Abstract Since the first description of sound-evoked short-latency myogenic reflexes recorded from neck muscles, vestibular evoked myogenic potentials (VEMPs) have become an important part of the ...neuro-otological test battery. VEMPs provide a means of assessing otolith function: stimulation of the vestibular system with air-conducted sound activates predominantly saccular afferents, while bone-conducted vibration activates a combination of saccular and utricular afferents. The conventional method for recording the VEMP involves measuring electromyographic (EMG) activity from surface electrodes placed over the tonically-activated sternocleidomastoid (SCM) muscles. The “cervical VEMP” (cVEMP) is thus a manifestation of the vestibulo-collic reflex. However, recent research has shown that VEMPs can also be recorded from the extraocular muscles using surface electrodes placed near the eyes. These “ocular VEMPs” (oVEMPs) are a manifestation of the vestibulo-ocular reflex. Here we describe the historical development and neurophysiological properties of the cVEMP and oVEMP and provide recommendations for recording both reflexes. While the cVEMP has documented diagnostic utility in many disorders affecting vestibular function, relatively little is known as yet about the clinical value of the oVEMP. We therefore outline the known cVEMP and oVEMP characteristics in common central and peripheral disorders encountered in neuro-otology clinics.
Purpose
This study aimed to investigate the factors affecting extraocular muscle enlargement in thyroid eye disease (TED).
Study design
Retrospective study.
Methods
The thyroid-stimulating hormone ...(TSH) receptor antibody (TRAb), thyroid-stimulating antibody (TSAb), antithyroid peroxidase antibody (ATPO), and antithyroglobulin antibody (ATG) levels in patients diagnosed with TED who underwent orbital magnetic resonance imaging were assessed. The control group comprised the contralateral eye of patients who underwent orbital magnetic resonance imaging (MRI) for unilateral eyelid tumors or orbital disease. The thickness of the bilateral rectus muscles and superior oblique muscles was measured on orbital MRI. Muscle enlargement was classified as unilateral/bilateral and symmetric/asymmetric. The effects of age, sex, smoking history, TSH, thyroid hormone, and thyroid autoantibodies on the muscle thickness and number of enlarged muscles were assessed by use of simple and multiple regression analyses.
Results
The TED and control groups comprised 41 and 44 cases, respectively. The positivity rate of TSAb in patients with TED was 92.7% higher than that of the other autoantibodies. Muscle enlargement was observed in 29 of the 41 cases (70.7%). Older age and higher TSAb levels were identified as significant factors affecting the total muscle thickness and number of enlarged muscles. Bilateral muscle enlargement and asymmetrical muscle enlargement were observed in 17 (58.6%) and 23 (79.3%) of the 29 cases, respectively. The TSAb levels and age had no significant effect on the type of muscle enlargement.
Conclusions
TSAb showed significant associations with extraocular muscle enlargement. Measurement of TSAb, rather than of TRAb, may be more useful for diagnosing extraocular muscle enlargement in patients with TED.
To determine the incidence and type of strabismus in patients with uveal melanoma treated with plaque brachytherapy.
Multicenter, retrospective incidence estimation study.
A total of 438 eyes of 438 ...patients with uveal melanoma treated with plaque brachytherapy between October 2011 and May 2021. Intervention was Iodine 125, and Palladium 103 plaque brachytherapy. The variables reviewed included incidence of nonresolving strabismus post–plaque brachytherapy, type of strabismus developed, extraocular muscles operated, and modality of treatment received.
A total of 438 patients underwent plaque brachytherapy treatment for uveal melanoma. Eleven patients developed strabismus post–plaque brachytherapy (2.5%, n = 11/438). Of these patients, 5 (1.1%, n = 5/438) developed strabismus immediately postoperation. Specifically, 2 patients (0.5%, n = 2/438) developed strabismus immediately postoperation due to slipped muscles, 2 patients (0.5%, n = 2/438) due to decompensated phorias, and 1 patient (0.5%, n = 1/438) due to a fibrotic muscle. Six patients (1.4%, n = 6/438) developed late-onset sensory strabismus. A total of 355 patients (81.1%, n = 355/438) had their extraocular muscles disinserted during surgery, with the lateral rectus being the most common, accounting for 45.4% (n = 161/355), followed by the superior rectus at 26.8% (n = 95/355). Strabismus surgery was the most common treatment modality, comprising 72.7% (n = 8/11) of patients.
The incidence of strabismus after plaque brachytherapy treatment for uveal melanoma was low and primarily classified as late-onset sensory strabismus. Previous studies may underestimate the long-term incidence of strabismus after plaque brachytherapy by focusing primarily on strabismus present immediately postoperatively.
To investigate the results of patients undergoing surgical treatment for strabismic diplopia in thyroid eye disease (TED) following teprotumumab.
Multicenter, retrospective, case series.
We 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.
Sixteen (57%) patients were diplopia-free after 1 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.
Most patients requiring surgery for strabismic diplopia following teprotumumab achieve good outcomes with success rates comparable to series published before the availability of teprotumumab.
A wearable optical apparatus that compensates for eye misalignment (strabismus) to correct for double vision (diplopia) is proposed. In contrast to prism lenses, commonly used to compensate for ...horizontal and/or vertical misalignment, the proposed approach is able to compensate for any combination of horizontal, vertical, and torsional misalignment.
If the action of the extraocular muscles is compromised (e.g., by nerve damage), a patient may lose their ability to maintain visual alignment, negatively affecting their binocular fusion and stereo depth perception capability. Torsional misalignment cannot be mitigated by standard Fresnel prism lenses. Surgical procedures intended to correct torsional misalignment may be unpredictable. A wearable device able to rectify visual alignment and restore stereo depth perception without surgical intervention could potentially be of great value to people with strabismus.
We propose a novel lightweight wearable optical device for visual alignment correction. The device comprises two mirrors and a Fresnel prism, arranged in such a way that together they rotationally shift the view seen by the affected eye horizontally, vertically, and torsionally. The extent of the alignment correction on each axis can be arbitrarily adjusted according to the patient's particular misalignment characteristics.
The proposed approach was tested by computer simulation, and a prototype device was manufactured. The prototype device was tested by a strabismus patient exhibiting horizontal and torsional misalignment. In these tests, the device was found to function as intended, allowing the patient to enjoy binocular fusion and stereo depth perception while wearing the device for daily activities over a period of several months.
The proposed device is effective in correcting arbitrary horizontal, vertical, and torsional misalignment of the eyes. The results of the initial testing performed are highly encouraging. Future study is warranted to formally assess the effectiveness of the device on multiple test patients.
Masquerading Superior Oblique Palsy Demer, Joseph L.; Clark, Robert A.
American journal of ophthalmology,
10/2022, Letnik:
242
Journal Article
Recenzirano
Odprti dostop
: We evaluated patients with hypertropia compatible with diagnosis of superior oblique (SO) palsy to ascertain if 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.
: 57 patients (average age 39±21 years, standard deviation, SD) had unilateral SOP manifested by SO atrophy (22 congenital and 35 acquired). There was normal SO size in 26 (age 39±16 years) considered masquerades (8 congenital and 18 acquired). Maximum palsied SO cross section averaged 9.5±3.8mm2, less than 18.4±3.9mm2 contralaterally (P<10−24). In masquerades, maximum hypertropic SO cross section was 20.7±3.1mm2, not different from the hypotropic SO or the contralesional muscle in SO palsy. Head tilt testing in masquerades was indistinguishable from SOP. In SOP, 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 HT 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±8.4 Δ in acquired SOP (P=0.025), but 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.
Unraveling the genetics of the paralytic strabismus syndromes known as congenital cranial dysinnervation disorders (CCDDs) is both informing physicians and their patients and broadening our ...understanding of development of the ocular motor system. Genetic mutations underlying ocular CCDDs alter either motor neuron specification or motor nerve development, and highlight the importance of modulations of cell signaling, cytoskeletal transport, and microtubule dynamics for axon growth and guidance. Here we review recent advances in our understanding of two CCDDs, congenital fibrosis of the extraocular muscles (CFEOM) and Duane retraction syndrome (DRS), and discuss what they have taught us about mechanisms of axon guidance and selective vulnerability. CFEOM presents with congenital ptosis and restricted eye movements, and can be caused by heterozygous missense mutations in the kinesin motor protein KIF21A or in the β-tubulin isotypes TUBB3 or TUBB2B. CFEOM-causing mutations in these genes alter protein function and result in axon growth and guidance defects. DRS presents with inability to abduct one or both eyes. It can be caused by decreased function of several transcription factors critical for abducens motor neuron identity, including MAFB, or by heterozygous missense mutations in CHN1, which encodes α2-chimaerin, a Rac-GAP GTPase that affects cytoskeletal dynamics. Examination of the orbital innervation in mice lacking Mafb has established that the stereotypical misinnervation of the lateral rectus by fibers of the oculomotor nerve in DRS is secondary to absence of the abducens nerve. Studies of a CHN1 mouse model have begun to elucidate mechanisms of selective vulnerability in the nervous system.
The purpose of this study is to present the possibilities and benefits of ultrasonography (US) of the orbit in the diagnosis and treatment of thyroidassociated orbitopathy (TAO). Methods: US ...examination of the orbit is an essential addition to clinical and laboratory examination in TAO patients. Nevertheless, it is often neglected in clinical practice or indicated with delay. Based on previously published studies and our experience with the diagnosis and treatment of TAO patients, we aim to highlight the clear benefit of US examination of the orbit and oculomotor muscles, not only for correct TAO diagnosis but also in the monitoring of the disease over time. However, knowledge of the drawbacks and limitations of this method is also essential, as we shall point out. It is always necessary to remember that US examination must be evaluated in connection with the clinical findings. A detailed recommendation for US examination of the extraocular muscles and the orbit based on our experiences with diagnosing and treating TAO patients in daily practice is also included. Conclusion: According to our experience, US examination of the orbit is an excellent and irreplaceable tool for timely TAO diagnosis and further disease monitoring. However, considerable examiner experience and detailed knowledge of the clinical and ultrasound manifestations of TAO are essential.
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