Predominant Contribution of Superior Rectus–Levator Complex Enlargement to Optic Neuropathy and Inferior Visual Field Defects in Thyroid Eye Disease

Diagnostic methods for dysthyroid optic neuropathy: A systematic review and analysis

Diagnosis of dysthyroid optic neuropathy (DON) typically relies on a set of diagnostic clinical features, including decreased visual acuity, impaired color vision, presence of relative afferent pupillary defect, optic disc swelling and ancillary tests including visual field (VF), pattern visual evoked potential (pVEP), and apical crowding or optic nerve stretching on neuroimaging. We summarize various diagnostic methods to establish or rule out DON. A total of 95 studies (involving 4619 DON eyes) met the inclusion criteria. All of the studies considered clinical features as evidence of DON, while most of the studies confirmed DON diagnosis by combining clinical features with ancillary tests. Forty studies (42.1%) used at least 2 out of the 3 tests (VF, pVEP and neuroimaging) and 13 studies (13.7%) used all 3 tests to diagnose DON. In 64 % of the published studies regarding DON, the diagnostic methods of DON were not specified. It is important to note the limitations of relying solely on clinical features for diagnosing DON. On the other hand, since some eyes with optic neuropathy can be normal in one ancillary test, but abnormal in another, using more than one ancillary test to aid diagnosis is crucial and should be interpreted in correlation with clinical features. We found that the diagnostic methods of DON in most studies involved using a combination of specific clinical features and at least 2 ancillary tests.

Surgical management of dysthyroid optic neuropathy: A systematic review

OBJECTIVE

There is currently no recommendation on the optimal surgical management for dysthyroid optic neuropathy (DON). The aim of this study is to systematically review the surgical management of DON and its outcome on visual acuity (VA).

DATA SOURCES

MEDLINE, Cochrane Library, and clinicaltrials.gov REVIEW METHODS: A systematic review of studies about the surgical management of DON was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Articles were included if preoperative and postoperative VA in logMAR (Logarithm of the Minimum Angle of Resolution) were available.

RESULTS

Fifteen articles were included in the study accounting for 669 orbits. The mean VA improvement was of 0.44 logMAR overall, 0.41 logMAR for 1-wall, 0.41 logMAR for 2-wall, and 0.55 logMAR for 3-wall decompressions. The mean reduction in exophthalmos was 4.9 mm overall, 4.3 mm for 1-wall, 4.54 mm for 2-wall, and 6.02 for 3-wall decompressions. The mean new onset diplopia (NOD) rate was 19.84% overall, 19,12% for 1-wall, 20.75% for 2-wall, and 19.83% for 3-wall decompressions.

CONCLUSION

The results are limited due to the high number of biases in the included studies. It seems that 3-wall decompression offers the best VA improvement and proptosis reduction although also the highest NOD and complications rate. Two-wall balanced decompression or 1-wall inferomedial decompression seems to be effective with less morbidity.

Extraocular muscle enlargement in dysthyroid optic neuropathy

OBJECTIVE

To investigate extraocular muscle volumes in thyroid eye disease (TED) patients with and without dysthyroid optic neuropathy (DON).

DESIGN

Retrospective cohort study.

PARTICIPANTS

TED patients who had computed tomography of the orbits.

METHODS

The extraocular muscles were manually segmented in consecutive axial and coronal slices, and the volume was calculated by summing the areas in each slice and multiplying by the slice thickness. Data were collected on patient demographics, disease presentation, thyroid function tests, and antibody levels.

RESULTS

Imaging from 200 orbits was evaluated. The medial rectus, lateral rectus, superior muscle group, inferior rectus, and superior oblique volumes were significantly greater in orbits with DON compared with TED orbits without DON (p < 0.01 for all). There was no significant difference in the inferior oblique muscle volume (p = 0.19). Increase in volume of the superior oblique muscle showed the highest odds for DON. Each 100 m3 increase in superior oblique, lateral rectus, inferior rectus, medial rectus, and superior muscle group volume was associated with 1.58, 1.25, 1.20, 1.16, and 1.14 times increased odds of DON.

CONCLUSION

All extraocular muscle volumes except for the inferior oblique were significantly greater in DON patients. Superior oblique enlargement was associated with the highest odds of DON, suggesting superior oblique enlargement to be a novel marker of DON.

Dysthyroid Optic Neuropathy

PURPOSE

Dysthyroid optic neuropathy (DON) is a sight-threatening complication of thyroid eye disease (TED). This review provides an overview of the epidemiology, pathogenesis, diagnosis, and current therapeutic options for DON.

METHODS

A literature review.

RESULTS

DON occurs in about 5% to 8% of TED patients. Compression of the optic nerve at the apex is the most widely accepted pathogenic mechanism. Excessive stretching of the nerve might play a role in a minority of cases. Increasing age, male gender, smoking, and diabetes mellitus have been identified as risk factors. Diagnosis of DON is based on a combination of ≥2 clinical findings, including decreased visual acuity, decreased color vision, relative afferent pupillary defect, visual field defects, or optic disc edema. Orbital imaging supports the diagnosis by confirming apical crowding or optic nerve stretching. DON should be promptly treated with high-dose intravenous glucocorticoids. Decompression surgery should be performed, but the response is incomplete. Radiotherapy might play a role in the prevention of DON development and may delay or avoid the need for surgery. The advent of new biologic-targeted agents provides an exciting new array of therapeutic options, though more research is needed to clarify the role of these medications in the management of DON.

CONCLUSIONS

Even with appropriate management, DON can result in irreversible loss of visual function. Prompt diagnosis and management are pivotal and require a multidisciplinary approach. Methylprednisolone infusions still represent first-line therapy, and surgical decompression is performed in cases of treatment failure. Biologics may play a role in the future.

[Thyroid Eye Disease-Compressive Optic Neuropathy]

BACKGROUND

The aim of this study was to evaluate the functional outcomes in terms of best-corrected visual acuity (BCVA) and visual field (VF) defects in optic nerve compression (thyroid eye disease-compressive optic neuropathy, TED-CON) patients after treatment.

PATIENTS AND METHODS

In this observational, retrospective study, the medical charts of 51 patients (96 eyes) with a diagnosis of definitive TED-CON between 2010-2020 were included.

RESULTS

After the diagnosis of TED-CON, 16 patients (27 eyes) received steroid-pulse (medical) treatment alone, 67 eyes received an additional surgical orbital decompression, whereas 1 patient (2 eyes) refused both treatment methods. In 74 eyes (77.1%) we detected an improvement of the BCVA ≥ 2 lines after the treatment over a mean time interval of 31.7 weeks (with no significant difference between treatment methods). In 22 eyes (27.2%) out of the 81 that underwent a posttreatment VF examination, we observed a complete resolution of the defects over a mean time interval of 39.9 weeks. When we limited analysis to patients with a minimum follow-up of 6 months at last visit, we found 33 eyes (61.1%) out of 54 eyes still had a VF defect.

CONCLUSION

In our data, more than half of the TED-CON cases (61.5%) had a good prognosis with a final BCVA ≥ 0.8  at the last visit; however, only 22 eyes (27.2%) showed a complete resolution of VF defects, while 33 eyes (61.1%) had residual defects measured after a minimum follow-up of 6 months. These results suggest that while the BCVA recovers relatively well, the VF of patients is likely to remain marked by optic nerve compression.

A single-institution review of lacrimal gland biopsies between 1962 and 2017

PURPOSE

To examine the clinical and histopathologic characteristics of lacrimal gland biopsies at a tertiary academic center.

METHODS

A retrospective chart review of patients undergoing lacrimal gland biopsy or excision between 1962 and 2017 was performed via the ocular pathology specimen log. All cases were reviewed for demographics, clinical presentation, and histopathologic diagnoses.

RESULTS

Four hundred and two eyes in 356 patients were included in the analysis. Median age was 49 (range 5-91) with a female predominance (255, 72%, p < .001). Most had unilateral involvement (308, 86.5%) and visual acuity of 20/50 or better (332 eyes, 83%). Limitation in extraocular motility was present in 71 eyes (18%), relative afferent pupillary defect in 10 eyes (2.5%), and intraocular pressure 20 mmHg or above in 80 eyes (20%). The pre-operative radiology report commented on the enlargement of the lacrimal gland in 236 eyes (58.7%), and lack thereof in 73 eyes (18.2%). The most common histopathologic diagnoses were nonspecific inflammation or orbital pseudotumor (170, 42%), lymphoma (65, 16%), pleomorphic adenoma (22, 5.5%), adenoid cystic carcinoma (19, 4.7%), granulomatous inflammation (19, 4.7%), and normal lacrimal gland (16, 4%). Three hundred and seven cases were benign (76%) and 95 malignant (24%). The biopsy specimen was diagnostic in 343 (85%), and non-diagnostic in 59 (15%).

CONCLUSIONS

This is a comprehensive review of one of the largest ocular pathology databases of lacrimal gland lesions. This study confirms the wide range of inflammatory and neoplastic conditions affecting the lacrimal gland and highlights the nuances of histopathologic diagnoses and diagnostic yield of biopsies in clinical practice.

Extraocular muscle enlargement

Extraocular muscle enlargement can occur secondary to a range of orbital and systemic diseases. Although the most common cause of extraocular muscle enlargement is thyroid eye disease, a range of other inflammatory, infective, neoplastic, and vascular conditions can alter the size and shape of the extraocular muscles. Imaging with computed tomography and magnetic resonance imaging plays an essential role in the workup of these conditions. This article provides an image-rich review of the wide range of pathology that can cause enlargement of the extraocular muscles.

Single-stage Orbital Decompression, Strabismus and Eyelid Surgery in Moderate to Severe Thyroid Associated Orbitopathy

PURPOSE

To evaluate the outcome of orbital decompression, strabismus and/or eyelid surgery in patients with moderate to severe thyroid-associated orbitopathy, when combined approach is preferred.

METHODS

Retrospective, comparative, non-randomized review of 45 patients operated on from 2015 to 2018. Simultaneous decompression, eyelid and/or strabismus surgery was performed in 34 eyes of 20 subjects (group 1). Patients with multi-step procedures were used as control groups: group 2 included patients with staged decompression and eyelid retraction surgery (15 cases, 19 eyes); group 3 included patients with staged decompression and vertical strabismus surgery (10 cases, 13 eyes). Mean follow-up was 2.9 ± 1.8 years. Mann Whitney two-tailed test was used for paired data, and Fisher's exact test for categorical data; p <.05 were considered statistically significant.

RESULTS

Changes in margin reflex distance were not significantly different among patients of subgroup 1A (11 patients, one-step decompression/eyelid surgery) and group 2 (p >.05). Improvement in postoperative diplopia were not significantly different among patients of subgroup 1B (9 cases, one-step decompression/strabismus/eyelid surgery) and group 3 (p >.05). One patient of group 1 had recurrent dysthyroid optic neuropathy that recovered with steroid treatment. No other complications occurred in the one-step surgery group.

CONCLUSIONS

Simultaneous orbital decompression, strabismus and/or eyelid surgery resolved dysthyroid optic neuropathy, decreased proptosis, improved diplopia and eyelid position with a range comparable to that of a multi-step technique. If confirmed in prospective controlled studies, a one-stage approach might be advised to reduce the costs and time needed for rehabilitation in selected patients.

Compressive optic neuropathy (CON) in Graves' disease caused by hypertrophy of levator and superior rectus muscles: A case report

RATIONALE

Enlargemento of the medial rectus is the most predominant factor of compressive optic neuropathy (CON) in Graves' disease. This case report indicates that CON could develop only from the hypertrophic superior levator and superior rectus (SL/SR) muscle in a patient with poorly controlled Graves' disease, and described the possible risk of FT3-thyrotoxicosis with a prominent goiter to develop the current rare case with a review of the literature.

PATIENT CONCERNS

A 66-year-old woman undergoing endocrine management of hyperthyroidism with prominent goiter visited the Department of Ophthalmology due to right-eye upper-eyelid retraction.

DIAGNOSES

At initial presentation, the right and left margin reflex distance-1 (MRD-1) was 3.2 mm and 2.1 mm, respectively, and no proptosis or visual dysfunction was observed. Despite insufficient hormonal regulation, she refused to undergo goiter removal. The upper eyelid retraction gradually worsened to 7.7 mm of MRD-1, followed by the onset of 20 prism diopters (PD) of the right hypertropia, resulting in right-eye CON after 6 months. Her free thyroxin level was 3.88 ng/dl and free triiodothyronine was 24.90 pg/ml. Computed tomography and magnetic resonance imaging showed only SL/SR enlargement in the right orbit.

INTERVENTIONS

Intravenous steroid and radiation therapy resulted in visual improvement; however, a prominent upper eyelid retraction and 35PD of hypertropia remained in her right eye. Orbital decompression, upper retraction repair, and superior rectus recession were performed to prevent the recurrence of CON and correct any disfigurement.

OUTCOMES

The combination of conventional intravenous steroid pulse therapy, radiotherapy, and orbital decompression was effective, and no recurrence was observed for more than 1.5-years postoperatively.

LESSONS

Enlargement of the SL/SR muscle complex may independently induce the CON. We believe that strict attention should be paid to patients with triiodothyronine thyrotoxicosis with progressive eyelid retraction and hypertropia.

Dysthyroid optic neuropathy: evaluation and management

BACKGROUND

Dysthyroid optic neuropathy (DON) is a serious complication of Graves orbitopathy (GO) from optic nerve dysfunction that may result in permanent loss of vision.

PURPOSE

This paper reviews the current knowledge of DON, including its pathogenesis and epidemiology, clinical and radiologic features, and management choices and outcomes.

METHODS

Literature review and author retrospective case series.

RESULTS

Over 90% of DON cases are related to nerve compression by enlarged extraocular muscles (EOM) while the remainder are caused by stretching of the optic nerve without compression. DON's incidence is 5-8% of GO cases. Risk factors include advancing age, male gender, smoking and diabetes mellitus, and these cases should be referred promptly to an ophthalmologist or GO clinic to rule out DON and for ongoing care. Clinical features of DON may include reduction in central and colour vision (unexplained by other ocular disorders), afferent pupil defect and/or optic disc edema. Since most cases are associated with enlarged EOM, restricted motility and soft tissue venous congestion are common. Visual fields and optical coherence tomography (OCT) help confirm the diagnosis while CT or MRI Scans show apical optic nerve compression or proptosis with optic nerve stretch. Standard therapy includes iv/oral corticosteroids (CS) with partial response in most cases, but often relapse with tapering. Radiotherapy may delay or avoid surgery and may prevent the onset of DON when combined with CS in high-risk individuals. The benefits of newer biologic targeted therapy are not clear. Orbital decompression surgery often has positive outcomes, even in cases of severe vision loss or delayed surgery. The most common surgical complication is worsening strabismus, which may worsen visual function and quality of life. In rare cases, permanent vision loss from DON may occur despite full therapy.

CONCLUSIONS

Although DON may cause vision loss, most cases are reversible if recognized and managed in a timely manner.

Evolution of thyroid eye disease decompression-dysthyroid optic neuropathy

Orbital decompression surgery and medical therapy for thyroid eye disease (TED) have evolved over the past 150 years and afforded the opportunity to restore pre-disease appearance and visual function. This manuscript explores the past 150 years of surgical innovation for the treatment of TED. The "Age of Surgical Heroism" spans the time from 1888 to 1979 during which the pioneers of orbital decompression developed lateral orbitotomy, transcranial decompression, paranasal sinus decompression, and transantral decompression despite an incomplete understanding of the pathophysiology of both TED and a limited ability to non-invasively assess their patients. The "Age of Surgical Refinement" dawned with the development of computed tomography and represents the years 1979-2000. During this time, the "swinging eyelid" approach for two- and three-wall decompressions was introduced, a combined orbital-extradural four wall decompression procedure was developed, fat decompression was explored, and endoscopic decompression techniques were advanced. At the beginning of the 21st century, our understanding of the orbital pathophysiology of TED evolved significantly. Clinicians recognized the age-related phenotype of TED based largely on the relative contribution of extraocular muscle enlargement vs. orbital fat expansion. The "Modern Age" of Customized Orbital Decompression features both "medical decompression" during the active phase of TED and, in the stable phase, customized surgical plans incorporating individual patients' anatomy, orbital pathology, and surgical goals that collectively maximize therapeutic benefit while minimizing therapeutic morbidity.