| Background and objective: Optic coherence tomography (OCT) is an important ocular imaging technology in recent 20 years, Fourier-domain OCT brought improvement of OCT in the 21th century. Enhance depth imaging spectral domain OCT (EDI SD-OCT)and Optical coherence tomography angiography (OCTA) is new emerging technologies that are widely used in observing the blood flow of the choroid and retinal recently. As paired organs are not always perfectly symmetrical, an analysis of interocular symmetry can be a useful tool in clinical practice. Non-arteritic anterior ischemic optic neuropathy(NAION) and optic neuritis (ON) are the most common optic neuropathy, lots of clinical research demonstrated that vascular lesions participant in the pathology of the two optic nerve diseases. The objective of this research was to observe the vascular of the patients’macular and optic nerve via EDI SD-OCT and OCTA, analyze the symmetry of the two eyes, and explore the difference of the blood flow in NAION and ON.Methods:① Eighty six healthy Chinese adults (172 eyes) were prospectively enrolled in this study. They underwent peripapillary retinal nerve fiber layer (pRNFL)and peripapillary choroidal thickness (pCT) measurements via EDI SD-OCT, Subfoveal choroidal thickness (SFCT) measurements were also taken with a horizontal line scan centered on the macula. The pRNFLs, pCTs and SFCTs for the right and left eyes and the interocular differences were measured, and the agreement and correlations of the pRNFLs, pCTs and SFCTs between the right and left eyes were analyzed. ② Thirty six healthy Chinese adults (72 eyes) were prospectively enrolled in the study. They underwent the flow index of their macular and optic disc via OCTA, the interocular difference of the flow index was calculated, and the correlations of the sex, age and flow index were analyzed.③ Fourteen unilateral NAION patients were enrolled and undertaken the OCTA examination. The blood flow index of macular and optic disc, and pRNFL were acquired, symmetry of the two eyes were caculated, and the correlations between the pRNFL, visual field index and flow index were analyzed. ④ Nighty-six ON patients (145eyes) were recruited in the study, they were divided into two groups according to a serum AQP4-Ab assay, pRNFL, macular RNFL (mRNFL), macular retinal ganglion cell layer plus the inner plexiform layer (mGCIP) and SFCT were acquired via EDI SD-OCT, the difference of the two guoups were analyzed.⑤ Twenty one ON eyes from 21 patients were enrolled in the study. They underwent flow index measurement of their macular and optic nerve head via OCTA, the difference of the ON eyes and normal control eyes were analyzed, and the correlation of the pRNFLs, visual field index and flow index were analyzed. They were also divided into 2 groups according to serum AQP4-Ab assay, the difference of the retinal perfusion around optic disc and macular between the two groups were analyzed. ⑥ The blood flow index of the right and left eyes of the unilateral NAION and unilateral ON patients were calculated,and the interocular differences were analyzed. The asymmetry of the NAION, ON were also analyzed.Results:① The RNFL was statistically significantly thicker in the right eyes when compared to the left eyes in the temporal and nasal quadrant, and thinner on average in the nasal superior quadrant (p < 0.05). However, the differences in the choroidal thicknesses in all of the quadrants between the right and left eyes were not statistically significant. The pRNFLs and pCTs in all of the locations in the right eyes were significantly correlated with those in the left eyes.② There were no differences between two eyes in healthy Chinese adult of the flow index around macular and optic disc. The superficial non-flow area (NFA_S) in female was bigger than that in male (P<0.05).NFA_S and deep non-flow area (NFA_D) were positive correlated to the age (P<0.05).③Regarding of macular flow indexes, we did not find any differences between NAION eyes and the fellow eyes (P>0.05). However, there was significant difference in optic nerve head flow indexes between them (P<0.05),and there were significant correlation between visual field indexes and optic nerve head flow indexes (P<0.05).④ AQP4-Ab positive ON eyes had thinner pRNFL, mRNFL, mGCIP, but had thicker SFCT compared to AQP4-Ab negative ON (P<0.05).⑤ Most of the macular and optic nerve head flow index in the eyes affected with ON were significantly lower than in the healthy control eyes, except NFA S and NFA D; AQP4-Ab positive ON demonstrated less retinal perfusion than AQP4-Ab negative ON. ⑥ In the unilateral NAION and ON groups, the flow index of optic nerve head was decreased when compared to healthy control group(P<0.05). Regarding to macular flow index, NAION group showed no significant decrease compared to control group (P>0.05),but ON group showed significant decrease in superficial parafoveal vessel density (PVD S) (P<0.05). The ON group had more macular flow index reduction than NAION group, though P>0.05. However, NAION group had more optic nerve head flow index reduction than ON group (P<0.05).Conclusion: The pCT, SFCT and retinal perfusion around optic nerve head and macular did not differ significantly between right and left eyes in healthy Chinese adults,although inter ocular asymmetry of pRNFL existed in some quarter. Reduction of the optic nerve head blood flow was observed in NAION, however, no macular blood flow reduction was observed. However, reduction retinal perfusion was found not only around optic nerve head, but also around macular in ON eyes, AQP4-Ab negative ON demonstrated more retinal and choroidal blood flow than AQP4-Ab positive ON eyes.Compared to NAION group, ON group demonstrated more macular flow index reduction,but less optic nerve head flow index reduction. |
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