A Pilot Study of Subclinical Non-Capillary Peripapillary Perfusion Changes in Thyroid-Related Orbitopathy Detected Using Optical Coherence Tomography Angiography

Alexander Pinhas,1,2 Jorge S Andrade Romo,1 Giselle Lynch,1,3 Davis B Zhou,1,3 Maria V Castanos Toral,1 Phillip A Tenzel,1 Oscar Otero-Marquez,1 Shoshana Yakubova,1,4 Alexander Barash,1 David Della Rocca,1 Robert Della Rocca,1 Toco YP Chui,1 Richard B Rosen,1 Harsha S Reddy1 1Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA; 2Department of Ophthalmology, State University of New York Downstate Medical Center, Brooklyn, NY, USA; 3Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, USA; 4Department of Biology, Macaulay Honors College at City University of New York Queens College, Flushing, NY, USACorrespondence: Harsha S Reddy, Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, 310 E 14th St, New York, NY, 10003, USA, Tel +1 212-979-4284, Fax +1 212-966-6295, Email hreddy@nyee.eduPurpose: Hemodynamic changes surrounding the optic nerve head are known to occur in thyroid-related orbitopathy (TRO). This pilot study explores the capillary and non-capillary peripapillary perfusion changes of the retina in TRO eyes without dysthyroid optic neuropathy (DON) using optical coherence tomography angiography (OCT-A).Methods: Non-capillary and capillary peripapillary perfusion densities were calculated using single 4.5 × 4.5mm en face “RPC layer” OCT-A scans of 8 TRO patients without DON (8 eyes, mean age 40.6 years, range 23– 69 years). Results were compared to a previously published dataset of 133 healthy controls (133 eyes, mean 41.5 years, range 11– 83 years). The strength of association was measured between OCT-A perfusion densities and clinical measures of TRO.Results: Non-capillary peripapillary perfusion density in TRO eyes was found to be significantly decreased compared to healthy controls (TRO group 15.4 ± 2.9% vs controls 21.5 ± 3.1%; p < 0.0001). Capillary peripapillary perfusion densities showed no significant difference (TRO group 42.5 ± 1.8% vs controls 42.5 ± 1.5%; p = 1.0). Clinical measures of disease did not correlate well with OCT-A perfusion densities (p> 0.05).Conclusion: These findings may represent decreased blood flow and subclinical ischemia to the optic nerve. We discuss possible pathogenic mechanisms of thyroid-related vasculopathy, including vessel wall thickening due to immunologically-induced media enlargement.Keywords: thyroid-related orbitopathy, optical coherence tomography angiography, peripapillary microvasculature, thyroid-related vasculopathy