Choroidal Medium-Large Vascular Index Identified as Optimal OCT-A Biomarker for Thyroid Eye Disease Activity
Key Insights
A retrospective study of 97 TED patients and 26 healthy controls identifies subfoveal choroidal medium-large vascular index (search) (CMLVI) as a superior biomarker for distinguishing active from inactive disease.
CMLVI at the fovea demonstrated an AUC of 0.811 in ROC analysis, outperforming retinal thickness, retinal vascular indices, and choroidal capillary vascular index.
Active TED patients showed significantly greater subfoveal and parafoveal choroidal thickness and higher CMLVI compared to inactive patients and controls (P < 0.001).
A newly published study in Eye has identified the choroidal medium-large vascular index (search) (CMLVI) as an optimal, objective optical coherence tomography angiography (OCT-A) biomarker for assessing disease activity in thyroid eye disease (search) (TED). The finding addresses a critical gap in current clinical practice, where the widely used clinical activity score is considered subjective and lacks adequate sensitivity, potentially leading to suboptimal patient outcomes.
The retrospective cross-sectional study enrolled 30 active TED patients (50 eyes), 26 inactive TED patients (47 eyes), and 26 healthy controls (50 eyes). All participants underwent macular OCT and OCT-A to quantify retinal thickness, choroidal thickness, retinal superficial and deep vascular indices, choroidal capillary vascular index, and CMLVI.
Choroidal Changes Predominate Over Retinal Alterations
The results demonstrated that subfoveal and parafoveal choroidal thickness was significantly greater in the active TED group compared to both the inactive group and healthy controls (P < 0.05). Among the vascular indices assessed, CMLVI in both the subfoveal and parafoveal zones was significantly higher in active TED patients than in those with inactive disease or controls (P < 0.001).
Notably, no significant differences were observed for retinal thickness, retinal vascular indices, or the choroidal capillary vascular index between active and inactive groups. This pattern indicates that active TED manifests more prominently through choroidal vascular changes than through retinal alterations.
Diagnostic Performance and Clinical Implications
Receiver operating characteristic (ROC) curve analysis revealed that CMLVI at the fovea exhibited superior diagnostic efficacy for distinguishing active from inactive TED, with an area under the curve (AUC) of 0.811. The researchers noted, "The superior performance of CMLVI may stem from its ability to directly reflect the underlying vascular perturbations of active TED, which are more prominently manifested in the choroidal circulation than in retinal changes."
The study authors concluded that subfoveal CMLVI represents the "optimal, objective OCT-A biomarker for assessing TED activity." They added that this "finding holds significant implications for improving the precision of TED activity grading in clinical settings and may contribute to the development of more sensitive and individualized treatment strategies, ultimately optimizing patient management outcomes."
The retina and choroid serve as crucial observation windows for monitoring ocular diseases, and these findings reinforce the value of OCT-A in providing quantifiable, objective metrics that may complement or refine existing clinical assessment tools for TED.