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

May 22, 2025 updated by: Zuzana Schreiberova, University Hospital Olomouc

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

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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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 Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
34

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Czechia
      • Olomouc, Czechia
        • Department of Ophthalmology, University Hospital Olomouc

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Groups will be recruited from patients examined at the Department of Respiratory Diseases and Tuberculosis of University Hospital Olomouc at the outpatient check-up.

Description

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 Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
mild disease
asymptomatic or paucisymptomatic patients with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection (SARS-CoV2-infection) who received outpatient care
Diagnostic test: Central visual acuity
Measurement of central visual acuity using ETDRS (Early Treatment Diabetic Retinopathy Study) optotypes or Snellen optotype chart.
Diagnostic test: Intraocular pressure measurement
Measurement of intraocular pressure using non-contact Canon TX-20P tonometer.
Diagnostic test: Slit lamp examination
Slit lamp examination of the anterior and posterior segment of the eye after pharmacological dilation of the pupil using application of short-time mydriatics (1% tropicamide and 10% phenylephrine).
Diagnostic test: Retinal oximetry
Performing of retinal oximetry with an Oxymap T1 instrument (Oxymap ehf.) paired with a Topcon TRC-50DX retinal camera.
Diagnostic test: Optical coherence tomography and angiography
Performing of optical coherence tomography and angiography with the Spectralis Optical Coherence Tomography Plus (Heidelberg Engineering).
moderate disease
patients with laboratory-confirmed SARS-CoV2-infection and radiology-confirmed pneumonia who did not require extracorporeal membrane oxygenation
Diagnostic test: Central visual acuity
Measurement of central visual acuity using ETDRS (Early Treatment Diabetic Retinopathy Study) optotypes or Snellen optotype chart.
Diagnostic test: Intraocular pressure measurement
Measurement of intraocular pressure using non-contact Canon TX-20P tonometer.
Diagnostic test: Slit lamp examination
Slit lamp examination of the anterior and posterior segment of the eye after pharmacological dilation of the pupil using application of short-time mydriatics (1% tropicamide and 10% phenylephrine).
Diagnostic test: Retinal oximetry
Performing of retinal oximetry with an Oxymap T1 instrument (Oxymap ehf.) paired with a Topcon TRC-50DX retinal camera.
Diagnostic test: Optical coherence tomography and angiography
Performing of optical coherence tomography and angiography with the Spectralis Optical Coherence Tomography Plus (Heidelberg Engineering).
severe disease
patients with laboratory-confirmed SARS-CoV2-infection and acute respiratory distress syndrome who required extracorporeal membrane oxygenation
Diagnostic test: Central visual acuity
Measurement of central visual acuity using ETDRS (Early Treatment Diabetic Retinopathy Study) optotypes or Snellen optotype chart.
Diagnostic test: Intraocular pressure measurement
Measurement of intraocular pressure using non-contact Canon TX-20P tonometer.
Diagnostic test: Slit lamp examination
Slit lamp examination of the anterior and posterior segment of the eye after pharmacological dilation of the pupil using application of short-time mydriatics (1% tropicamide and 10% phenylephrine).
Diagnostic test: Retinal oximetry
Performing of retinal oximetry with an Oxymap T1 instrument (Oxymap ehf.) paired with a Topcon TRC-50DX retinal camera.
Diagnostic test: Optical coherence tomography and angiography
Performing of optical coherence tomography and angiography with the Spectralis Optical Coherence Tomography Plus (Heidelberg Engineering).

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Successful performing of retinal oximetry images in 90% of enrolled patients.
Time Frame: 3 months
90% of captured fundus images of retinal oximetry are useful for subsequent analysis.
3 months
Successful analysis of retinal oxygen saturation in 90% of enrolled patients.
Time Frame: 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).
3 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Successful performing of optical coherence tomography and angiography in 90% of enrolled patients.
Time Frame: 3 months
90% of captured images of optical coherence tomography and angiography are useful for subsequent analysis.
3 months
Successful analysis of optical coherence tomography in 90% of enrolled patients.
Time Frame: 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).
3 months
Successful analysis of optical coherence tomography angiography in 90% of enrolled patients.
Time Frame: 3 months
The parameter analyzed by optical coherence tomography angiography is the size of foveal avascular zone (µm2).
3 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University Hospital Olomouc

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Palacky University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Zuzana Schreiberova, MD, University Hospital Olomouc and Palacky University Olomouc

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
August 1, 2022

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 1, 2023

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
October 1, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 24, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 24, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 28, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 29, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 22, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 9/23

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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