Purpose: To evaluate peripapillary and macular vessel density in eyes with dysthyroid optic neuropathy (DON) and its correlation with visual function.
Methods: Patients diagnosed as thyroid-associated ophthalmopathy (TAO) with or without DON and healthy participants were recruited. All subjects underwent a complete ophthalmic examination and optical coherence tomography angiography centered on the fovea and the optic nerve head. Microvascular measurements were summarized as vessel density in the whole image and in each subfield. Visual function, including best-corrected visual acuity (BCVA), visual field (VF), and visual evoked potential (VEP), were assessed for all TAO patients. Areas under the receiver operating characteristic curves (AUROCs) were applied to evaluate the diagnostic accuracy of vessel density for DON.
Results: A total of 23 healthy eyes, 41 TAO eyes without DON, and 30 with DON were studied. The radial peripapillary capillary whole image vessel density (rpc-wiVD) and optic nerve head whole image vessel density (onh-wiVD) were significantly decreased in DON eyes compared with healthy and non-DON eyes (all P < 0.05). The decrease was more profound in the temporal peripapillary subfields than in others. The impairment of visual function (i.e. BCVA, VF, and VEP) was positively associated with the reduction of onh-wiVD and rpc-wiVD but not related to the rarefaction of macular microvasculature. Moreover, the onh-wiVD showed desirable diagnostic capacity to distinguish the DON eyes from NDON eyes (AUROC, 0.75).
Conclusions: A decrease in vessel density in the peripapillary area is evident in eyes with DON. The attenuation in peripapillary perfusion significantly correlates to the extent of visual impairment.