Peripapillary and Macular Vessel Density in Dysthyroid Optic Neuropathy: An Optical Coherence Tomography Angiography Study

Graves ophthalmopathy a neglected comorbidity of graves' disease; a detailed investigation and management of sixty-eight patients in a tertiary healthcare center

PURPOSE

To compare the measurements of macular thickness, intraocular pressure and RNFL and hormone parameters before and after antithyroid therapy in patients with Graves' Ophthalmopathy (GO).

METHODS

A prospective observational study conducted at a tertiary care center. Patients with GO were included and scored (Clinical Activity Score, CAS) according to EUGOGO guideline. The participants underwent extensive ophthalmological examinations including intraocular pressure measurements with Goldmann applanation tonometry and RNFL with macular thickness evaluations via optical coherence tomography (OCT). Baseline and follow-up (24 weeks) hormone parameters including free T3, free T4, Thyroid stimulating hormone (TSH), Thyroid receptor autoantibodies (TRAbs) and intraocular measurements (RNFL, macular thickness, intraocular pressure) were performed and compared in the current study.

RESULTS

Comparisons of baseline and follow-up biochemical parameters TSH, fT3, fT4, TRAbs, anti-TPO (p < 0.001). Although baseline score of CAS was mildly increased in all patients (0.5 ± 0.8 vs. 0.1 ± 0.4, p < 0.001) but it was significantly decreased after the antithyroid therapy. Mean intraocular pressure (14.9 ± 2.8 vs. 14.2 ± 1.9), RNFL (100.2 ± 9.05 vs. 99.9 ± 8.7) and macular thickness (274.7 ± 42.9 vs. 271.2 ± 43.3) were similar between baseline and after antithyroid therapy. And baseline RNFL measurements showed significant negative correlation with serum baseline TRAbs, antiTPO, fT3, fT4 (p < 0.05).

CONCLUSION

Baseline serum fT3, fT4 and TRAbs in patients with Graves' Disease levels may be the prognostic factors in the evaluation of affecting intraocular structure, especially Retinal Nerve Fiber Layer, in patients with GO.

Retinal and Choroidal Alterations in Thyroid-Associated Ophthalmopathy: A Systematic Review

Thyroid-associated ophthalmopathy (TAO), or Graves' orbitopathy (GO), is a complex autoimmune disorder affecting orbital tissues, often leading to vision-threatening complications such as dysthyroid optic neuropathy (DON). In this systematic review, conducted following PRISMA guidelines, 22 studies were evaluated to investigate the role of optical coherence tomography (OCT) in assessing retinal and choroidal changes in TAO. Parameters such as the retinal nerve fiber layer (RNFL), ganglion cell complex (GCC), ganglion cell layer (GCL), and choroidal thickness were analyzed. RNFL changes varied by disease severity, with significant thinning in DON due to nerve fiber loss and thickening in early DON due to optic disk edema. Subfoveal choroidal thickness (SFCT) was consistently higher in active TAO, correlating positively with the clinical activity score (CAS) and proptosis, suggesting its role as a marker of disease activity. Subgroup analysis revealed that spectral-domain OCT (SD-OCT) was the most sensitive for detecting retinal changes. The findings highlight the effectiveness of OCT in detecting minor retinal and choroidal alterations in TAO. However, the variability of study designs, as well as the lack of longitudinal data, limits the ability to draw broad conclusions. Further standardized, long-term investigations are required to properly understand OCT's diagnostic and prognostic value in TAO.

Increased choroidal stromal area in patients with active Graves' ophthalmopathy based on binarisation method of optical coherence tomographic images

OBJECTIVE

To investigate the change in choroidal components of patients with Graves' ophthalmopathy (GO) with different degrees of disease activity and severity by using the image binarisation method of optical coherence tomography (OCT).

METHODS

This cross-sectional study included 151 eyes of 90 patients with GO. Patients were grouped according to the clinical activity score (CAS) and disease severity. Total choroidal area (TCA), luminal area, stromal area (SA) and choroidal vascularity index (CVI) were acquired by image binarisation of the OCT. Ocular parameters between groups were compared using generalised estimating equations, accounting for intereye correlation and adjusting for relevant factors.

RESULTS

As for the included eyes, 104 eyes were inactive GO and 47 eyes were active GO. Local choroidal thicknesses were thicker in active GO than in inactive GO. TCA and SA were significantly larger in active GO than in inactive GO group (3.44±0.91 mm2 vs 3.14±0.88 mm2, p=0.046; 1.16 (1.03-1.50) mm2 vs 1.10 (0.96-1.27) mm2, p=0.002, respectively). CAS was positively correlated with TCA (r=0.171, p=0.036) and SA (r=0.172, p=0.035), and negatively associated with CVI (r=-0.174, p=0.032). In multiple regression models, age, diopter and intraocular pressure (IOP) exhibited significant correlations with the SA (β=-0.006, p=0.010; β=0.076, p<0.001; β=0.015, p=0.010, respectively).

CONCLUSIONS

Thickened choroid was observed in active GO compared with inactive GO. The proportional increase of SA was augmented as the disease activity progressed. Age, diopter and IOP were independent factors that affected choroidal area and components in patients with GO. Multicentre prospective cohort studies with a large sample size are still needed.

Retinal perfusion related to visual field within the same asymmetric thyroid-associated ophthalmopathy

PURPOSE

To quantify interocular differences in the retinal microvasculature between disparate eyes and explore associations between the retinal microvasculature and visual field abnormalities within the same asymmetric thyroid-associated ophthalmopathy (TAO) patients.

METHODS

Within the same asymmetric TAO eye, the eye with a severer visual field abnormality (based on the mean deviation [MD]) was considered a severe eye, and the fellow eye was considered mild. The densities of radial peripapillary capillary (RPC) and superficial retinal capillary plexuses (SRCP) were determined using optical coherence tomography angiography. Interocular differences in RPC and SRCP densities were analyzed. A generalized estimating equation (GEE) was used to form a predictive model for visual field abnormalities. Pearson's correlation was used to show the correlation between MD and the densities of RPC and SRCP.

RESULTS

In 57 asymmetric TAO patients, the global RPC density in severe eyes was lower than that in mild eyes (P < 0.001), but there was no significant difference in SRCP density between the two groups (P = 0.114). In a multivariate GEE model with MD as the outcome, MD was associated only with global RPC density (coefficient β=0.327, P < 0.001). The global RPC density was correlated with MD (r = 0.360, P = 0.003) in severe eyes, but not in mild eyes (r = 0.179, P = 0.092). No significant correlation was observed between global SRCP density and MD in either group (Both P > 0.05).

CONCLUSIONS

RPC density decreased significantly and correlated with visual field abnormalities in severe eyes of TAO patients. Alterations in RPC density may contribute to visual field abnormalities in TAO eyes.

Evaluation of lamina cribrosa and peripapillary vascular density in thyroid orbitopathy and effect of intravenous methylprednisolone therapy

OBJECTIVE

To evaluate optic nerve head changes in patients with thyroid orbitopathy (TO) and investigate the effects of intravenous methylprednisolone (IV MTP) on these changes.

METHODS

Eighty-two eyes of 41 patients with TO with and without dysthyroid optic neuropathy (DON) and 40 eyes of 40 healthy control subjects were included in the study. Lamina cribrosa thickness (LCT) and depth (LCD) measurements, peripapillary retinal nerve fibre layer thickness (RNFLT), and radial peripapillary capillary vascular density were measured using optical coherence tomography and optical coherence tomography angiography. Visual field examination and proptosis were evaluated. Patients with DON and active non-DON received IV MTP for 12 weeks, and the effect of this treatment was evaluated.

RESULTS

Peripapillary vascular density decreased in patients with DON compared with the other groups (p < 0.001 for all); there was no difference in the total, superior hemi-sector, and inferior hemi-sector of the RNFLT between the groups. LCT was decreased in the TO group (p < 0.001). After IV MTP treatment, the LCT and best-corrected visual acuity were increased. Thyroid-stimulating hormone receptor antibody levels, intraocular pressure, the superior hemi-sector of the RNFLT, and proptosis were decreased compared with the control subjects (p = 0.012, p = 0.008, p = 0.043, and p < 0.001, respectively).

CONCLUSIONS

The RNFLT may not always increase in DON. Lamina cribrosa morphology may change in patients with TO. IV MTP therapy has a positive effect on the LCT but not on radial peripapillary capillary vascular density or LCD.

Balanced medial-lateral wall vs selective 3-wall orbital decompression for sight-threatening Graves's orbitopathy: a clinical retrospective cohort study from 2016 to 2022

PURPOSE

Although urgent orbital decompression surgery for sight-threatening Graves' orbitopathy unresponsive to available medical treatments continues to evolve, post-operative new-onset or worsened pre-operative strabismus or diplopia remains a significant complication. At present, the optimal surgical technique remains debatable. Here, we sought to compare long-term outcomes after balanced medial-lateral wall versus selective 3-wall decompression as an urgent treatment for unresponsive sight-threatening GO.

METHODS

This retrospective study examined the post-operative outcome of 102 eyes (57 patients) that underwent urgent orbital decompression for sight-threatening GO. Treatment effectiveness was measured by visual acuity, proptosis, perimetry, and strabismus/diplopia, while fundus findings were detected by fundus color photography and optical coherence tomography and followed up for more than 12 months.

RESULTS

Fifty-seven patients (102 orbits) with an average age of 52.7 ± 10.2 years were evaluated. Balanced medial-lateral wall (BMLW-OD) or selective 3-wall decompression(S3W-OD) were performed in 54 and 48 eyes, respectively. Twelve months after orbital decompression, all parameters significantly improved in both groups, including best-corrected visual acuity (BCVA), mean defect of visual field (VF-MD), pattern standard deviation of visual field (VF-PSD), and proptosis (all P < 0.01). However, new-onset esotropia occurred in 25.8% and 3.8% of patients who underwent BMLW-OD surgery or S3W-OD, respectively. Moreover, 6.5% and 38.5% of patients improved after decompression in the medial-lateral wall decompression group and the selective 3-wall decompression group, respectively.

CONCLUSIONS

We demonstrated that S3W-OD provides a lower rate of new-onset strabismus/diplopia as compared with BMLW-OD surgery, while still allowing for satisfactory visual outcomes.

TRIAL REGISTRATION NUMBER

 : NCT05627401. Date of registration: November 25, 2022.

Optical coherence tomography angiography in thyroid associated ophthalmopathy: a systematic review

PURPOSE

To evaluate the evidence for alterations of blood flow, vascular and perfusion densities in the choroid, macula, peripapillary region, and the area surrounding the optic nerve head (ONH) in patients with thyroid-associated ophthalmopathy (TAO) based on changes of OCTA parameters.

METHODS

A systematic review of Pubmed, Google Scholar, Scopus, WOS, Cochrane, and Embase databases, including quality assessment of published studies, investigating the alterations of OCTA parameters in TAO patients was conducted. The outcomes of interest comprised changes of perfusion and vascular densities in radial peripapillary capillary (RPC), ONH, superficial and deep retinal layers (SRL and DRL), choriocapillaris (CC) flow, and the extent of the foveal avascular zone (FAZ).

RESULTS

From the total of 1253 articles obtained from the databases, the pool of papers was narrowed down to studies published until March 20th, 2024. Lastly, 42 studies were taken into consideration which contained the data regarding the alterations of OCTA parameters including choriocapillary vascular flow, vascular and perfusion densities of retinal microvasculature, SRL, and DRL, changes in macular all grid sessions, changes of foveal, perifoveal and parafoveal densities, macular whole image vessel density (m-wiVD) and FAZ, in addition to alterations of ONH and RPC whole image vessel densities (onh-wiVD and rpc-wiVD) among TAO patients. The correlation of these parameters with visual field-associated parameters, such as Best-corrected visual acuity (BCVA), Visual field mean defect (VF-MD), axial length (AL), P100 amplitude, and latency, was also evaluated among TAO patients.

CONCLUSION

The application of OCTA has proven helpful in distinguishing active and inactive TAO patients, as well as differentiation of patients with or without DON, indicating the potential promising role of some OCTA measures for early detection of TAO with high sensitivity and specificity in addition to preventing the irreversible outcomes of TAO. OCTA assessments have also been applied to evaluate the effectiveness of TAO treatment approaches, including systemic corticosteroid therapy and surgical decompression.

Artificial Intelligence-based quantitative evaluation of retinal vascular parameters in thyroid-associated ophthalmopathy

PURPOSE

Thyroid-associated ophthalmopathy (TAO) may result in increased metabolism and abnormalities in microcirculation. The fractal dimension (Df) of retinal vessels has been shown to be related to the pathology of a number of ophthalmic disorders, but it hasn't been investigated in TAO.

METHODS

We analyzed 1078 participants aged 18 to 72 (548 healthy volunteers and 530 TAO). Images were captured using a non-mydriatic 45-degree fundus camera. Baseline retinal characteristics, such as vessel width, tortuosity, and Df were measured using semiautomated software from fundus images. The average retinal parameters were compared between the two groups. The receiver operation curve (ROC) was used to assess the diagnostic efficacy of various retinal vascular parameters for TAO.

RESULTS

Despite controlling for potential confounding variables, Df, vessel width, and tortuosity significantly increased in TAO compared to healthy volunteers. Compared to active TAO, patients in the inactive phase had a larger retinal venous caliber (p < 0.05), but there was no difference in Df or arterial caliber. Moderate and severe cases had a higher Df compared with mild cases (EUGOGO guidelines). The area under the ROC for Df, tortuosity, and vascular caliber in the diagnosis of TAO was 0.904 (95% CI: 0.884-0.924), 0.638 (95% CI: 0.598-0.679), and 0.617 (95% CI: 0.576-0.658), respectively.

CONCLUSIONS

Due to its accessibility, affordability, and non-invasive nature, retinal vascular Df may serve as a surrogate marker for TAO and might be used to identify severe cases. With relatively high diagnostic performance, the Df is of some utility for the detection of TAO.

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.

Comparison of macular and optic disc vessel density in thyroid orbitopathy: a comparative octa study

PURPOSE

To determine the microvascular and structural changes in the peripapillary and macular areas observed in patients with active thyroid orbitopathy(TO) before and after steroid treatment and compare with inactive TO and the control group by optical coherence tomography angiography (OCTA).

MATERIAL AND METHOD

This cross-sectional study included 34 eyes of 17 active TO patients, 108 eyes of 54 inactive TO patients, and 60 eyes of 30 healthy controls. Central macular thickness (CMT), ganglion cell layer-inner plexiform layer (GCL-IPL) thickness, central choroidal thickness (CCT), retinal nerve fiber layer (RNFL) thickness, choroidal thickness in the peripapillary region, superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris vessel densities were determined by OCTA in before and after 12-week steroid treatment of active TO cases, inactive TO and control groups.

RESULTS

Between the three groups in macula OCTA, a statistically significant difference was observed in the inferior and nasal quadrants in SCP (all p = 0.01) and only in the temporal quadrant choriocapillaris (p = 0.005). In peripapillary OCTA, a statistically significant difference was found only in the central choriocapillaris (p = 0.03). In the comparison of the active group before and after treatment, there was a statistically significant decrease in CMT and CCT; a statistically significant increase was observed in GCL-IPL (all p < 0.01). There was a statistically significant decrease in SCP and DCP only in the central (all p < 0.01). There was a statistically significant increase was found in the lower quadrant macular SCP vessel density and mean macular DCP in post-treatment measurements (p = 0.01 and p = 0.03, respectively). Peripapillary SCP and DCP vessel density was increased after treatment (p < 0.01).

CONCLUSION

Active TO group had lower vessel density than inactive group and after treatment, vessel density was increased. Non-invasive quantitative analysis of retinal and optic disc perfusion using OCTA could be useful in early treatment before complications occur and monitoring patients with TO.

Changes in retinal nerve fiber layer, ganglion cell complex, and ganglion cell layer thickness in thyroid eye disease: A systematic review

Thyroid eye disease (TED) is characterized by progressive orbital inflammation. In severe cases, it can lead to dysthyroid optic neuropathy (DON), involving death of retinal ganglion cells and permanent vision loss. Imaging with optical coherence tomography (OCT) has enabled noninvasive examination of the structural impact of the disease, including of the retinal nerve fiber layer (RNFL), the ganglion cell layer (GCL), and the inner plexiform layer (IPL). In this study, we systematically review 20 studies (897 patients, 1430 eyes) to evaluate changes in retinal thickness in patients with TED, stratified by severity. Most studies found a decrease in thickness in peripapillary RNFL (pRNFL), non-pRNFL, combined RNFL/GCL/IPL, or combined GCL/IPL when comparing patients with DON to healthy controls or to patients without DON. However, results were equivocal regarding differences between non-DON TED patients and controls. In addition, several studies reported a postoperative decrease in pRNFL thickness after orbital decompression surgery. Future studies examining OCT changes of retinal thickness along with disease progression are needed to assess the potential of OCT in diagnosis and management of patients with TED.

Optical coherence tomography and shear wave elastography findings in Graves ophthalmopathy

PURPOSE

The main feature of Graves ophthalmopathy (GO) is revealed by determining the activity and severity of the disease. We aimed to evaluate the use of imaging methods can also provide additional information about the severity of this disease.

METHODS

Optical coherence tomography (OCT) and shear wave elastography (SWE) findings were compared in 32 patients with mild GO group and in the healthy control group. Measuring for TSH receptor antibody (TRAb) serum level is used third-generation assay.

RESULTS

In Graves group, optic nerve sheath diameter (ONSD) values were increased in both eyes (p < 0.001, p < 0.001). SWE measurements showed a significant increase both eye optic nerve (ON) and right eye soft tissue elasticity values in GO group (p < 0.001, p < 0.001, p < 0.001, respectively). There was a significant thinning in left temporal retinal nerve fiber layer (RNFL) thickness and left RNFL peripapillary thickness in GO group (p < 0.001, p < 0.025, respectively). There was a correlation between left eye OCT and SWE findings. Also, there was a significant difference between the median left eye ON and soft tissue elasticity results in the TRAb-positive GO group (p = 0.049, p = 0.048, respectively).

CONCLUSION

SWE measurements showed a significant increase both eyes ONSD, ON and right eye soft tissue elasticity values in GO group. GO group was significant thinning in some left eye regions in OCT measurements. There was a correlation between left eye OCT and SWE findings. In addition to clinical activity score and TRAb, SWE and OCT can be used to monitor in patients with GO.

Macular blood flow changes in dysthyroid optic neuropathy after high-dose intravenous pulse methylprednisolone (IVMP)

OBJECTIVE

To investigate the changes in macular vessel density (VD) of the superficial layer of retina (SLR) and deep layer of retina (DLR) in dysthyroid optic neuropathy (DON) after high-dose intravenous pulse methylprednisolone (IVMP).

MATERIALS AND METHODS

Eighteen DON patients (29 eyes) who completed high-dose IVMP and 16 healthy individuals (32 eyes) were enrolled in this study. Optical coherence tomography angiography (OCTA) image analysis and comprehensive ophthalmic examinations were performed, including the SLR macular whole-image VD (SLR-mwiVD) and DLR-mwiVD, best-corrected visual acuity (BCVA), the mean deviation of visual field (VF-MD), pattern standard deviation of visual field (VF-PSD) and the other parameters.

RESULTS

The SLR-mwiVD (41.39 ± 4.71 vs. 48.13 ± 3.68, p < 0.001) and DLR-mwiVD (40.77 ± 5.85 vs. 49.14 ± 7.02, p < 0.001) were decreased in DON compared to control eyes. After IVMP, visual function parameters were improved, and SLR-mwiVD (49.41 ± 3.18, p < 0.001) and DLR-mwiVD (50.41 ± 4.04, p < 0.001) were increased in the DON group compared to pretreatment. The increased SLR-mwiVD and DLR-mwiVD were significantly correlated with improvements in BCVA (Log MAR: from 0.62 ± 0.49 to -0.01 ± 0.03, p < 0.001), VF-MD (from - 6.89 ± 2.89 dB to - 1.75 ± 1.29 dB, p < 0.001) and VF-PSD (from 4.38 ± 2.52 dB to 2.32 ± 1.64 dB, p < 0.001).

CONCLUSION

The increase in macular VD was significantly correlated with the improvement in visual function in DON after IVMP. Macular VD changes on OCTA may be a useful indicator for the response in DON after IVMP.

3.0 T multi-parametric MRI reveals metabolic and microstructural abnormalities in the posterior visual pathways in patients with thyroid eye disease

Introduction

We aim to explore the microstructural and metabolic changes in visual pathways in patients with thyroid eye disease (TED) using 3T multi-parametric MRI.

Methods

Thirty-four TED patients (inactive group = 20; active group = 14; acute group = 18; chronic group = 16) and 12 healthy controls (HC) were recruited from November 2020 to July 2021. Proton magnetic resonance spectroscopy (1H-MRS), glutamate chemical exchange saturation transfer (GluCEST) and diffusion kurtosis imaging (DKI) were performed on 3.0T MR scanner. Data analysis and group comparisons were performed after MR data processing.

Results

As compare to HC group, the levels of total choline (tCh) in optic radiation (OR) in active group ([1.404 ± 0.560] vs. [1.022 ± 0.260]; p < 0.05), together with tCh ([1.415 ± 0.507] vs. [1.022 ± 0.260]; p < 0.05) in OR in acute group were significantly increased. Glutamine (Gln) levels were higher in OR in the chronic group than those in HCs and were positively correlated with the levels of thyroglobulin antibody (TgAb), thyroid peroxidase antibody (TPOAb), free triiodothyronine (FT3) and FT4 in chronic group. Glutamate (Glu) levels by 1H-MRS did not show significant differences between any two groups. Interestingly, MTRasym (3.0 ppm) was higher in OL in inactive group, active group, acute group and chronic group than those in HCs, and was positively correlated with Glu levels in OL in 1H-MRS. Fractional anisotropy (FA) values from DKI in OR in acute group were significantly lower than those in HCs.

Discussion

Our initial study demonstrate that GluCEST performs better than 1H-MRS to monitor Glu alterations in visual pathway in TED patients. Changes of brain glutamine levels in TED patients are closely related to their associated hormones alterations, indicating that disease injury status could be reflected through non-invasive metabolites detection by brain 1H-MRS. FA is the most sensitive DKI index to reveal the visual pathway impairment in TED patients. Altogether, our study revealed that 3T multiparametric MR techniques are useful to demonstrate metabolic and microstructural alterations in visual pathways in TED patients. We found that damage to visual pathways occurs in mild TED cases, which not only offers a new approach to the diagnosis of dysthyroid optic neuropathy, but also demonstrates neuropathy in TED is a gradual and continuous spatio-emporal progression.

Assessment of retinal and choroidal vessel density and nerve fibre layer thickness changes after orbitotomy in patients with severe non-active thyroid orbitopathy: a prospective study

PURPOSE

To evaluate the optical coherence tomography angiogram changes in non-active severe thyroid-related ophthalmopathy patients after cosmetic bone decompression.

METHODS

Eighteen patients (25 eyes) with severe not active not compressive (NANC) TED who were candidates for decompression surgery for cosmetic reasons were included in this study, and a 3 × 3 mm macular scan was used to measure vessel density and RNFL thickness. Whole macular vessel density in its superficial, deep and choriocapillaris layers was evaluated. The following data were extracted for each of layers: superior and inferior hemispheres, fovea, parafoveal vessel density, its superior and inferior hemispheres, and temporal, superior, nasal and inferior quadrant.

RESULTS

The mean RPC increased postoperatively, which was statistically significant in small vessels of peripapillary area (p-value = 0.045). The mean RNFL thickness decreased after surgery and it was statistically significant in the peripapillary (p-value = 0.032) and Inferior-Hemifield area (p-value = 0.036). The choriocapillaris changes were significant in Superior-Hemifield (p-value = 0.031) and Fovea (p-value = 0.03).

CONCLUSION

Thyroid-associated orbitopathy patients have a tendency to decrease vascular density and correlated with disease activity more than stage of orbitopathy. There was not a strong and even discrepant result in linkage of RNFL thickness and other optic nerve function tests and TED patient status and it is needed to do studies with more epidemiologic power and same methodology of study to be more comparable.

OCT and OCTA in dysthyroid optic neuropathy: a systematic review and meta-analysis

PURPOSE

To explore the current research about the role of optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in dysthyroid optic neuropathy (DON).

METHODS

Studies in the literature that focused on OCT, OCTA and DON were retrieved by searching PubMed, EMBASE, Cochrane databases and Clinical Trial before 20 June 2023. The methodological quality was assessed using the Newcastle-Ottawa scale. The quantitative calculation was performed using Review Manager V.5.3.

RESULTS

Twelve studies met the eligibility criteria and were included. DON group presented lower macular ganglion cell complex in the overall, superior and inferior hemifields compared with the non-DON group. Furthermore, the ganglion cell layer and inner plexiform layer in DON group was thinner in contrast to the non-DON group. The optic nerve head vessel density was lower in the DON group than that in the non-DON group. A reduction of radial peripapillary capillary vessel density could be seen in the DON group than the non-DON group in overall, inside disc, peripapillary, superior-hemifield, temporal and nasal. Besides, the macular superficial retinal capillary layer of non-DON and DON is lower than the healthy control group.

CONCLUSIONS

This study supported the potential value of OCT and OCTA metrics as novel biomarkers of DON. Ophthalmologists should comprehensively consider the retinal structure and microvasculature in dealing with DON.

ETHICS AND DISSEMINATION

This systematic review included data from published literature and was exempt from ethics approval. Results would be disseminated through peer-reviewed publication and presented at academic conferences engaging clinicians.

PROSPERO REGISTRATION NUMBER

CRD42023414907.

Secondhand smoke exposure and ocular health: A systematic review

The toxicology of secondhand smoke (SHS), along with the harm of its exposure to human health, has been generally acknowledged; however, specific evidence is lacking on the association between SHS exposure and ocular health. In this systematic review (PROSPERO registration number: CRD42022247992), we included 55 original articles published by 12 May 2023, which dealt with SHS exposure and ocular disorders, such as eye irritation, conjunctivitis, dry eye diseases, uveitis, myopia, astigmatism, contact lens discomfort, age-related macular degeneration, glaucoma, and thyroid eye disease that addressed the ocular neurovascular structures of the macular, retinal nerve fiber layer, choroid, and corneal biomechanical parameters. We found compelling correlational evidence for eye irritation, conjunctivitis, and dry eye symptoms-supporting that SHS exposure was positively associated with inflammatory and allergic changes in the eyes. Yet, evidence about the associations between SHS exposure and other ocular disorders, structures, and parameters is still limited or controversial. Given the limitations of existing literature, more investigations with high quality and rigorous design are warranted to elucidate the potentially harmful effects of SHS exposure on ocular health.

Automated evaluation of parapapillary choroidal microvasculature in thyroid eye disease

PURPOSE

The purpose of the study was to investigate the parapapillary choroidal microvasculature in thyroid eye disease (TED) using optical coherence tomography angiography (OCTA).

METHODS

Only one eye of each subject was included in the study. Patients with TED and controls were included in the study. Participants were divided into three groups: control, inactive TED (ITED) and active TED (ATED). OCTA scans of the optic discs were obtained in a 4.5 × 4.5-mm rectangular area. Radial peripapillary capillary (RPC) density and peripapillary retinal nerve fibre layer (pRNFL) thickness were automatically calculated by the device software. Parapapillary choroidal microvasculature (PPCMv) density was automatically calculated using MATLAB software.

RESULTS

Forty-one patients with TED and 40 controls were included in the study. RPC density was significantly decreased in the ATED and dysthyroid optic neuropathy (DON) group compared to the controls and ITED group. There was significant increase in pRNFL in the ATED group. PPCMv density increased in the ATED group compared to the controls in whole ring area. The RPC density was significantly correlated with the TSHr Ab level (r < - 0.396, p < 0.001). Clinical activity score correlated positively with PPCMv density (r = 0.349, p = 0.001) but negatively with RPC density (r = - 0.321, p = 0.004).

CONCLUSION

Changes in peripapillary microvascular perfusion may play a role in the development of DON. As the severity of TED increases with clinical activity, so do the changes observed in peripapillary parameters. The decrease in RPC density may be due to compression caused by optic disc oedema, which may result in reduced blood flow. The increase in PPCMv density may be related to factors such as orbital congestion.

HbA1c: an independent risk factor for dysthyroid optic neuropathy

Background

We aimed to explore the frequencies of islet β-cell autoantibodies and insulin resistance (IR) in thyroid-associated ophthalmopathy (TAO) and identify specific diabetes mellitus (DM) indicators as early predictors for dysthyroid optic neuropathy (DON).

Methods

Ninety-eight TAO patients (57 DON and 41 non-DON patients) and 48 healthy control (HC) participants were recruited for this prospective cross-sectional study. Serum thyroxine, serum thyroid autoantibodies, serum humoral immune markers against islet β-cell, fasting plasma glucose (FPG), fasting serum insulin (FINS), fasting c-peptide (FCP), and glycosylated hemoglobin A1 (HbA1c) were measured. Logistic regression analysis was used to evaluate the correlation of patients' age, body mass index (BMI), FPG, HbA1c, and related indexes of islet β-cell function to the occurrence of DON.

Results

The DON group had higher FPG (P<0.001, 0.016) and HbA1c (P<0.0001, P<0.001) levels than the HC and non-DON groups. The homeostasis model assessment (HOMA)-IR level was the highest in the DON group (HC 2.15 ± 0.89, non-DON 2.41 ± 1.24, and DON 2.82 ± 2.65), while the HOMA-β level was the lowest (HC 101.8 ± 44.75%, non-DON 102.9 ± 54.61%, and DON 88.29 ± 52.75%), with no significant differences (P=1, P>0.05). On univariate analysis, age (P=0.006), BMI (P=0.022), history of steroid use (P=0.014), FPG (P=0.013), and HbA1c (P=0.001) levels were significantly associated with the presence/absence of DON. In addition, after adjusting for potential confounds, the HbA1c level was an independent factor associated with DON (P=0.009, OR=4.012).

Conclusions

HbA1c is an independent risk factor for DON. Given the interconnected link between thyroid dysfunction and DM, the use of HbA1c as a potential biomarker for DON warrants further investigation.

Optical coherence tomography angiography findings in pediatric patients with graves ophthalmopathy

PURPOSE

The aim of this study was to evaluate peripapillary, macular microvascular structure, and retinal nerve fiber layer (RNFL) thickness profile in children with Graves Ophthalmopathy (GO).

MATERIAL AND METHODS

Thirty-six eyes of 18 children with GO were prospectively compared with 40 eyes of 20-age and sex-matched controls. The severity and activity of the disease were evaluated according to the criteria of the European Group on Graves' Ophthalmopathy (EUGOGO) and Clinical Activity Score (CAS). After complete ophthalmologic and endocrinologic examination, all patients underwent optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) measurements. Retinal nerve fiber layer (RNFL) thickness, macular superficial capillary plexus (SCP), deep capillary plexus (DCP), foveal avascular zone (FAZ) area, acircularity index (AI) of the FAZ and peripapillary microvascular structure were analyzed.

RESULTS

The mean age was 12.1 ± 2.4 years in the GO group and 11.2 ± 2.6 years in healthy control group (p = 0.11). Duration of disease was 8.9 ± 4.2 months in the GO group. All patients in GO group had mild and inactive ophthalmopathy. In temporal inferior quadrant, RNFL thickness was significantly thinner in the GO group compared to the control group (p = 0.03). No significant difference was seen between groups both peripapillary and macular microvascular structure (all p > 0.05).

CONCLUSION

GO has no effect on optic nerve thickness, peripapillary and macular vascular parameters except inferior temporal RNFL in children.

Macular microvasculature in patients with thyroid-associated orbitopathy: a cross-sectional study

PURPOSE

The aim of this study was to evaluate macular blood flow in patients with thyroid-associated orbitopathy (TAO) as compared to healthy subjects. The inflammatory nature of the disease, as well as the vascular congestion caused by the increase in the volume of orbital soft tissue and extraocular muscles, rationalize the assessment of retinal blood flow changes in these patients.

METHODS

This is a cross-sectional study with the convenience sampling method. Macular flow density was assessed using optical coherence tomography angiography (OCTA) and compared between patients with TAO and healthy individuals. We also compared macular flow density in two subgroups of patients based on clinical activity score (CAS).

RESULTS

Eighty-five cases, including 30 healthy individuals and 55 patients with TAO, participated. The foveal avascular zone (FAZ) area was significantly larger in the patient group than in the control. Patients with active TAO with CAS 3 or more had significantly larger FAZ areas than those with CAS less than 3 (p = 0.04).

CONCLUSION

We showed that the FAZ area is larger in active TAO patients and can be considered a possible candidate feature for monitoring disease activity and thyroid-associated vasculopathy.

Utility of isolated-check visual evoked potential technique in dysthyroid optic neuropathy

PURPOSE

To analyze the utility of isolated-check visual evoked potential (icVEP) for discriminating between eyes with dysthyroid optic neuropathy (DON) and eyes with thyroid-associated ophthalmopathy (TAO) but not DON.

METHODS

Forty-three eyes with TAO but not DON (as non-DON), fifty-three eyes with DON, and sixty healthy eyes (as controls) were included. Comprehensive ophthalmic examinations, including best-corrected visual acuity, refraction, color vision test, intraocular pressure measurement, slit-lamp biomicroscopy, ophthalmoscopy, RAPD, exophthalmometry measurements, pVEP test, icVEP test, standard automated perimetry, and clinical activity score classification of TAO, as well as demographic information, were collected and analyzed.

RESULTS

In the DON group, the signal-to-noise ratio (SNR) value of icVEPs decreased significantly compared with that of the non-DON group as well as control (p < 0.05). The SNR values under 8%, 16% and 32% depth of modulation (DOM) were significantly negatively correlated with BCVA (p < 0.05, r =  - 0.9 ~  - 0.6), papilledema (Y/N) (p < 0.05, r =  - 0.8 ~ 0.4) and DON (Y/N) (p < 0.001, r =  - 0.7 ~  - 0.5). The 8% DOM of icVEP had the largest area under the receiver operating characteristic curve (AUC) (0.842) for discriminating DON from non-DONs. Meanwhile, decision curve analysis (DCA) showed that patients clinically benefit most from 8% DOM of icVEP. Furthermore, the 8% DOM of icVEP combing with papilledema (Y/N) and BCVA (Model 1) has significantly larger AUC than the 8% DOM of icVEP (p = 0.0364), and has better clinical benefit in DCA analysis.

CONCLUSIONS

The SNR of 8% DOM from icVEP may represent a significant ancillary diagnostic method for DON detection. Furthermore, icVEP combined with papilledema (Y/N) and BCVA should be considered as a diagnostic model in future clinical practice.

Optical coherence tomography and optical coherence tomography — angiography used in endocrine ophthalmopathy

The literature review presents the results of optical coherence tomography and optical coherence tomography — angiography used for Graves’ orbitopathy. The data on the thickness of the inner layers of the retina, microcirculation in the peripapillary and macular regions, parameters of the choroid, lamina cribrosa and extraocular muscles were analyzed as possible diagnostic criteria of the condition.

Preliminary Diffusion-Tensor Imaging Evidence for Trans-Synaptic Axonal Degeneration in Dysthyroid Optic Neuropathy Due to Thyroid-Associated Ophthalmopathy

BACKGROUND

The mechanism driving dysthyroid optic neuropathy (DON) is unclear. Diffusion-tensor imaging (DTI) allows for noninvasively assessing the microstructure of the entire visual pathway and may facilitate a better understanding of the mechanism of DON.

PURPOSE

To assess microstructural changes of the whole visual pathway and to investigate the potential mechanism of trans-synaptic damage（TSD） pathogenesis in DON with DTI.

STUDY TYPE

Cross-sectional.

POPULATION

Sixty-four patients with bilateral thyroid-associated ophthalmopathy (TAO), 30 with and 34 without DON, and 30 age- and sex-matched healthy controls (HCs).

FIELD STRENGTH/SEQUENCE

3 T/DTI (A single-shot diffusion-weighted echo-planar imaging sequence).

ASSESSMENT

Differences in DTI parameters including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) in each segment (optic nerve, tract, and radiation) of the entire visual pathway among the groups were compared. The parameters of visual evoked potentials (VEPs), visual field tests, and mean retinal nerve fiber layer (mRNFL) thickness on optical coherence tomography were also compared across patients.

STATISTICAL TESTS

Student's t-test, chi-square test; ANOVA with post-hoc testing, interclass correlation coefficient, and correlation analysis. Significance level: P < 0.05.

RESULTS

TAO patients with DON showed significantly reduced mRNFL thickness and abnormal VEPs. There was a tendency for gradually reduced FA and AD, and increased RD and MD from HCs, with non-DON to with DON in optic nerve and tract, statistically. For radiation, the RD and MD showed statistical increase, the AD and FA just showed numerical decrease (P = 0.119 and 0.059, respectively). For DON, the FA and MD of visual pathway segments showed correlations with abnormal VEPs.

DATA CONCLUSION

DTI may be a useful tool for detecting microstructural changes in the entire visual pathway in DON. The changes in RNFL thickness and DTI parameters suggested TSD as a potential pathogenic mechanism of DON.

EVIDENCE LEVEL

4 Technical Efficacy: Stage 5.

Retinal peripapillary microvasculature in indirect traumatic optic neuropathy predicted prognosis of endoscopic trans-ethmosphenoid optic canal decompression

PURPOSES

The purpose of this study is to quantify the alteration of retinal peripapillary microvasculature and structure in unilateral indirect traumatic optic neuropathy (ITON) and figure out predicted factors of visual improvement for ITON patients with endoscopic trans-ethmosphenoid optic canal decompression (ETOCD) after one month.

METHODS

Twenty healthy controls and 72 unilateral ITON patients were included. Optical coherence tomography angiography was used to analyse radial peripapillary capillary (RPC) density, peripapillary retinal nerve fibre layer (pRNFL) thickness, superficial retinal capillary plexus (SRCP) and deep retinal capillary plexus (DRCP) density. Associations between preoperative parameters and postoperative best-corrected visual acuity (BCVA) were determined. The receiver operating characteristic (ROC) curves were used to figure out predicted factors of visual improvement for ITON after ETOCD one month.

RESULTS

In ITON eyes, the preoperative global RPC density, pRNFL thickness and SRCP density were reduced compared with unaffected eyes (p ≤ 0.001). Multivariate linear regression showed that preoperative global RPC density (Standardized β = -0.273), SRCP density (Standardized β = -0.183), DRCP density (Standardized β = -0.098) and preoperative BCVA (Standardized β = 0.795) were associated with the postoperative BCVA (All p < 0.001). The area under the curve (AUC) of preoperative global RPC density to predict visual improvement after ETOCD was 0.816, while the AUCs of preoperative BCVA, global pRNFL thickness, SRCP and DRCP density were 0.575, 0.756, 0.516 and 0.615, respectively.

CONCLUSIONS

The alteration of peripapillary area, especially the reduced RPC density, occurred in ITON eyes. The preoperative RPC density was associated with postoperative BCVA and was shown to be highly predictive for visual improvement after ETOCD one month.

Reduced contrast sensitivity function correlated with superficial retinal capillary plexus impairment in early stage of dysthyroid optic neuropathy

BACKGROUND

To assess the accuracy of contrast sensitivity function (CSF) in detecting dysthyroid optic neuropathy (DON) at an early stage in thyroid-associated ophthalmopathy (TAO) patients and to examine potential factors that may be linked to early visual impairments in these individuals.

METHODS

A total of 81 TAO patients (50 non-DON and 31 DON), and 24 control subjects participated in the study. CSF was measured with the quick CSF (qCSF) method. Optical coherence tomography angiography (OCTA) images of the ganglion cell complex layer (GCCL), superficial and deep retinal capillary plexuses (SRCP and DRCP) in a 3 mm diameter area around the macula were evaluated.

RESULTS

Compared with the controls, the area under the log contrast sensitivity function (AULCSF) and SRCP density were significantly reduced in non-DON and DON patients (all P < 0.05). The GCCL thickness of the DON patients was thinner than that of the controls and non-DON patients (all P < 0.05). The AULCSF was significantly correlated with spherical equivalent refractive error, muscle index, SRCP density and GCCL thickness in TAO patients, respectively (all P < 0.05). However, stepwise multi-regression analysis showed that the AULCSF was only significantly correlated with SRCP density (P < 0.001). Receiver operating characteristic curve analysis showed that the AULCSF produced the most accurate discrimination between non-DON and DON patients from the controls (AUC = 0.831, 0.987, respectively; all P < 0.001).

CONCLUSIONS

CSF change in the early stage of DON is related to SRCP density. It can be an early indicator of visual impairments associated with DON in TAO patients.

Orbital and ocular perfusion in thyroid eye disease

Thyroid eye disease (TED) is characterized by enlargement of extraocular muscles, an increase in retrobulbar fat, orbital fibrosis, and fluctuations in plasma thyroid hormone levels in most patients, often associated with raised autoantibody titers. The occurrence of orbital space conflict compromises the orbital perfusion, unchecked progression of which results in irreversible loss of visual acuity and visual fields. The quantitative assessment of orbital perfusion can be done by measurement of blood flow velocities in the superior ophthalmic vein (SOV), ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery by color Doppler imaging. The retinal and choroidal microvasculature is studied by optical coherence tomography and optical coherence tomography angiography. The orbital and ocular perfusion fluctuates during the course of TED. Orbital congestion is reflected by the reduction or reversal of SOV flow and an increase in subfoveal choroidal thickness. The active phase is characterized by high blood flow velocities of the OA and CRA. The onset of dysthyroid optic neuropathy is associated with reduced arterial perfusion and reduction in parafoveal and peripapillary vascular density. Orbital decompression improves the SOV flow and decreases the resistivity index of CRA. Sequential evaluation of orbital hemodynamic changes can thus supplement the clinical scoring systems for monitoring and planning intervention in TED.

The Outcomes of Balanced Orbital Decompression for Dysthyroid Optic Neuropathy: Focusing on Choroiretinal Folds with and without Optic Disc Edema

Purpose

To assess the outcomes of balanced orbital decompression for chorioretinal folds (CRFs) with and without optic disc edema (ODE) in dysthyroid optic neuropathy (DON).

Method

A retrospective, interventional study was performed at Sun Yat-sen Memorial Hospital from April 2018 to November 2021. We collected the medical records of 13 patients (24 eyes) with DON and CRFs. Then, we divided them into the ODE group (15 eyes, 62.5%) and the non-ODE group (NODE group, 9 eyes, 37.5%). The valid ophthalmic examination parameters of 8 eyes in each group after balanced orbital decompression were compared at the 6-month follow-up.

Results

The mean best corrected visual acuity (BCVA, 0.29 ± 0.27) and visual field-mean deviation (VF-MD, -6.55 ± 3.71 dB) in the ODE group were significantly worse than those in the NODE group (0.06 ± 0.15 and -3.49 ± 1.56 dB; all p < 0.01). Six months after orbital decompression, all parameters were found to have significantly improved in both groups, including BCVA and VF-MD (all p < 0.05). Moreover, the improvement amplitude of BCVA (p = 0.020) in the ODE group was significantly greater than that in the NODE group. There was no difference in BCVA between the ODE group (0.13 ± 0.19) and the NODE group (0.10 ± 0.13). The disc edema of all eyes (8/8 eyes, 100%) in the ODE group was completely mitigated after orbital decompression. The CRF resolution of 2 eyes (2/8 eyes, 25%) in the ODE group and no eyes in the NODE group was mitigated.

Conclusions

Balanced orbital decompression can significantly improve visual functions and eliminate optic disc edema in DON patients, whether CRF relieves or not.

Decreased macular choriocapillaris in thyroid-associated ophthalmopathy: focusing on chorioretinal folds with and without optic disc edema

Purpose

The aim of this study was to evaluate the vessel density (VD) of the macular choriocapillaris (CC) and retina in thyroid-associated ophthalmopathy (TAO) patients with chorioretinal folds (CRFs) with and without optic disc edema (ODE) and the correlations of these characteristics with visual function.

Method

This was a cross-sectional study. Twenty TAO patients with CRFs (35 eyes) and 20 normal subjects (normal group, 40 eyes) were recruited at the Ophthalmology Department of the Sun Yat-sen Memorial Hospital from March 2018 to October 2022. Then, CRF patients were divided into two groups, the ODE and non-ODE groups (NODE), based on the presence or absence of ODE. All the patients underwent optical coherence tomography angiography (OCTA) and the VD of the macular CC and retina was computed. The correlation of VD and visual function was analyzed.

Results

Compared with the normal group, the macular whole-image VD in the retinal superficial layer (SLR-mwiVD: 49.82 ± 3.38 in the normal group, 42.44 ± 5.40 in the NODE group, and 42.51 ± 5.37 in the ODE group), deep layer (DLR-mwiVD: 51.05 ± 6.23 in the normal group, 45.71 ± 6.66 in the NODE group, and 46.31 ± 5.48 in the ODE group), and CC (CC-mwiVD: 70.23 ± 2.47 in the normal group, 68.04 ± 3.73 in the NODE group, and 63.09 ± 6.51 in the ODE group) was decreased in the NODE (all p < 0.05) and ODE group (all p < 0.01). There was no difference in these parameters except CC-mwiVD between the ODE and NODE groups. The CC-mwiVD in the ODE group (63.09 ± 6.51) was significantly reduced compared with that in the NODE group (68.04 ± 3.73, p = 0.004). All these VD parameters were negatively correlated with BCVA, VF-PSD, and P100 latency and positively associated with VF-MD, P100 amplitude, and HRR scores (all p < 0.05).

Conclusions

There was a significant decrease in the VD of the macular CC and retina of patients with CRFs with or without ODE, which was correlated with visual dysfunction. The VD of the macular CC in CRF patients with ODE was significantly reduced compared with that in the NODE group, but similar results were not observed in the retina.

Macular and peripapillary optical coherence tomography angiography metrics in thyroid-associated ophthalmopathy with chorioretinal folds

PURPOSE

To evaluate macular and radial peripapillary capillary (RPC) microvascular densities and the thickness of the retinal nerve fiber layer (RNFL) in thyroid-associated ophthalmopathy (TAO) with chorioretinal folds (CRFs) and the associations of these characteristics with visual function.

METHOD

A cross-sectional study was performed at the Ophthalmology Department of the Sun Yat-sen Memorial Hospital from March 2018 to August 2021. All patients underwent ocular examination, ophthalmic function tests and optical coherence tomography angiography (OCTA). The microvascular densities in the macula and optic papilla in the TAO with CRFs or without CRFs. Correlation analyses were used to examine the association of microvascular density and visual function.

RESULTS

Ten TAO patients with CRFs (CRF group, 20 eyes) and 10 TAO patients without CRFs (NCRF group, 20 eyes) were recruited for the study. Visual function measurements, including best-corrected visual acuity (BCVA), were found to be worse in the CRF group (all p < 0.05). The macular whole-image vessel density in the superficial layer (SLR-mwiVD) was significantly decreased in the CRF group (p < 0.05). The RPC whole-image vessel density (RPC-wiVD) was significantly decreased in the CRF group (p < 0.05), particularly in the temporal subfields. The P100 amplitude of visual evoked potentials (VEPs) was positively associated with SLR-mwiVD and RPC-wiVD. The thickness of RNFL in the CRF group was obviously thicker than that in the NCRF group (p < 0.05).

CONCLUSIONS

Our study showed decreased microvascular density of the macula and RPC and thicker RNFL in TAO patients with CRFs. CRFs with decreased microvascular density should be regard as an indicator of visually threatening conditions.

Selective deficits of S-cone in thyroid-associated ophthalmopathy patients without clinical signs of dysthyroid optic neuropathy

Purpose

We explored whether thyroid-associated ophthalmopathy (TAO) patients without clinical signs of dysthyroid optic neuropathy (DON) would have a selective deficit mediated by S-cone.

Methods

Thirty-two TAO patients without clinical signs of DON (non-DON, 42.03 ± 9.59 years old) and 27 healthy controls (41.46 ± 6.72 years old) participated in this prospective, cross-sectional study. All observers were tested psychophysically after passing color screening tests and a comprehensive ocular examination. Isolated L-, M-, and S-cone contrast thresholds were measured at 0.5 cyc/deg using Gabor patches. We calculated the area under the receiver operating characteristic (ROC) curve to quantify the ability of chromatic contrast sensitivity to detect the early visual function changes in non-DON patients.

Results

S-cone contrast sensitivity in non-DON patients was found to be lower than that of healthy controls (P < 0.001), whereas the sensitivities to L- and M-cone Gabor patches were similar between these two groups (P = 0.297, 0.666, respectively). Our analysis of the ROC curve revealed that the sensitivity to S-cone had the highest index to discriminate non-DON patients from healthy controls (AUC = 0.846, P < 0.001). The deficit of S-cone was significantly correlated with muscle index in non-DON patients (R = 0.576, P = 0.001).

Conclusion

There is a selective S-cone deficit in the early stage of TAO. S-cone contrast sensitivity could serve as a sensitive measure of visual impairments associated with early DON in patients with TAO.

Analysis of retinal vasculature changes in indirect traumatic optic neuropathy using optic coherence tomography angiography

AIM

To assess the retinal vasculature alterations in indirect traumatic optic neuropathy (ITON) patients following craniofacial trauma by optic coherence tomography angiography (OCTA).

METHODS

Patients diagnosed of monocular ITON were recruited from August 2016 to May 2020. OCTA was performed using the AngioVue OCT-A system for two cube scans centered at the optic nerve head and fovea. OCTA data included thicknesses of peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC), as well as proportion of capillary perfusion and data were analyzed for correlation with post-injury timepoints: within 7, 8-30, 31-90, and 91-365d.

RESULTS

A total of 73 ITON patients were studied. Significant thinning of RNFL and GCC layers and attenuation of microvascular perfusion were observed in ITON eyes as compared to contralateral unaffected eyes (for most of the analyzed sectors and quadrants, P<0.05). Without respect to surgical intervention and vision recovery, the decrease in retinal layer thicknesses and microvascular perfusion was time-dependent, and most significant within three months (P<0.001).

CONCLUSION

ITON presents with time-dependent thinning of retinal layers and attenuation of microvasculature, indicating possible degeneration of retinal ganglion cells due to reduced retinal blood supply.

Peripapillary structural and microvascular alterations in early dysthyroid optic neuropathy

Background

To explore the changes in blood supply and structure around the optic nerve head (ONH) in thyroid-associated ophthalmopathy (TAO) patients with suspected dysthyroid optic neuropathy (DON).

Methods

TAO patients [19 with DON; 24 non-DON (NDON); 20 with equivocal DON (EDON)], and 34 control subjects were examined. Optical coherence tomography angiography (OCTA) was used to obtain peripapillary retinal nerve fiber layer (p-RNFL) and vessel density parameters, including the ONH whole image vessel density (ONH-wiVD) and the radial peripapillary capillary vessel density (RPC-VD) in early DON.

Results

Although there were no differences in p-RNFL thickness among the groups, there were differences in the ONH-wiVD of each grid section and the RPC-VD in all areas (P < 0.01). Compared with healthy controls, the EDON eyes had significantly lower RPC-VDs in all aeras (P < 0.05).The peripapillary region was further divided into eight sectors, and the RPC-VD in the temporal upper, superior temporal, and temporal lower sectors in the EDON group were significantly lower than in the controls. The visual impairment was closely related to the loss of peripapillary capillary vessel density. Univariate correlation analysis showed that the ONH-wiVD and RPC-VD of the TAO groups were negatively correlated with the intraocular pressure (r = − 0.296, P = 0.006; r = − 0.258, P = 0.016 respectively).

Conclusions

EDON patients had significantly lower ONH-wiVD and RPC-VD than control subjects, and the temporal and upper VDs were more likely to be affected in the early stage of TAO. The combined use of spectral domain optical coherence tomography and OCTA technologies offer a new method for early diagnosis of suspected DON patients.

Reduced choroidal peripapillary capillaries in thyroid-associated ophthalmopathy with early stage of dysthyroid optic neuropathy

AIM

To investigate whether the subtle change of choroidal/retinal vessel densities and volumes in thyroid-associated ophthalmopathy (TAO) could be an early sign to detect dysthyroid optic neuropathy (DON).

METHODS

This was a retrospective cross-sectional study, and a total of 98 eyes from 50 subjects were enrolled under certain criteria. Thirty-four eyes of normal controls and 64 eyes of TAO, including 39 eyes of DON and 25 eyes of TAO without DON, underwent optical coherence tomography angiography (OCTA) scanning. All the tested parameters of OCTA scanning including choroid radial peripapillary capillaries (RPC), retinal nerve fiber layer (RNFL), and macular ganglion cell complex (GCC) were compared among groups, and the correlation between OCTA parameters and visual function parameters was also investigated.

RESULTS

Whole choroidal RPC was significantly reduced in DON (48.24%±0.4978%) compared to normal (50.33%±0.3173%) and TAO without DON (49.16%±0.5463%; P=0.0041). The reduction of whole choroidal RPC was also correlated with visual field (VF) defect in DON (r=0.5422, n=39). Although vision acuity and VF were improved in all the patients with DON after being treated with medical and surgical decompression, the reduction of RPC density were not reversed.

CONCLUSION

There is a notable reduction in choroidal RPC in DON, which is correlated with VF defect. The reduction of RPC density could not be reversed immediately by medical and surgical decompression even when vision and VF were improved. These findings suggest that choroidal RPC could be a useful parameter to diagnose and monitor early stage of DON.

Optic Nerve Head Vessel Density Changes from Graves' Disease without TED to TED Dysthyroid Optic Neuropathy: Does Optic Nerve Head Ischemia Play a Role?

PURPOSE

To compare the retinal peripapillary capillary (RPC) vessel density (VD) between 5 groups of patients on the spectrum of thyroid eye disease (TED).

METHOD

This is a prospective comparative study looking at 5 groups of patients who were consecutively included from January 2018 to March 2021. They were composed of: Healthy volunteers (39 eyes and 20 subjects), patients with Graves' disease without TED (26 eyes and 13 patients), mild TED (28 eyes and 14 patients), moderate-severe TED (30 eyes and 17 patients), and TED with dysthyroid optic neuropathy (DON) (21 eyes and 12 patients). Ocular and periocular examination, visual field indices, RPC-VD (with optical coherence tomography angiography), and retinal nerve fiber layer, and macular ganglion cell complex thickness were recorded.

RESULT

An initial insignificant (0.5 < p < 0.9) rise in the peripapillary-VD (pp-VD) and whole image-VD (wi-VD) from the healthy subject to the Graves' disease without TED was followed by a significant (p = 0.001) fall in RPC-VD in different severity grades of the TED. Paired comparison between the 5 groups showed that the statistically significant fall from the Graves' disease group occurred in the moderate-severe and DON groups (0.001 ≤ p ≤ 0.04). No variable significantly affected the VD (0.08 ≤ p ≤ 0.9). A lower wi-VD and pp-VD were significantly (0.001 ≤ p ≤ 0.009) correlated with the impaired optic nerve functional and structural tests. The sensitivity and specificity of wi-VD (81% and 76%) and pp-VD (69% and 71%) for detecting the DON were statistically significant (p < 0.001).

CONCLUSION

Despite an insignificant rise in the wi- and pp-VD from the healthy volunteers to the patients with Graves' disease without TED, VD showed a declining trend in the course of patients with TED, which was statistically significant in the moderate-severe TED and DON groups.

Evaluating the interreader agreement and intrareader reproducibility of Visual Field Defects in Thyroid Eye Disease- Compressive Optic Neuropathy

PURPOSE

To categorize visual field (VF) defects according to Freitag and Tanking's (FT) classification in Thyroid Eye Disease-Compressive Optic Neuropathy (TED-CON) and evaluate the interreader agreement and intrareader reproducibility of the classification.

SUBJECTS AND METHODS

In this retrospective, observational study we included medical reports of 96 eyes (51 patients), who underwent VF testing with TED-CON in Ludwig-Maximilians-University (2008-2019). Two readers separately examined the VFs at the time of the TED-CON diagnosis, each offering two readings of the same VF in a time interval of 1 month. None of our patients were diagnosed with only VF testing. The visual field testing was only performed when the inclusion criteria for TED-CON were met.

RESULTS

The most common VF defects upon TED-CON diagnosis were stage 1b defects in FT classification (34.4% for reader 1, 35.4% for reader 2), followed by stage 2b (10.4% for reader 1, 14.6% for reader 2), and stage 3 (10.4% for both readers). The overall interreader agreement between 2 examiners was substantial for the first reading (69.8% agreement, kappa 0.635 (95% CI [0.525-0.745])) and moderate for the second reading (66.7% agreement, kappa 0.598 (95% CI [0.488-0.708])). The intrareader reproducibility ranged from substantial to almost perfect (78.1% agreement) between readings (kappa 0.736 (95%CI [0.638-0.834])) for reader 1 and 90.6% agreement (kappa 0.885 (95%CI [0.814-0.956])) for reader 2.

CONCLUSION

We found good BCVA (LogMAR ≤ 0.2), in nearly half of the cases (44 eyes, 45.8%) and also, strikingly near perfect visual acuity (BCVA LogMAR ≤0.1) in 22.9% of the cases (22 eyes) with TED-CON. We conclude that clinicians should be alert to VF defects in the inferior region (stage 1a/1b in the FT classification) even in patients with a good BCVA.

A Pilot Study of Subclinical Non-Capillary Peripapillary Perfusion Changes in Thyroid-Related Orbitopathy Detected Using Optical Coherence Tomography Angiography

Purpose

Hemodynamic changes surrounding the optic nerve head are known to occur in thyroid-related orbitopathy (TRO). This pilot study explores the capillary and non-capillary peripapillary perfusion changes of the retina in TRO eyes without dysthyroid optic neuropathy (DON) using optical coherence tomography angiography (OCT-A).

Methods

Non-capillary and capillary peripapillary perfusion densities were calculated using single 4.5 × 4.5mm en face “RPC layer” OCT-A scans of 8 TRO patients without DON (8 eyes, mean age 40.6 years, range 23–69 years). Results were compared to a previously published dataset of 133 healthy controls (133 eyes, mean 41.5 years, range 11–83 years). The strength of association was measured between OCT-A perfusion densities and clinical measures of TRO.

Results

Non-capillary peripapillary perfusion density in TRO eyes was found to be significantly decreased compared to healthy controls (TRO group 15.4 ± 2.9% vs controls 21.5 ± 3.1%; p < 0.0001). Capillary peripapillary perfusion densities showed no significant difference (TRO group 42.5 ± 1.8% vs controls 42.5 ± 1.5%; p = 1.0). Clinical measures of disease did not correlate well with OCT-A perfusion densities (p>0.05).

Conclusion

These findings may represent decreased blood flow and subclinical ischemia to the optic nerve. We discuss possible pathogenic mechanisms of thyroid-related vasculopathy, including vessel wall thickening due to immunologically-induced media enlargement.

The Changes in Optic Nerve after Orbital Decompression Surgery for Thyroid Eye Disease and Case Reports of Ischemic Optic Neuropathy

Purpose

To demonstrate the changes in the retinal nerve fiber layer (RNFL) after orbital decompression for thyroid eye disease (TED).

Methods

We retrospectively enrolled 52 surgical TED patients, 30 nonsurgical TED patients, and 30 control subjects. Five surgical TED eyes with disc edema were excluded. The surgical TED patients were classified into the “dysthyroid optic neuropathy (DON)” group (16 eyes) and the “non-DON” group (83 eyes). Optical coherence tomography (OCT) and visual field (VF) examinations were performed preoperatively and 6 months later. The control subjects and nonsurgical TED patients received two OCT examinations at 6-month intervals. The postoperative changes in the RNFL thickness were compared between groups. Three cases with severe postoperative vision loss were presented additionally.

Results

The changes in the RNFL thickness of the controls (0.5 ± 3.4 μm) and the nonsurgical TED patients (0.3 ± 2.8 μm) were significantly smaller than the surgical TED patients (P < 0.001). The DON group (−9.2 ± 9.2 μm) had greater RNFL thickness reduction than the non-DON group (−3.9 ± 5.4 μm) (P = 0.002). Bone removal decompression was associated with decreased RNFL in the non-DON (P = 0.025; β = −2.49) and DON (P = 0.042; β = −9.43) groups. Three cases who were hard to operate due to extensive fibrosis experienced severe vision loss postoperatively due to anterior ischemic optic neuropathy, posterior ischemic optic neuropathy, and posterior ciliary artery occlusion, respectively.

Conclusions

TED patients experienced subclinical optic nerve injury and significant RNFL loss after the orbital decompression surgery. Aggressive manipulation during decompression surgery may lead to dreadful vision loss. Tailored surgical plans and delicate manipulation are warranted.

Alterations in Spontaneous Neuronal Activity and Microvascular Density of the Optic Nerve Head in Active Thyroid-Associated Ophthalmopathy

PURPOSE

To investigate changes in local spontaneous brain activity in patients with active thyroid-associated ophthalmopathy (TAO) and explore the relationship between such alterations and microvascular indices.

METHODS

Thirty-six active TAO patients with active phase and 39 healthy controls (HCs) were enrolled in this study. All participants underwent resting-state functional magnetic resonance imaging (rs-fMRI), neuropsychological tests, and ophthalmological examinations. The rs-fMRI-based fractional low-frequency fluctuation amplitude (fALFF) analysis methods were used to assess spontaneous brain activity in both groups. The structure (peripapillary retinal nerve fiber layer, pRNFL) and microvascular indices (the optic nerve head (ONH) whole image vessel density, ONH-wiVD, and peripapillary vessel density) were analyzed through optical coherence tomographic angiography imaging. The relationship between abnormal spontaneous brain activity and ophthalmological indices was analyzed using the Spearman's rank correlation analysis.

RESULTS

Compared with HCs, active TAO patients had increased fALFF in the right inferior temporal gyrus (R.ITG) and left posterior cingulate gyrus (L.PCC), but decreased fALFF in the right calcarine (R.CAL). The fALFF values in L.PCC were positively correlated with peripapillary vessel density, whereas fALFF values in R.CAL were negatively related to peripapillary vessel density.

CONCLUSIONS

This study demonstrates that changes in spontaneous brain activity of active TAO are accompanied by peripapillary microvascular variations. These results provide insights into the pathophysiological mechanisms of active TAO. In addition, the combination of fALFF values and peripapillary vessel density may be served as important references for better clinical decision making.

Elevated pulse pressure correlated with reduced retinal peripapillary capillary in thyroid-associated ophthalmology with visual field defect

PURPOSE

To quantify the retinal vessel density in thyroid-associated ophthalmology (TAO) patients with visual field (VF) defect and examine its associations with mechanical and system vascular risk factors for underlying pathogenesis of VF defect in TAO.

METHODS

The cohort was composed of 62 TAO eyes (39 with VF defect and 23 without VF defect). The pulse pressure (PP), intraocular pressure (IOP), ophthalmic rectus muscular index (MI), superficial retinal capillary plexus (SRCP), radial peripapillary capillary (RPC) density, and other related parameters were measured. The associations among these factors and VF mean deviation (MD) were analyzed.

RESULTS

In TAO patients with VF defect, reduced RPC density, higher PP, and larger horizontal and vertical MI were found (all P < 0.03) when compared to TAO patients without VF defect. The RPC density was correlated with VF MD value (r = 0.242, P = 0.029), while SRCP density was not (P = 0.419). In univariable general estimating equation (GEE) analysis with RPC density as the outcome, PP and its fluctuation showed a significant association (both P < 0.04). In the final RPC model with multivariable GEE analysis, only PP (β = -0.082, P = 0.029) showed significance while PP fluctuation (P = 0.080) did not.

CONCLUSIONS

The elevated PP was correlated with reduced retinal peripapillary perfusion in TAO resulting in VF defect. These data suggested that the system vascular factor may be important in the pathogenesis of reduced retinal perfusion resulting in visual impairment in TAO.

The changes of retinal nerve fibre layer and ganglion cell layer with different severity of thyroid eye disease

OBJECTIVES

To evaluate the changes of retinal nerve fibre layer (RNFL) and ganglion cell layer/inner plexiform layer (GCL/IPL) with the severity of thyroid eye disease (TED).

METHODS

One hundred and forty-five eyes of 75 patients with TED and 70 eyes of 35 healthy controls were included. The eyes with TED were divided into mild group (35 eyes), moderate-to-severe group (42 eyes) and DON group (68 eyes). The thickness of RNFL and GCL/IPL were measured by optic coherence tomography (OCT). Clinical activity score (CAS), best corrected visual acuity (BCVA), intraocular pressure (IOP), proptosis and mean deviation (MD) by Humphrey perimetry were assessed.

RESULTS

The CAS had significant difference between the three groups (p < 0.001). The proptosis and IOP were significantly higher in DON group and moderate-to-severe group than mild group (p < 0.05). The MD and BCVA were significantly worse in DON group compared with mild group and moderate-to-severe group (p < 0.001). The mean GCL/IPL thickness was thinnest in DON group (p < 0.001). The mean RNFL thickness had significant difference between moderate-to-severe group and DON group (p = 0.036). The mean GCL/IPL thickness had a significant correlation with MD (r = 0.449, p < 0.001) and VA (r = -0.388, p < 0.001), whereas the mean RNFL thickness had no significant correlation with MD (p = 0.082) or VA (p = 0.226).

CONCLUSIONS

Subclinical optic neuropathy might progress in the patients with moderate-to-severe TED. OCT measurements of GCL/IPL and RNFL are useful to detect the early changes of optic nerve. The thinning of GCL/IPL might be a strong suggestion for closer vision follow-up and earlier decompression surgery.

Altered peripapillary vessel density and nerve fiber layer thickness in thyroid-associated ophthalmopathy using optical coherence tomography angiography

Objective

To measure the peripapillary vessel density (VD) and retinal nerve fiber layer thickness (RNFLT) in thyroid-associated ophthalmopathy (TAO) and dysthyroid optic neuropathy (DON) patients using optical coherence tomography angiography (OCTA), and determine their prognostic relevance.

Methods

Forty-three TAO patients with or without DON (82 eyes in total) and 26 healthy subjects (52 eyes) were enrolled. All participants underwent ophthalmology and endocrinology tests. The peripapillary VD in retinal peripapillary capillary layer and RNFLT were analyzed using OCTA images. Multiple linear regression analysis was used to assess the relationship between peripapillary VD /RNFLT and the relevant factors.

Results

The total peripapillary VD and RNFLT were significantly lower in the DON patients compared to the other groups (P < 0.001, 95% confidence intervals), and each quadrant of VD and RNFLT showed similar results except temporal RNFLT. No significant difference was seen between the RNFLT and VD of active non-DON (ANDON), inactive non-DON (NDON) patients and normal control (NC) group. Multivariable linear regression model showed that high IOP is an independent risk factor for lower peripapillary VD and RNFLT (β = −0.465, P < 0.001 and β = −0.343, P = 0.002 respectively).

Conclusion

OCTA parameters are suitable indicators for diagnosing DON. TAO patients with high IOP should be considered at high risk of retinal vessel and nerve fiber layer deterioration. In addition, patients with TAO should be advised to quit smoking since it could affect peripapillary VD and RNFLT.

Effect of smoking on retinal thickness and vascular density in thyroid eye disease

Purpose

To evaluate the effect of smoking on retinal thickness and macular and peripapillary vascular density in thyroid eye disease (TED).

Methods

In this cross-sectional study, subjects diagnosed with TED were analyzed in three groups: smokers, passive smokers, and non-smokers. Ganglion cell complex thickness, total retinal thickness, macular superficial vascular plexus densities, deep vascular plexus densities, optic nerve head, and radial peripapillary capillary density were measured in each group.

Results

Twenty-two eyes (21.6%) of active smokers, 11 eyes (10.8%) of passive smokers, and 69 eyes (67.6%) of non-smokers constitute the study subjects. Twenty-one eyes (12.6%) had active status (clinical activity score ≥3), 77 eyes (46.1%) were neither active nor compressive, four eyes (2.4%) of two patients constituted the compressive group. Age and disease activity adjusted analysis was performed. Ganglion cell complex thickness of smokers was significantly higher than non-smokers in the inferior hemi-parafoveal sector (p = 0.04). Active smokers had significantly higher (p < 0.01) retinal thickness in all sectors compared to non-smokers, except the foveal sector. Smokers had lower superficial vessel density in the superior parafoveal sector compared to non-smokers (p = 0.04). Considering deep vessel densities between smokers and non-smokers, no significant difference was observed. Radial peripapillary capillary densities (significant difference was observed in the whole image and infranasal peripapillary sector), Macular vascular densities (significant difference was observed in parafoveal sectors), and optic nerve head (not reaching statistical significance level in any sectors) were highest in passive smokers.

Conclusions

Smoking is associated with increased total retinal thickness. Macular vascular densities were not different between smokers and non-smokers in TED.

Smoking effect on peripapillary and macular microvascular structure in inactive Graves' ophthalmopathy

OBJECTIVE

The aim of this study was to evaluate the smoking effect on peripapillary and macular microvascular structure in patients with inactive Graves' ophthalmopathy (GO) and to compare these structures with those of healthy control subjects.

METHODS

A total of 34 healthy participants (control group), 22 inactive GO patients with smoking (smoker group) and 19 inactive GO patients with non-smoking (non-smoker group) were recruited in this prospective study. After detailed ophthalmological examination, vessel densities (VD) of the superficial capillary plexus (SCP), deep capillary plexus (DCP), retinal peripapillary capillary (RPC) and foveal avascular zone (FAZ) area, and acircularity index (AI) of the FAZ were analysed with optical coherence tomography angiography (OCTA) for each eye.

RESULTS

Vessel density in the total peripapillary; superior and inferior sectors of RPC were significantly lower in inactive GO patients with smoking (p < 0.05 for all sectors) compared to control group. Besides, the FAZ AI was significantly higher in smoker and non-smoker inactive GO groups compared to healthy subjects (p = 0.0001, p = 0.0001, respectively). No significant difference was found in the FAZ area, and all SCP, DCP macular measurements between groups (p > 0.05 for all).

CONCLUSION

OCTA findings of lower peripapillary VD in the smoker group show smoking effect on the optic disc head microvasculature in inactive GO patients. These results could reflect early subclinical optic disc vasculature damage in smoker inactive GO subjects.

The retinal vasculature pathophysiological changes in vision recovery after treatment for indirect traumatic optic neuropathy patients

Purpose

To evaluate the retinal vasculature pathophysiological changes of indirect traumatic optic neuropathy (ITON) patients after effective surgery.

Methods

Monocular ITON patients who underwent endoscopic trans-ethmosphenoid optic canal decompression (ETOCD) or conservative treatments in Zhongshan Ophthalmic Center from January 2017 to June 2020 were recruited. Visual acuity (VA), visual evoked potential (VEP), oxygen saturation of retinal blood vessels (SO₂), and optical coherence tomography angiography (OCT-A) were measured. All patients were followed up at least 3 months after treatments.

Results

A total of 95 ITON patients were recruited, including 77 patients who underwent ETOCD and 18 patients who underwent conservative treatments. After treatments, more patients received ETOCD (59/77 = 76.6%) presented with improved VA compared with the patients with conservative treatments (6/18 = 33.3%). Compared with the pre-therapeutic measurements, VEP were significantly improved after surgery in ETOCD-treated patients (P < 0.05). Latent periods of P1 and N2, as well as amplitude of P2 of VEP parameters, showed more sensitive to vision recovery (P < 0.05). Retinal artery SO₂ and the differences between arteries and veins were improved in ETOCD-treated patients (P < 0.05). Meanwhile, with OCT-A examination, the retinal thickness and retinal vessel density were notably better in ETOCD-treated patients after surgery than that in patients received conservative treatments (P < 0.05).

Conclusions

Vision recovery after effective treatment of ITON patients was associated with the increased oxygen saturation of retinal vessels, better availability of oxygen in the retina, greater vessel density, and thicker retinas, which might further underlie the vasculature mechanism of vision recovery in ITON patients.

Retinal vascularity, nerve fiber, and ganglion cell layer thickness in thyroid eye disease on optical coherence tomography angiography

Purpose: To compare the retinal vascularity, peripapillary vascularity, nerve fiber layer thickness and ganglion cell layer thickness between active, inactive thyroid eye disease (TED) and healthy eyes.Methods: Retrospective comparative cross-sectional cohort study. Patients with TED, active and inactive on the VISA score, and healthy eyes were included. All patients underwent optical coherence tomography angiography with detailed demographic and clinical data capture. Using automated software, retinal and peripapillary vascularity index, nerve fiber layer thickness, and ganglion cell layer thickness were calculated and were compared between the groups.Results: Twenty-four eyes with active TED, 102 eyes with inactive TED and 52 healthy eyes were included. Independent sample t test was used to compare parametric data and Mann-Whitney test to compare non-parametric data. The age and gender were comparable across groups. The peripapillary vascularity index (26.82 ± 4.13 versus 34.92 ± 5.08, p = .002) and the macular vascularity index (20.32 ± 2.5 versus 31.21 ± 3.89, p < .0001) were reduced in active TED eyes versus inactive eyes. Macular vascularity index was comparable in the inactive versus the healthy eyes. The RNFL thickness was increased in the active TED eyes versus the inactive eyes (45.11 ± 18.3 versus 35.55 ± 7, p = .03) and active versus healthy eyes (45.11 ± 18.3 versus 36.28 ± 7.89, p = .03). Ganglion cell layer thickness between all three groups was comparable.Conclusion: Decrease in peripapillary and macular vascular density and increase in RNFL thickness are seen in active TED compared to inactive TED and healthy eyes. In disease inactivity, these parameters are comparable to healthy eyes.

Optical coherence tomography angiography in neuro-ophthalmology: Current clinical role and future perspectives

Optical coherence tomography angiography (OCTA) is a noninvasive, depth-resolved imaging tool for the appraisement of retinal vascular changes. Since its introduction, the understanding of diabetic retinopathy, age-related macular degeneration, central serous retinopathy, and other diseases has been enriched on many fronts. Its dyeless imaging property maps retinal as well as deeper choroidal vasculature in quick succession with good reproducibility. Hence, it can play an important role in the diagnosis and management of optic nerve-related diseases as well. A detailed literature review for its role in nonarteritic anterior ischemic optic neuropathy, papilledema, optic disc drusen, papillitis, hereditary optic neuropathies, central nervous system diseases, and others highlights its role. The whole spectrum of neuro-ophthalmological diseases shows consistent peripapillary and macular capillary changes with structural and functional correlation. The superficial and deeper retinal and choroidal vasculatures are affected depending on the nature of the disease process. Hence, OCTA positions itself as a useful, noninvasive tool in the armamentarium of a neuro-ophthalmologist in future; however, there are several limitations of the OCTA with respect to its technical abilities in challenging neuro-ophthalmic cases. Therefore, future research should be directed to enhance the technical capabilities of OCTA and to determine the more precise role of it in the prognosis of neuro-ophthalmic diseases.

Determination of peripapillary vessel density in optic disc drusen using EDI-OCT and OCT angiography

Optical coherence tomography angiography (OCTA) is a rapidly developing technique which generates angiographic images non-invasively. This study proposes a method to determine the vessel density in OCTA scans in general and especially the local peripapillary vessel density. The method produces vessel density heatmaps that contain information about the local vessel density. We apply the method in a small study to demonstrate its applicability and its potential to investigate the influence of local conditions on the vessel density. In the study, we combine information from enhanced depth imaging optical coherence tomography (EDI-OCT) about the location of optic disc drusen (ODD) with information from OCTA about the vessel density. We see a reduction in local peripapillary vessel density in peripapillary sections with a large volume of ODD.