Management of patients with dysthyroid optic neuropathy treated with intravenous corticosteroids and/or orbital decompression surgery

Three-dimensional soft tissue reconstruction and volume measurement used for the diagnosis of dysthyroid optic neuropathy

PURPOSE

Dysthyroid optic neuropathy (DON) leads to vision loss. This study aimed to investigate a new method that can directly evaluate the change in muscle cone inner volume (MCIV) and distinguish DON orbits from non-DONs.

MATERIALS AND METHODS

This study included 54 patients (108 orbits) who were diagnosed with thyroid eye disease and treated at the Beijing Tongren Hospital between December 2019 and September 2021. The extraocular muscle volume (EOMV), orbital fat volume (OFV), and bony orbit volume (BOV) of the patients were measured using three-dimensional reconstruction. MCIV was measured using artificially defined boundaries. The associations between these volumes and clinical indicators were studied, and the diagnostic efficacy of these volumes for DON was described using receiver operating characteristic (ROC) curves.

RESULTS

The ROC curve showed that the area under the curve of MCIV/BOV (%) combined with EOMV/BOV (%) reached 0.862 (p < 0.001), with a sensitivity of 85.7% and a specificity of 76.1%.

CONCLUSION

The combination of MCIV/BOV (%) and EOMV/BOV (%) is a good indicator for the diagnosis of DON, which aids in the early detection and intervention of DON.

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.

Outcomes of Patients With Dysthyroid Optic Neuropathy Treated With Intravenous Corticosteroids and/or Orbital Decompression Surgery: A Systematic Review and Meta-analysis

CONTEXT

The level of evidence is low for the treatment of patients with dysthyroid optic neuropathy (DON) and there is no consensus on the treatment of DON with intravenous high-dose glucocorticoids (ivGC) or direct surgical decompression.

OBJECTIVE

To compare the efficacy of glucocorticoid treatment and orbital decompression (OD) in DON.

DATA SOURCES

PubMed, EMBASE, and Cochrane Library were searched along with other sources.

STUDY SELECTION

A total of 17 studies met the inclusion criteria.

DATA EXTRACTION

Standard methodological guidance of the Cochrane Handbook was used and data were independently extracted by multiple observers. The primary outcomes were the improvement of best corrected visual acuity (ΔBCVA). Secondary outcomes were proptosis reduction, change in diplopia, visual field defects, and intraocular pressure (IOP).

DATA SYNTHESIS

The ΔBCVA in the ivGC + OD group was improved 0.26 LogMAR more than in the ivGC group (P = .007). The ΔBCVA in the OD group was better than in the ivGC group (P = .008). Posttreatment proptosis in the ivGC + OD and OD groups were improved further by 3.54 mm and 3.00 mm, respectively, than in the ivGC group (P < .01). The mean deviation (MD) in the ivGC + OD group was improved by an additional 5.33 dB than in the ivGC group (P = .002). The IOP in the ivGC + OD group was improved further than in the ivGC group (P = .03).

CONCLUSIONS

Based on the results of the present meta-analysis, OD or ivGC + OD may be more effective in improving BCVA and MD and reducing proptosis compared with ivGC. Compared with ivGC alone, ivGC + OD is more effective in improving IOP than ivGC. Although this study improves the hierarchy of evidence in the treatment of DON, additional randomized controlled trials are needed to confirm this conclusion.

Dysthyroid optic neuropathy: emerging treatment strategies

PURPOSE

Dysthyroid optic neuropathy (DON) is a rare sight-threatening complication of Graves' disease. First-line treatment for DON consists of high-dose intravenous methylprednisolone (ivMP), followed by immediate orbital decompression (OD) if the response is poor or absent as recommended by the 2021 European Group on Graves' orbitopathy guidelines. The safety and efficacy of the proposed therapy have been proven. However, consensus regarding possible therapeutic options for patients with contraindications to ivMP/OD or resistant form of disease is missing. This paper aims to provide and summarize all available data regarding possible alternative treatment strategies for DON.

METHODS

A comprehensive literature search within an electronic database was performed including data published until December 2022.

RESULTS

Overall, 52 articles describing use of emerging therapeutic strategies for DON were identified. Collected evidence indicates that biologics, including teprotumumab and tocilizumab, may be considered as an important possible treatment option for DON patients. Rituximab should be avoided in DON due to conflicting data and risk of adverse events. Orbital radiotherapy could be beneficial for patients with restricted ocular motility classified as poor surgical candidates.

CONCLUSION

Only a limited number of studies have been dedicated to the therapy of DON, mostly retrospective with a small sample size. Clear criteria regarding diagnosis and resolution of DON do not exist, which restricts comparison of therapeutic outcomes. Randomized clinical trials and comparison studies with long-term follow-ups are necessary to verify the safety and efficacy of each therapeutic option for DON.

Thyroid-associated ophthalmopathy: Using diffusion tensor imaging to evaluate visual pathway microstructural changes

Objective

The aim of this study was to determine whether the visual pathway is affected by thyroid-associated ophthalmopathy (TAO) before the development of dysthyroid optic neuropathy (DON) with diffusion tensor imaging (DTI).

Materials and methods

Fifty-seven TAO patients (22 mild, 35 moderate-severe TAO) and 30 healthy controls (HCs) were included. The DTI parameters of the lateral geniculate (LG) and optic radiation (OR) were measured. A full ophthalmic examination such as intraocular pressure, exophthalmos, and visual acuity was performed. Clinical activity scores (CAS) were also calculated. One-way ANOVA and Pearson's correlation were carried out. A binary logistic regression was used to identify variables that can diagnose TAO.

Results

Moderate-severe TAO patients showed significantly lower fractional anisotropy (FA) and higher mean diffusivity (MD) than HCs for both LG and OR (p &lt; 0.05). FA of OR was negatively correlated with CAS and intraocular pressure (p &lt; 0.05). Multivariate analysis showed that FA of LG and FA of OR were a significant predictor for the diagnosis TAO.

Conclusion

Diffusion tensor imaging parameters of the visual pathway were significantly altered in moderate-severe TAO patients. The FA of LG, in particular, can be used as a sensitive imaging biomarker for assessing subclinical visual pathway damage in TAO.