateral, equatorial sclera. Cross-linking might be used to arrest progressive myopia or to prevent staphyloma formation.

Cross-Sectional Soft-Tissue Composition and the Distribution of Blue Cutaneous Discoloration in the Lower Eyelid after Hyaluronic Acid Injection.

The soft-tissue composition of the eyelid varies from lateral to medial, in that the orbicularis area (in square millimeters) is greatest medially and least laterally, whereas the reverse is true for the preauricularis and postorbicularis fat. The purpose of this study was to describe the relative contribution of tissue types to the volume of the lower eyelid-midface junction. This is an observational cohort study of 11 subjects (20 eyes) without a history of orbital or periorbital surgery or abnormality. Quasi-sagittal surface coil magnetic resonance imaging scans in planes parallel to the long axis of each orbit were obtained during central gaze fixation. Measurements of the tissue area (in square millimeters) of the skin, preorbicularis fat, orbicularis, and postorbicularis fat were obtained in the center, medial, and lateral eyelid regions. Differences in tissue area across the eyelid were assessed. The segmental cross-sectional area and percentage of total segment represented by the orbicularis muscle increased from the lateral (9.4 mm; 21.8 percent) to the central (14.1 mm; 35.0 percent) and to the medial (18.5 mm; 47.0 percent) eyelid (p < 0.01). The inverse pattern was noted for both preorbicularis and postorbicularis fat, each occupying less area (in square millimeters) from lateral to medial (p < 0.01). Skin thickness did not vary significantly across the eyelid. The soft-tissue composition of the eyelid varies from lateral to medial in that the orbicularis increases in area, whereas the reverse is true for the preorbicularis and postorbicularis fat. This anatomical progression may help to explain the stereotypical location of blue discoloration in some patients after hyaluronic acid filler injection.

Long-term results of surgical excision of conjunctival retention cyst using trypan blue with methylcellulose.

PURPOSE: Conjunctival retention cysts may recur if not completely removed. However, the cyst wall often ruptures during surgical excision, making complete removal difficult. In order to ensure complete cyst excision, we used a method of staining the inner cyst wall using trypan blue augmented by Methyl cellulose. OBSERVATION: Interventional study. Staining was performed by injecting trypan blue using an insulin needle. Then the needle was kept in place and methyl cellulose was injected to make the cyst content viscous to avoid its collapse after removing the needle. By using this technique, it was possible to excise the lesion as a whole. Three patients were included (unilateral). Two patients had cysts that were secondary to trachoma and were followed for up to 2 years without recurrence. A third patient had a conjunctival cyst following strabismus surgery was not successfully removed. CONCLUSION: This method is simple and effective for complete excision of conjunctival retention cysts exception for cysts post strabismus surgery.

Lateral rectus sag and recurrent esotropia in children.

PURPOSE: To describe the clinical and intraoperative findings of an anatomic abnormality in children that resembles sagging eye syndrome documented in older adults and that led to recurrent esotropia after surgery. METHODS: We reviewed records of 4 patients with substantial recurrent esotropia after bilateral medial rectus recession who required subsequent surgery combining lateral rectus resection with correction of the anatomic abnormality affecting the lateral rectus path. Binocular alignment was sequentially analyzed. RESULTS: Three young patients (2-3 years of age) presented with acquired esotropia but minimal cycloplegic refractive error. The fourth patient (14 years of age) initially had moderate hyperopia and partially accommodative esotropia, but subsequently developed marked bilateral overelevation in adduction. In all patients, esotropia recurred within 5Δ of preoperative deviation after bilateral medial rectus recession. Surgical exposure demonstrated that bilateral lateral rectus paths were inferiorly displaced more than one-half tendon width from their normal paths near the globe's equator, despite normal scleral insertions. Equatorial myopexy and lateral rectus resection resulted in stable esotropia correction. CONCLUSIONS: Lateral rectus sag in children creates a type of acquired esotropia and overelevation in adduction poorly responsive to standard surgery but correctable with lateral rectus resection and equatorial myopexy that normalizes the lateral rectus path through permanent scleral fixation.

Decompensated Esophoria as a Benign Cause of Acquired Esotropia.

PURPOSE: To determine informative clinical and magnetic resonance imaging (MRI) characteristics of patients with symptomatic adult acquired, comitant esotropia due to decompensated esophoria. DESIGN: Retrospective, interventional case series. METHODS: Setting: Institutional. STUDY POPULATION: Patients with decompensated esophoria who developed acute acquired comitant esotropia. OBSERVATION PROCEDURES: Ophthalmic examination, stereopsis, and strabismus measurements at distance and near using prism cover tests in diagnostic gaze positions were performed. Patients underwent high-resolution surface coil MRI of extraocular muscles with target fixation, and MRI of the brain. Strabismus surgery was performed under topical anesthesia with adjustable sutures wherever possible. Paired t testing was used to evaluate postoperative changes with 0.05 considered significant. MAIN OUTCOME MEASURE: Clinical and MRI characteristics, and surgical outcome of patients with decompensated esophoria. RESULTS: Eight cases were identified involving subjects of mean age 29 ± 9.4 (range: 20-48) years having gradually progressive intermittent horizontal, binocular diplopia for 10 months to 3 years. Mean preoperative esotropia was 31 ± 12 Δ at distance and 29 ± 12 Δ at near, although this was intermittent in 5 patients who exhibited enhanced fusional divergence. Neurologic evaluation and MRI of brain, orbits, and extraocular muscles were unremarkable in all cases. Orthotropia was successfully restored in all by standard or enhanced doses of bimedial rectus muscle recession surgery, improving mean stereoacuity from 535 to 68 arc seconds, although 5 patients exhibited 2-14 Δ asymptomatic residual esophoria. CONCLUSION: Decompensated esophoria is a benign clinical entity causing acute, acquired, comitant esotropia treatable with enhanced medial rectus recession.

The Globe's Eccentric Rotational Axis: Why Medial Rectus Surgery Is More Potent than Lateral Rectus Surgery.

PURPOSE: Tables typically recommend greater lateral rectus (LR) than medial rectus (MR) surgical doses for horizontal strabismus of any given magnitude, a difference unexplained by mechanical models that assume globe rotation about its center. We tested this assumption during horizontal ductions. DESIGN: Prospective observational study. PARTICIPANTS: Eighteen adult subjects with normal binocular vision. METHODS: Surface coil magnetic resonance imaging at 390 or 430 µm resolution was obtained using 2-mm-thick contiguous axial planes while subjects fixated targets in central, right, and left gaze. Angular displacements of lines connecting the corneal apex through the minor lens axis to the retina were measured to approximate clinical ductions. Globe centers were calculated from their area centroids. Apparent lens and globe-optic nerve (ON) junction rotations around the globe center were then compared with clinical ductions. MAIN OUTCOME MEASURES: Apparent angular rotations of lenses and globe-ON junctions during horizontal ductions. RESULTS: Globe-ON junctions appeared to rotate significantly less around globe centers than did lenses for abduction (20.6°±4.7° vs. 27.4°±7.4°, ± standard deviation (SD), P < 0.001) and adduction (25.3°±6.7° vs. 31.9°±8.3°, P < 0.001). Both rotations differed significantly from clinical adduction (27.9°±8.3°, P < 0.007), but only in abduction was globe-ON junction rotation significantly less than clinical abduction (28.6°±9.4°, P < 0.001). The true geometric globe rotational center was 2.2±0.5 mm medial and 0.8±1.0 mm posterior to the geometric globe center and was displaced farther medially and posteriorly during adduction. This eccentricity imbues each millimeter of MR recession with approximately 30% more trigonometric rotational effect than equivalent LR recession. CONCLUSIONS: The medial and posterior eccentricities of the normal ocular rotational axis profoundly influence horizontal rectus action. The proximity of the globe's rotational axis to the MR shortens its lever arm relative to the LR, explaining why mechanical effects of smaller MR recessions are equivalent to larger LR recessions.

Surgical success and lateral incomitance following three-muscle surgery for large-angle horizontal strabismus.

PURPOSE: To evaluate motor alignment, motility, and sensorial outcomes of simultaneous three-muscle surgery for large-angle horizontal strabismus, with special attention to lateral incomitance and long-term success. METHODS: The medical records of consecutive patients with large-angle deviations (≥30Δ) who underwent simultaneous surgery on three horizontal muscles to correct esotropia or exotropia were reviewed retrospectively. Successful motor alignment was defined as residual deviation of ≤10Δ and consecutive deviation in primary position of ≤4Δ, with no induced lateral incomitance >5Δ between lateral gazes. Sensory success was defined as an improvement in stereopsis of ≥2 octaves. Surgical procedures included a combination of recessions and resections/plications depending on surgeon preference. The majority of cases were two-muscle recessions combined with one-muscle resection or plication. RESULTS: A total of 19 patients with exotropia and 9 patients with esotropia were included. In the esotropic group, the mean age at surgery was 48 ± 15 years and the mean preoperative deviation improved from 45.6Δ ± 11.9Δ to 1.5Δ ± 1.6Δ (P < 0.001); there was no undercorrection, recurrence or overcorrection. In the exotropic group, the mean age at surgery was 44 ± 25 years, and the mean preoperative deviation improved from 44.1Δ ± 8.7Δ to 5.8Δ ± 9.6Δ (P < 0.001), recurrence occurred in 2 (22%). Overall motor success at distance was 85%, with 1 (3.8%) unsuccessful patient due to induced incomitance. Sensory success was 44% for esotropia and 31% for exotropia. No patient lost stereopsis. CONCLUSIONS: Patients undergoing three-muscle surgery for horizontal strabismus had good motor outcomes with low incidence of induced lateral incomitance. Motor and sensorial outcomes for esotropia were very stable.

Surgical interventions for vertical strabismus in superior oblique palsy.

BACKGROUND: Superior oblique palsy is a common cause of vertical strabismus in adults and children. Patients may be symptomatic from binocular vertical diplopia or compensatory head tilt required to maintain single vision. Most patients who are symptomatic elect to undergo strabismus surgery, but the optimal surgical treatment for vertical strabismus in people with superior oblique palsy is unknown. OBJECTIVES: To assess the relative effects of surgical treatments compared with another surgical intervention, non-surgical intervention, or observation for vertical strabismus in people with superior oblique palsy. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 12), MEDLINE Ovid (1946 to 13 December 2016), Embase Ovid (1947 to 13 December 2016), Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to 13 December 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch); searched 13 December 2016, ClinicalTrials.gov (www.clinicaltrials.gov); searched 13 December 2016, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en); searched 13 December 2016. We did not use any date or language restrictions in the electronic searches for trials. SELECTION CRITERIA: We included randomized trials that compared at least one type of surgical intervention to another surgical or non-surgical intervention or observation. DATA COLLECTION AND ANALYSIS: Two review authors independently completed eligibility screening, data abstraction, 'Risk of bias' assessment, and grading of the evidence. MAIN RESULTS: We identified two randomized trials comparing four different surgical treatments for this condition, two methods in each trial. The studies included a total of 45 children and adults. The surgical treatments were all procedures to weaken the ipsilateral inferior oblique muscle. One study compared inferior oblique myectomy to recession of 10 mm; the other study compared inferior oblique disinsertion to anterior transposition (2 mm anterior to the temporal border of the inferior rectus insertion).We judged both studies to be at unclear risk of bias due to incomplete reporting of methods and other methodological deficiencies.Neither study reported data on the primary outcome of this review, which was the proportion of participants with postoperative surgical success, defined as hypertropia less than 3 prism diopters (PD) in primary gaze. However, both studies reported the average reduction in hypertropia in primary gaze. One study found that at 12 months' postoperatively the average decrease in hypertropia was higher in participants who underwent inferior oblique myectomy than in those who underwent recession, however data were not available for statistical comparison. The other trial found that after at least six months of follow-up, the mean decrease in primary position hypertropia was lower in participants who underwent inferior oblique disinsertion than in those who underwent anterior transposition (mean difference (MD) -5.20 PD, 95% confidence interval (CI) -7.76 to -2.64; moderate-quality evidence).Both trials also reported the average postoperative reduction in vertical deviation in adduction. One study reported that the average reduction in hypertropia in adduction was greater in participants who underwent inferior oblique myectomy than in those who underwent recession, but data were not available for statistical comparison. The other study found a lower decrease in hypertropia in contralateral gaze in participants who underwent inferior oblique disinsertion than in those who underwent anterior transposition (MD -7.10 PD, 95% CI -13.85 to -0.35; moderate-quality evidence).Secondary outcomes with sufficient data for analysis included proportion of participants with preoperative head tilt that resolved postoperatively and proportion of participants who underwent a second surgery. These outcomes were assessed in the trial comparing inferior oblique anterior transposition to disinsertion; both outcomes favored anterior transposition (risk ratio 7.00, 95% CI 0.40 to 121.39 for both outcomes; very low-quality evidence). None of the participants who underwent inferior oblique anterior transposition or disinsertion developed postoperative hypotropia or reversal of the vertical deviation. All participants who underwent inferior oblique anterior transposition developed elevation deficiency, which the authors deemed to be clinically insignificant in all cases, whereas no participants who underwent inferior oblique disinsertion experienced this complication. Additionally, the trial comparing inferior oblique myectomy to recession reported that no participant in either group required another strabismus surgery during the postoperative period. AUTHORS' CONCLUSIONS: The two trials included in this review evaluated four inferior oblique weakening procedures for surgical treatment of superior oblique palsy. We found no trials comparing other types of surgical procedures for this disorder. Both studies had enrolled a small number of participants and provided low-quality evidence due to limitations in completeness and applicability. We therefore found no high-quality evidence to support recommendations for optimal surgical treatment of superior oblique palsy. Rigorously designed, conducted, and reported randomized trials are needed to identify the optimal surgical treatment for vertical strabismus in this disorder.

Decreased Binocular Summation in Strabismic Amblyopes and Effect of Strabismus Surgery.

PURPOSE: Binocular summation (BiS) occurs when binocular visual function surpasses that of the better eye alone. We sought to evaluate whether strabismic amblyopia reduces BiS more than strabismus alone, and determine whether BiS improves in strabismic amblyopes after strabismus surgery. METHODS: We prospectively recruited 15 patients with strabismic amblyopia who then underwent strabismus surgery. Thirty age-matched normal subjects and 30 non-amblyopic strabismic patients served as controls. Subjects underwent binocular and monocular visual acuity testing on high-contrast Early Treatment Diabetic Retinopathy Study (ETDRS) as well as 2.5% and 1.25% Sloan low contrast acuity (LCA) charts. BiS was calculated as the difference between better eye and binocular scores. RESULTS: Strabismic amblyopes and strabismic controls did not significantly differ in preoperative BiS, but both had subnormal BiS preoperatively on LCA charts. Among 11 strabismic amblyopes with preoperative and postoperative BiS measurements, average postoperative BiS was not significantly different from preoperative. Improved LCA BiS postoperatively occurred in some patients and was associated with measurable preoperative stereoacuity (P=0.02), older age at strabismus onset (P=0.02), and larger preoperative angle of strabismus (P=0.0043). CONCLUSIONS: In this preliminary study, strabismic amblyopes experienced subnormal BiS, but amblyopia generally did not further impair BiS beyond that due to strabismus alone. Some strabismic amblyopes experienced improved low-contrast BiS after strabismus surgery. This suggests that further investigation in larger groups of patients should be undertaken to analyze a previously unrecognized functional benefit of strabismus surgery in strabismic amblyopes.

Binocular Summation and Control of Intermittent Exotropia.

BACKGROUND: Binocular summation (BiS), or improvement in binocular vision exceeding the better eye alone, is affected by strabismus. Being easily measured, BiS may be a useful indicator for subjective outcomes like stereopsis in strabismus. This study aims to investigate the relationship between BiS and measures of control of intermittent exotropia (IXT). METHODS: Patients with IXT were recruited before undergoing strabismus surgery and underwent tests of binocular and monocular high- and low-contrast visual acuity, stereopsis at distance and near, and Newcastle Control Score (NCS), a score developed by incorporating home control and clinic control criteria into a control rating scale. BiS was calculated using high-contrast Early Treatment of Diabetic Retinopathy Study (ETDRS) and Sloan low-contrast acuity charts (LCA) at 2.5% and 1.25% contrast as the difference between the binocular score and that of the better eye. The relationship between BiS and measures of IXT control (NCS and distance near stereoacuity disparity) was evaluated using a correlation analysis by Spearman correlation coefficients and the Kruskal-Wallis test. RESULTS: Thirty-four patients were included (mean [± standard deviation (SD)] age 19±16 years) having a mean (±SD) of 26±16Δ IXT at distance and 20±16Δ at near. Mean (±SD) BiS for ETDRS and Sloan LCA at 2.5% and 1.25% was 0.8±3.6, 1.9±6.0, and -2.3±7.2, respectively. The Spearman correlation coefficient of BiS and NCS was -0.53 (95% CI -0.85 to -0.25) for 2.5% LCA and -0.43 (95% CI -0.77 to -0.13) for 1.25% LCA. BiS at 2.5% LCA (P=0.006) and at 1.25% LCA (P=0.029) significantly differed between the groups based on NCS score groupings (1-3, 4-6, and 7-9), with patients who had better control scores having higher levels of BiS. BiS did not differ significantly between patients grouped according to the difference between stereoacuity measured at near versus distance. CONCLUSION: Significantly lower low-contrast BiS in patients with higher NCS may suggest that decreased BiS is associated with less control in IXT. This finding suggests that BiS may reflect control in IXT across a population of patients with IXT.

Isolated schwannoma involving extraocular muscles.

BACKGROUND: Progressive strabismus initially considered idiopathic may be caused by isolated schwannomas of motor nerves to extraocular muscles, detectable only on careful imaging. This study reviewed clinical experience of a referral practice in identifying schwannomas on magnetic resonance imaging (MRI). METHODS: We reviewed 647 cases imaged for strabismus to identify presumed cranial nerve schwannomas, identified by gadodiamide-enhanced, high-resolution surface coil orbital MRI and thin-section cranial MRI. Clinical features and management were correlated with MRI. RESULTS: Schwannomas were identified as fusiform intraneural enlargements in 8 cases: 1 affecting the trochlear nerve; 2, the abducens nerve; and 5 the oculomotor nerve. Involved muscles were atrophic. Both abducens schwannomas, 1 superior oblique, and 1 oculomotor schwannoma were subarachnoid; 3 were intraorbital, and bilateral oculomotor lesions of 1 case extended from cavernous sinus to orbit. Associated strabismus progressed for 3-17 years. Abducens schwannoma caused esotropia; trochlear schwannoma caused hypertropia and cyclotropia. Intracranial oculomotor schwannoma caused mydriasis and exotropia. Intraorbital schwannoma caused exotropia with or without hypertropia. Since lesion diameters were 3-9 mm, 6 had been previously missed on routine MRI. CONCLUSIONS: Progressive, acquired strabismus may be caused by isolated cranial nerve schwannomas, representing about 1% of strabismus cases in this study, involving the oculomotor more than abducens nerve. Because most schwannomas are small and deep in the orbit, findings could be readily missed by routine imaging, leading to a possible diagnosis of idiopathic strabismus. Schwannomas should be suspected when extraocular muscles are atrophic, but the causative lesions themselves are identifiable only using targeted, high resolution MRI.

Relationship Between Binocular Summation and Stereoacuity After Strabismus Surgery.

PURPOSE: To describe the relationship between binocular summation and stereoacuity after strabismus surgery. DESIGN: Prospective case series. METHODS: setting: Stein Eye Institute, University of California Los Angeles. PATIENT POPULATION: Pediatric strabismic patients who underwent strabismus surgery between 2010 and 2015. OBSERVATION PROCEDURES: Early Treatment Diabetic Retinopathy Study visual acuity, Sloan low-contrast acuity (LCA, 2.5% and 1.25%), and Randot stereoacuity 2 months following surgical correction of strabismus. MAIN OUTCOME MEASURES: The relationship between binocular summation (BiS), calculated as the difference between the binocular visual acuity score and that of the better eye, and stereoacuity. RESULTS: A total of 130 postoperative strabismic patients were studied. The relationship between binocular summation and stereoacuity was studied by Spearman correlation. There were significant correlations between BiS for 2.5% LCA with near and distance stereoacuity (P = .006 and P = .009). BiS for 1.25% LCA was also significantly correlated with near stereoacuity (P = .04). Near stereoacuity and BiS for 2.5% and 1.25% LCA were significantly dependent (Pearson χ(2), P = .006 and P = .026). Patients with stereoacuity demonstrated significantly more BiS in 2.5% LCA of 2.7 (P = .022) and 3.1 (P = .014) letters than did those without near or distance stereoacuity, respectively. CONCLUSIONS: These findings demonstrate that stereopsis and binocular summation are significantly correlated in patients who have undergone surgical correction of strabismus.

Heavy eye syndrome versus sagging eye syndrome in high myopia.

BACKGROUND: Heavy eye syndrome (HES) presents with esotropia and limited abduction due to superotemporal globe shift relative to the extraocular muscles. Sagging eye syndrome (SES) was originally described in nonmyopic patients exhibiting distance esotropia and cyclovertical strabismus with limited supraduction due to lateral rectus muscle inferodisplacement caused by degeneration of the lateral rectus-superior rectus (LR-SR) band. We hypothesized that SES might also cause strabismus in high myopia. METHODS: Eleven strabismic subjects with high myopia underwent ophthalmological examination and orbital magnetic resonance imaging (MRI) to assess quantitative orbital anatomy. RESULTS: Of 11 subjects, 5 had HES; 6, SES. Mean axial length in subjects with HES was 32 ± 5 mm; in subjects with SES, 32 ± 6 mm. Average distance esotropia in subjects with HES was 61(Δ) ± 39(Δ); hypotropia was 26(Δ) ± 21(Δ). Average distance esotropia in subjects with SES was 23(Δ) ± 57(Δ); hypertropia was 2(Δ) ± 2(Δ). All 5 subjects with HES had superotemporal globe prolapse; the LR-SR band was thinned in 6 orbits and ruptured in 2. The mean angle between the lateral rectus and superior rectus muscles in HES was 121° ± 7°. In SES the LR-SR band was thinned in 7 orbits and ruptured in 5, with superotemporal soft tissue prolapse. The mean angle between the lateral rectus and superior rectus muscles was 104° ± 11°, significantly less than in HES (P < 0.001). CONCLUSIONS: SES occurs in highly myopic patients who also exhibit less relative globe dislocation than in HES. Unlike HES, SES exhibits superotemporal soft tissue prolapse that may limit superotemporal globe shift. The distinction is important because surgery for HES uniquely requires creation of a surgical connection between the superior rectus and lateral rectus muscles, whereas SES may be treated with conventional surgery. SES can cause strabismus in high axial myopia. Orbital MRI is useful in differentiating SES from HES.

Magnetic resonance imaging of bilateral split lateral rectus transposition to the medial globe.

PURPOSE: Medial transposition of the split or intact lateral rectus (LR) muscle in oculomotor palsy improves extreme exotropia. We studied rectus pulley positions using high-resolution surface coil MRI before and after LR split with medial transposition surgery in a patient with bilateral oculomotor and trochlear nerve palsies. METHODS: This is a report of a 14-year-old girl with 90Δ exotropia due to bilateral oculomotor and trochlear nerve palsies following traumatic midbrain infarction at age 6 years. Surgery comprised longitudinal division of each LR into a superior and inferior, threading of both halves between the inferior rectus (IR) and inferior oblique inferiorly, and inferior to the superior oblique and the superior rectus superiorly, with suturing of each 10 mm posterior to the medial rectus (MR) insertion. RESULTS: Pre-operative MRI of the orbit and extraocular muscles (EOMs) with thin, 2-mm slices revealed bilateral atrophy of all EOMs supplied by the oculomotor and trochlear nerves. Post-operative MRI at 2 months demonstrated no significant changes in rectus EOM pulley positions compared with pre-operative values. CONCLUSIONS: The LR pulley does not change position even after split LR transposition to the MR insertion, confirming the profound constraint of the connective tissue pulley system on the LR path.