Californian Study Shows That Post-COVID Individuals Are At A Risk Of Developing Retinal Vascular Occlusions or ‘Eye Strokes’!

A new study by researchers from Southern California Permanente Medical Group, Pasadena -California and Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena-California has alarmingly found that post-COVID individuals are at a risk of developing retinal vascular occlusions or ‘eye strokes’! The incidence of retinal vein occlusion was much higher in the 6 months after COVID-19 infection compared with the 6 months before infection.


 
Retinal vascular occlusion is a blockage of one of the retinal blood capillaries that carry oxygenated blood or from the heart to your retina or vice versa, deoxygenated blood from the eyes to the heart. A blockage in the main artery of your retina is called a central retinal artery occlusion and when a vein in the retina becomes blocked, it's called retinal vein occlusion.
 
Such blockages can cause blurry vision or even sudden permanent blindness in that eye and is sometimes called as an eye stroke. Such blockages can occur because the capillaries of the eye are too narrow. It is more likely to occur in people with diabetes, and possibly high blood pressure, high cholesterol levels, or other health problems that affect blood flow.
 
It is already known that COVID-19 is associated with systemic vascular damage; however, the risk posed to the retinal vasculature remains incompletely understood.
 
The study team’s main aim was to assess if there is a change in the incidence of retinal vascular occlusions after COVID-19 infection.
 
This cohort study at an integrated health care organization (Kaiser Permanente Southern California) included patients without a history of retinal vascular occlusion who were diagnosed with COVID-19 infection between January 20, 2020, and May 31, 2021. Patients were excluded if they had a history of retinal artery occlusions (RAOs) or retinal vein occlusions (RVOs) more than 6 months before their COVID-19 diagnosis or if they were enrolled in Kaiser Permanente Southern California for less than 6 months before COVID-19 diagnosis.
 
The change in the average biweekly incidence of new RAOs and RVOs after COVID-19 diagnosis. Adjusted incidence rate ratios (IRRs) were calculated to compare the incidence of retinal vascular occlusions before and after COVID-19 diagnosis after accounting for baseline demographic characteristics, medical history, and hospitalization.
 
A total of 432 515 patients diagnosed with COVID-19 infection were included in this study. The mean (SD) age was 40.9 (19.2) years, and 231 767 patients (53.6%) were women.
 
The study findings showed that sixteen patients had an RAO (crude incidence rate, 3.00 per 1 000 000 patients), and 65 had an RVO (crude incidence rate, 12.20 per 1 000 000 patients) in the 6 months after COVID-19 diagnosis. The incidence of new RVOs was higher in the 6 months after COVID-19 infection compared with the 6 months before infection after adjusting for age; sex; self-reported race and ethnicity; body mass index; history of diabetes, hypertension, or hyperlipidemia; and hospitalization (adjusted IRR, 1.54; 95% CI, 1.05-2.26; P = .03). There was a smaller increase in the incidence of RAOs after COVID-19 diagnosis (IRR, 1.35; 95% CI, 0.64-2.85; P = .44). The peak incidence of RAOs and RVOs occurred 10 to 12 weeks and 6 to 8 weeks after COVID-19 diagnosis, respectively.
 
The study findings suggest that there was an increase in the incidence of RV Os after COVID-19 infection. Further large, epidemiologic studies are warranted to better define the association between retinal thromboembolic events and COVID-19 infection.
 
The study findings were published in the peer reviewed journal: in JAMA Ophthalmology. https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2790988
 
Dr Bobeck S. Modjtahedi, M.D., from the Southern California Permanente Medical Group in Pasadena, and colleagues conducted a cohort study involving 432,515 patients without a history of retinal vascular occlusion who were diagnosed with COVID-19 between Jan. 20, 2020, and May 31, 2021. The change in average biweekly incidence of new retinal artery occlusions (RAOs) and RVOs after COVID-19 was examined.
 
The study team found that 16 patients had an RAO and 65 had an RVO (crude incidence rates, 3.00 and 12.20 per 1,000,000 patients, respectively).

After adjustment for age; sex; self-reported race and ethnicity; body mass index; history of diabetes, hypertension, or hyperlipidemia; and hospitalization, there was a higher incidence of new RVOs in the six months after COVID-19 infection compared with the six months before infection (adjusted incidence rate ratio, 1.54; 95 percent confidence interval, 1.05 to 2.26; P = 0.03).
 
Also, a smaller, nonsignificant, increase in the incidence of RAOs was seen after COVID-19 diagnosis (adjusted incidence rate ratio, 1.35; 95 percent confidence interval, 0.64 to 2.85; P = 0.44). At 10 to 12 weeks and six to eight weeks after COVID-19 diagnosis, the peak incidence of RAOs and RVOs occurred, respectively.
 
Dr Modjtahedi told Thailand Medical News, "The study findings provide further evidence of the prothrombotic state induced by COVID-19 and indicate that the post-infection impacts may last several weeks. Large epidemiologic studies are warranted to better define the association between retinal thromboembolic events and COVID-19 infection."



In an accompanying commentary of the study in the same journal, researchers from University of Michigan Medical School commented,  “Vascular damage underlies the damage caused by COVID-19 to multiple organs via 2 main mechanisms: disseminated intravascular coagulation–like reaction leading to hypercoagulability and direct viral infection of the endothelial cells leading to a vasculitis-like picture. Furthermore, patients with COVID-19 are predisposed to embolism formation due to intravascular coagulation and hypoxia. The combination of COVID-19’s vascular damage and higher embolism formation tendencies can hypothetically increase the risk of retinal vascular occlusion.”
https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2790986
 
Already a number of past studies have also indicated a correlation between COVID-19 and retinal vascular occlusions.
https://pubmed.ncbi.nlm.nih.gov/32572363/
 
https://pubmed.ncbi.nlm.nih.gov/33225111/
 
Thailand Medical News strongly recommends that all post COVID individuals maintain frequent health screenings not only for the eyes but also for various other organs and conditions.
 
For more on Post-COVID Eye Problems, keep on logging to Thailand Medical News.