Retinal Vascular Changes in Patients After Coronavirus Disease 2019 (COVID-19)

The retinal blood vessels are the only blood vessels in the body that can be observed directly. Patients with COVID-19 pneumonia have been shown to have reduced macular vessel density in the foveal region. As a result, some layers of the retina atrophy, reducing oxygen consumption by the retina. Based on this, it is expected that patients after COVID-19 pneumonia, or after a more severe course of the disease, will have normal arterial retinal oxygen saturation but higher venous retinal oxygen saturation and lower arterio-venous difference than patients after mild disease.

Inclusion criteria

• age over 18 years
• history of laboratory-confirmed SARS-CoV2-infection
• transparent ocular media allowing for fundus photography
• signed informed consent

Exclusion criteria

• known eye disease that has been shown to affect retinal oxygen saturation (diabetic retinopathy, vascular occlusions, use of antiglaucoma drugs)
• any other serious eye disease (advanced or decompensated glaucoma, retinitis pigmentosa, age-related macular degeneration, ocular tumors)
• reduced transparency of the ocular media limiting the visualization of the ocular background and preventing a good quality image from being taken (severe dry eye syndrome, corneal scarring, cataract, significant vitreous haze, vitreous hemorrhage)
• significant refractive error not allowing for sharpening of imaging examinations
• previous intraocular surgery except cataract surgery if performed more than 3 months before the examination
• previous intravitreal application of anti-vascular endothelial growth factor therapy or laser photocoagulation of the retina
• previous severe eye injury
• acute eye infection
• known systemic disease affecting retinal oxygen saturation or causing changes in the ocular background (chronic obstructive pulmonary disease, multiple myeloma, malignant hypertension, hyperglobulinemia)
• pregnancy, breastfeeding