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New findings on retinal microvascular changes in patients with primary COVID-19 infection: a longitudinal study
Chenxi Zhang1,2, Shiyu Cheng1,2, Huan Chen1,2
1Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
Insights
Mild COVID-19 infection can temporarily affect the retinal microvasculature, increasing blood flow early in recovery. These changes are reversible, returning to normal levels within two months post-infection.
Area of Science:
- Ophthalmology
- Vascular Biology
- Infectious Diseases
Background:
- The impact of COVID-19 on ocular health, particularly retinal microvasculature, requires further investigation.
- Longitudinal studies are crucial for understanding the dynamic changes in retinal vasculature following infection.
Purpose of the Study:
- To investigate longitudinal alterations in retinal microvasculature in patients with primary COVID-19 infection.
- To assess the reversibility of these microvascular changes post-infection.
Main Methods:
- A cohort study involving comprehensive ophthalmologic examinations and fundus imaging, including SS-OCT and SS-OCTA.
- Follow-up assessments were conducted within one week and two months after recovery from COVID-19.
Main Results:
- No clinical retinal microvasculopathy was observed.
- A transient, significant increase in macular vessel density was noted one week post-infection, returning to baseline by two months.
- Central macular thickness and retinal layer volumes showed transient decreases early post-infection, normalizing by two months.
Conclusions:
- Mild COVID-19 infection can cause temporary and reversible changes in retinal microvasculature.
- A transient increase in retinal blood flow occurs during early recovery, normalizing within two months.
Purpose:
To investigate the longitudinal alterations of retinal microvasculature in patients with primary coronavirus disease 2019 (COVID-19) infection.
Methods:
A cohort of participants, who had never been infected with COVID-19, was recruited between December 2022 and May 2023 at Peking Union Medical College Hospital in Beijing, China. Participants underwent comprehensive ophthalmologic examinations and fundus imaging, which included color fundus photography, autofluorescence photography, swept-source optical coherence tomography (SS-OCT) and SS-OCT angiography (SS-OCTA). If participants were infected with COVID-19 during the study, follow-ups with consistent imaging modality were conducted within one week and two months after recovery from the infection.
Results:
31 patients (61 eyes), with a mean age of 31.0 ± 7.2 years old, were eligible for this study. All participants contracted mild COVID-19 infection within one month of baseline data collection. The average period was 10.9 ± 2.0 days post-infection for the first follow-up and 61.0 ± 3.5 days for the second follow-up. No clinical retinal microvasculopathy features were observed during the follow-ups. However, SS-OCTA analysis showed a significant increase in macular vessel density (MVD) from 60.76 ± 2.88% at baseline to 61.59 ± 3.72%(p=0.015) at the first follow-up, which subsequently returned to the baseline level of 60.23 ± 3.33% (p=0.162) at the two-month follow-up. The foveal avascular zone (FAZ) remained stable during the follow-ups with areas of 0.339 ± 0.097mm2, 0.342 ± 0.093mm2, and 0.344 ± 0.098mm2 at the baseline, first follow-up (p=0.09) and second follow-up (p=0.052), respectively. Central macular thickness, cube volume and ganglion cell-inner plexiform layer showed a transient decrease at the first follow-up(p<0.001, p=0.039, p=0.002, respectively), and increased to baseline level at the two-month follow-up(p=0.401, p=0.368, p=0.438, respectively).
Conclusion:
Mild COVID-19 infection may temporarily and reversibly impact retinal microvasculature, characterized by a transient increase in retinal blood flow during the early recovery phase, which returns to the pre-infection level two months post-infection.
