Quadrant asymmetry alteration of retinal degeneration in thyroid-associated ophthalmopathy

To measure alterations in quadrant asymmetry (QA) of retinal radial peripapillary capillary (RPC) density and to determine the association between subfield alterations and thyroid-associated ophthalmopathy (TAO).

Optical coherence tomography angiography images of 51 control eyes and 80 TAO eyes were analyzed to quantify RPC density. QA was defined as the difference between the maximum and minimum RPC densities among four subfields. Comparisons of RPC QA between groups and the associations of QA with the occurrence of TAO were analyzed. Linear regression was conducted to determine the association of subfield alterations with visual field mean deviation (MD).

QA of RPC density in TAO eyes was higher than in control eyes (9.58 ± 2.40 vs. 6.70 ± 2.01, P < 0.001), although no significant difference was observed in global RPC density between the TAO and control groups (P = 0.395). QA of RPC density demonstrated a high area under the curve (AUC = 0.816) for detecting TAO, whereas the AUC of global RPC density was only 0.564. Among the four subfields, only nasal RPC density showed a significant decrease in TAO eyes (48.03 ± 2.56 vs. 50.19 ± 2.79, P < 0.001). Univariate linear regression revealed that nasal RPC density was correlated with visual field MD (standardized coefficient = 0.243, P = 0.005), whereas RPC density in the other three subfields did not show significant correlations (all P ≥ 0.082).

Alterations in quadrant asymmetry of RPC density occurred in TAO, particularly decreased RPC density in the nasal subfield, which was significantly associated with visual field abnormalities in TAO.