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

Completed

• Conditions: COVID-19

• Registration Number: NCT05747547
• Lead Sponsor: University Hospital Olomouc

Brief Summary

The study examines changes in retinal oximetry in patients after COVID-19 disease. It aims to analyze and quantify possible retinal microvascular abnormalities that may result from possible post-inflammatory damage to the endothelium of the vessels associated with COVID-19 disease. Retinal vascular involvement may indicate similar changes in the vascular system in other organs.

Detailed Description

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.

Study Timeline

• Study Start: 2022-08-01
• Study First Submitted: 2023-02-24
• Study First Submitted QC: 2023-02-24
• Study First Posted: 2023-02-28
• Primary Completion: 2023-05-01
• Study Completion: 2024-10-01
• Status Verified: 2025-05
• Last Update Submitted: 2025-05-22
• Last Update Posted: 2025-05-29

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 34

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

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Successful performing of retinal oximetry images in 90% of enrolled patients.	3 months	90% of captured fundus images of retinal oximetry are useful for subsequent analysis.
Successful analysis of retinal oxygen saturation in 90% of enrolled patients.	3 months	The parameters analyzed by retinal oximetry are arterial retinal oxygen saturation (%), venous retinal oxygen saturation (%), arterio-venous difference (%), arteriolar and venular diameter (µm).

Secondary Outcome Measures

Name	Time	Method
Successful analysis of optical coherence tomography in 90% of enrolled patients.	3 months	The parameters analyzed by optical coherence tomography are central retinal thickness (µm), ganglion cell layer thickness (µm), retinal nerve fiber layer thickness (µm), choroid thickness (µm) in the macular region and optic nerve head retinal nerve fiber layer thickness (µm).
Successful performing of optical coherence tomography and angiography in 90% of enrolled patients.	3 months	90% of captured images of optical coherence tomography and angiography are useful for subsequent analysis.
Successful analysis of optical coherence tomography angiography in 90% of enrolled patients.	3 months	The parameter analyzed by optical coherence tomography angiography is the size of foveal avascular zone (µm2).

Trial Locations

Locations (1)

Department of Ophthalmology, University Hospital Olomouc; 🇨🇿 Olomouc, Czechia