Evaluation of Microcirculation in Optic Nerve Head Using Laser Speckle Flowgraphy in Active Thyroid Eye Disease

Abstract

Background. Laser speckle flowgraphy (LSFG) can be used to estimate optic nerve blood flow. This study used LSFG to evaluate optic nerve microcirculation in patients with thyroid eye disease (TED). Methods. This was a retrospective review of patients with active TED who underwent LSFG between October 2020 and June 2021. The mean blur rate (MBR) for different severities of active TED was analyzed by one-way analysis of variance (ANOVA). Results. A total of 30 patients (60 eyes) with a diagnosis of active TED who underwent LSFG were included. The mean age was 49 (range, 33–74) years. Mean best-corrected visual acuity was the worst in the group with sight-threatening active TED ( $0.29\pm 0.33$ logarithm of the minimum angle of resolution, $p=0.01$ ). The MBR-overall was the highest in the group with mild active TED ( $28.5\pm 2.7$ ), followed by that in the moderate to severe ( $23.6\pm 3.2$ ), and in the sight-threatening ( $20.2\pm 4.3$ ) active TED groups ( $p<0.001$ ). The MBR-vessel was 57.1, 47.0, and 39.3 in the mild, moderate to severe, and sight-threatening active TED groups, respectively ( $p<0.001$ ). The MBR-tissue was 16.9, 14.4, and 12.0 in the mild, moderate to severe, and sight-threatening active TED groups, respectively ( $p<0.001$ ). Conclusions. This study demonstrates that optic nerve blood flow is lower with more severe active TED. In addition, LSFG is an effective, objective, and noninvasive method for evaluating the severity of TED.