Peripapillary and Macular Vessel Density in Dysthyroid Optic Neuropathy: An Optical Coherence Tomography Angiography Study

Abstract

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.

Reduced macular inner retinal thickness and microvascular density in the early stage of patients with dysthyroid optic neuropathy

“…In the current study, we found that the RCDs in both the SRCL and DRCL of the two TAO groups were lower than in the controls. Similar results were also reported by Zhang et al [31] though they only detected the vascular density in the SRCL. In addition, we found that the RCDs in SRCL and the GCC thickness were positively correlated in the TAZ region and in the T, I, and N sectors.…”

“…We found that, in support of the speculation by Meirovitch et al [12], the thicknesses of the NFL, GCL + IPL, and GCC were all decreased in both TAO subgroups and are likely responsible for the thinning of the whole retina around the macula. Zhang et al [31] also reported similar decreases of the GCC layer thickness in the DON group. Mechanical compression of the retina by orbital contents, decreased blood supply, as well as secondary increases in IOP were considered as possible reasons for ganglion cell atrophy resulting in macular thinning in the eyes with TAO [12].…”

“…Most previous studies focused on TAO patients or only DON patients. Seldom has a study been performed to record the characteristics of TAO patients without DON and who appear normal with respect to visual function, optic nerve head appearance, and CT scan results [31]. We found that both the inner intra-retinal layer thickness and the RCDs in SRCL and DRCL were significantly decreased in almost all regions and sectors compared to the controls.…”

The retinal vasculature pathophysiological changes in vision recovery after treatment for indirect traumatic optic neuropathy patients

“…The damage to the optic nerve due to intraneural edema alters microvasculature and interruption of direct axoplasmic transport. Also, vascular insufficiency resulted from the altered microvasculature might be an important pathogenic mechanism in other optic neuropathies [20,23,24], which implies that the abnormal hemodynamic state participates in the course of ITON, and the decompression surgery is effective by improving the retinal vasculature alteration. The spectrophotometric retinal oximetry and the optical coherence tomography angiography (OCT-A) are both noninvasive diagnostic tools to evaluate hemodynamic changes in eye diseases.…”

The Therapeutic Effect of Combination of Orbital Decompression Surgery and Methylprednisolone Pulse Therapy on Patients with Bilateral Dysthyroid Optic Neuropathy

“…e pathogenesis of DON includes multiple factors. Bulging of orbital connective tissue and fat leads to hypertrophy of extraocular muscle and obstruction of venous return which in turn induces high intraorbital pressure and decreased vessel density in the peripapillary area [5]. Orbital crowding may also result in increasing pressure in the episcleral veins, which may lead to increasing intraocular pressure (IOP) and optic nerve compression [6].…”