Assessment of alterations in the retina and vitreous in pre- and post-COVID-19 patients using swept-source optical coherence tomography and angiography: A comparative study.

Ocular manifestations have been well recognized in coronavirus disease 2019 (COVID-19) outbreak. Several studies have detected ocular manifestations in patients after COVID-19. However, little is known about the retinal and vitreal alterations in patients before and after COVID-19 infection. This study aimed to investigate the retinal and vitreal alterations in patients before and after contracting COVID-19 infection using swept-source optical coherence tomography (SS-OCT) and angiography (SS-OCTA). A total of 38 participants (76 eyes) were enrolled and followed-up 1 month after COVID-19 infection. Then, 26 patients (52 eyes) were evaluated 3 months after COVID-19 infection. Compared with the pre-COVID-19 status, patients with 1- and 3-month post-COVID-19 statuses had significant thinning of ganglion cell and inner plexiform layer, thickening of inner nuclear layer, a decrease in the vessel density (VD) of superficial vascular complex, and an increase in the VD of deep vascular complex. Meanwhile, alteration in parameters of foveal avascular zone (all p < 0.05) and hyper-reflective dots in the vitreous of 27 patients (54 eyes) (71.1% vs. pre-COVID-19, 34.2%, p = 0.006) were observed. These findings suggest significantly retinal and vitreal alterations occurred in patients after COVID-19 infection, possibly due to direct or indirect virus-induced injuries. Further longitudinal studies are required to investigate the long-term effects of COVID-19 infection on the human eyes.

Assessment of Outer Retina and Choroid Using Swept Source Optical Coherence Tomography and Angiography in Patients With Multiple Sclerosis.

BACKGROUND: For patients with multiple sclerosis (MS), both structure and microvasculature alterations in the inner retina have been investigated in several studies. However, little is known about the alterations in the outer retina and choroid. Hence, this study aimed to assess the outer retinal and choroidal changes in patients with MS with no history of optic neuritis (ON). METHODS: Patients with MS and healthy control participants were enrolled in this cross-sectional study. Quantitative analyses were performed using swept source optical coherence tomography and swept source optical coherence tomography angiography images to assess outer retina thickness (ORT) and choroid thickness (CT), vessel density (VD) of choriocapillaris, and choroidal vascularity index (CVI), which were then compared between the groups. RESULTS: A total of 37 participants with MS (72 eyes) and 74 healthy control participants (148 eyes) were included in this study. Compared with healthy controls, patients with MS with no history of ON showed reduced VD of the choriocapillaris and CVI. There was no significant difference in ORT and CT between 2 groups. Meanwhile, in patients with MS, no correlation between OCTA parameters and expanded disability status scale score were found in this study. CONCLUSIONS: Our study indicates that patients with MS with no history of optical neuritis have reduced choriocapillaris vessel density and decreased choroidal vascularity index without detectable alteration in outer retina thickness and choroid thickness. The findings complement the outer retinal and choroidal component of MS, providing deeper insight into the pathophysiology of MS.