Evaluation of retinal and choroidal variations in thyroid-associated ophthalmopathy using optical coherence tomography angiography

BACKGROUND: To investigate the difference in retinal nerve fiber layer (RNFL) thickness, choroidal thickness (CT) and superficial retinal vessels between thyroid-associated ophthalmopathy (TAO) patients and healthy controls. To identify the potential influencing factors for these parameters and evaluate their diagnostic abilities in TAO. METHODS: Twenty active TAO patients, 33 inactive TAO patients and 29 healthy participants were enrolled. TAO patients were divided according to the clinical activity score (CAS). RNFL thickness and CT were measured by HD-OCT, while foveal avascular zone (FAZ), vascular density and perfusion density were measured by optical coherence tomography angiography (OCTA). SPSS software was used for statistical analysis. RESULTS: Active TAO patients had thinner RNFL thickness than the other two groups (P < 0.001, P < 0.001). Both active and inactive TAO patients had significantly higher CT in the macular region (all P < 0.05). The FAZ area in the active TAO group was significantly larger than the other two groups (P = 0.045, P = 0.001). The inactive TAO group had significantly higher vascular density than the other two groups (all P < 0.05). With regard to the perfusion density, significant differences were observed in the temporal and inferior areas (P = 0.045, P = 0.001), as well as the average values (P = 0.032). The FAZ area was positively correlated with intraocular pressure (r = 0.274, P = 0.013), while it was negatively correlated with axial length (r = − 0.344, P = 0.002). The vascular density and perfusion density were not significantly correlated with different clinical variables (all P > 0.05). The AUC analysis indicated these parameters also exhibited a significant discriminatory power in TAO diagnosis. CONCLUSIONS: TAO patients had significant variations in RNFL thickness, choroidal thickness, FAZ area and superficial retinal vessels. These parameters appeared to be potential adjuncts in the evaluation of TAO patients.