Choroidal vascularity index in thyroid-associated ophthalmopathy: a cross-sectional study

Pasquale Loiudice,Marco Pellegrini,Michele Marinò,Giamberto Casini,Barbara Mazzi,Ilaria Ionni,Marco Nardi,Michele Figus,Giuseppe Covello

doi:10.1186/s40662-021-00242-6

Pasquale Loiudice, Marco Pellegrini + Show 7 more

Open Access

https://doi.org/10.1186/s40662-021-00242-6

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Abstract

BackgroundHemodynamic changes have been observed in patients with Graves’ disease. The aim of our study was to evaluate choroidal vascular change using the choroidal vascularity index (CVI) in patients with thyroid-associated ophthalmopathy (TAO).MethodsIn this cross-sectional observational study, 40 patients affected by TAO were recruited. Forty healthy individuals, matched for age and sex, served as controls. Foveal enhanced-depth imaging optical coherence tomography scans were obtained from all participants. Images were binarized using the ImageJ software and luminal area (LA) and total choroidal area (TCA) were measured. CVI was calculated as the proportion of LA to TCA. The relation between CVI or subfoveal choroidal thickness (SFCT) and clinical activity score, exophthalmometric value, diplopia status, gender, and age was evaluated.ResultsCVI was significantly higher in patients with TAO (P = 0.004). No significant difference was observed in SFCT (P = 0.200) and TCA (P = 0.153) comparing TAO patients and healthy controls. LA was significantly higher in TAO group (P = 0.045). On multiple regression analysis, CVI was associated with TCA (P = 0.043). No association was found between SFCT or CVI and TCA, clinical activity score, exophthalmometric value, Inami value, diplopia status, gender or age (P > 0.05).ConclusionsThis is the first study that has demonstrated an increase in CVI in eyes with TAO compared with healthy controls and has assessed its association with clinical features.

Highlights

Hemodynamic changes have been observed in patients with Graves’ disease
Forty cases were diagnosed with thyroidassociated ophthalmopathy (TAO) and 40 subjects served as controls
Since there was a strong correlation between right and left eye variables, only data of the right eyes were included in the statistical analysis

Summary

Introduction

Hemodynamic changes have been observed in patients with Graves’ disease. Thyroid-associated ophthalmopathy (TAO), called Graves’ ophthalmopathy or Graves’ orbitopathy, is an autoimmune disorder involving the orbital tissue, commonly found in patients with Graves’ disease [1]. Several risk factors have been investigated, including tobacco smoking and number of cigarettes smoked per day, older age at diagnosis of Graves’ hyperthyroidism, longer (2021) 8:18 duration of the disease, uncontrolled thyroid dysfunction and prior radioactive iodine treatment [4,5,6,7]. Once activated by thyroid-stimulating immunoglobulins, fibroblasts proliferate and produce proinflammatory cytokines and extracellular matrix constituents [9]; this results in hygroscopic swelling of extraocular muscles and expansion of the adipose tissue. Three pathophysiological steps have been identified in the socalled “Cone model”: (a) expansion of rectus muscles and fat, forward displacement of extra-conal fat; (b) axial advancement of the globe and rectus muscle stretching; (c) impaired posterior venous drainage and reversal of conjunctival venous flow with eyelid edema [10]

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