Changes in choroidal thickness and choroidal vascularity index in thyroid eye disease: a systematic review

Purpose To evaluate the evidence for changes in choroidal thickness and choroidal vascularity index (CVI) in people with thyroid eye disease (TED), stratified by severity, as measured by optical coherence tomography (OCT).Methods Systematic review, including quality assessment, of published studies investigating choroidal thickness in TED. Outcomes of interest included CVI, subfoveal choroidal thickness, mean choroidal thickness, and peripheral choroidal thickness in four quadrants (superior, inferior, medial, lateral).Results Nineteen studies were included which contained measurements from 1067 eyes in 798 patients with TED. Most studies found an increased CVI and increased choroidal thickness in patients with TED compared to normal controls, especially in the subfoveal region. In addition, several studies reported an increased thickness in patients with active vs. inactive TED, although the results are equivocal. Finally, many studies reported associations between increased choroidal thickness and worsened clinical measurements of disease activity, such as Clinical Activity Score (CAS).Conclusions This systematic review provided evidence for an association between increased CVI/choroidal thickness and TED, suggesting a potential for OCT-measured CVI/choroidal thickness as an objective clinical marker. Given heterogeneity, future studies are needed to assess the role of measuring the choroidal changes in diagnosis and management of TED.