COVID-19NCT05747547
Retinal Vascular Changes in Patients After Coronavirus Disease 2019 (COVID-19)
An observational study of COVID-19, run by University Hospital Olomouc at 1 site in Czechia.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- COVID-19
- What is being tested?
- Central visual acuity, Intraocular pressure measurement and Slit lamp examination
- How many people
- 34 participants
- Where
- 1 siteCzechia
- Study dates
- 1 Aug 2022to 1 Oct 2024
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
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.
Who may be able to join
- age over 18 years
- history of laboratory-confirmed SARS-CoV2-infection
- transparent ocular media allowing for fundus photography
- signed informed consent
Who cannot join
- 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
Show all 10Show fewer
- 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
Trial locations and contacts
1 site in 1 country.
Czechia1 site
Department of Ophthalmology, University Hospital Olomouc
Olomouc
About this study
Official title: 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.
Read the 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.
- Conditions
- COVID-19
- Being tested
- Central visual acuity, Intraocular pressure measurement, Slit lamp examination, Retinal oximetry, Optical coherence tomography and angiography
- Medical subject headings
- COVID-19
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Central visual acuityDiagnostic test
Measurement of central visual acuity using ETDRS (Early Treatment Diabetic Retinopathy Study) optotypes or Snellen optotype chart.
Intraocular pressure measurementDiagnostic test
Measurement of intraocular pressure using non-contact Canon TX-20P tonometer.
Slit lamp examinationDiagnostic test
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).
Retinal oximetryDiagnostic test
Performing of retinal oximetry with an Oxymap T1 instrument (Oxymap ehf.) paired with a Topcon TRC-50DX retinal camera.
Optical coherence tomography and angiographyDiagnostic test
Performing of optical coherence tomography and angiography with the Spectralis Optical Coherence Tomography Plus (Heidelberg Engineering).
| Study group | Role | What they receive |
|---|---|---|
| mild disease | asymptomatic or paucisymptomatic patients with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection (SARS-CoV2-infection) who received outpatient care Receives: Diagnostic Test: Central visual acuity; Diagnostic Test: Intraocular pressure measurement; Diagnostic Test: Slit lamp examination; Diagnostic Test: Retinal oximetry; Diagnostic Test: Optical coherence tomography and angiography | |
| moderate disease | patients with laboratory-confirmed SARS-CoV2-infection and radiology-confirmed pneumonia who did not require extracorporeal membrane oxygenation Receives: Diagnostic Test: Central visual acuity; Diagnostic Test: Intraocular pressure measurement; Diagnostic Test: Slit lamp examination; Diagnostic Test: Retinal oximetry; Diagnostic Test: Optical coherence tomography and angiography | |
| severe disease | patients with laboratory-confirmed SARS-CoV2-infection and acute respiratory distress syndrome who required extracorporeal membrane oxygenation Receives: Diagnostic Test: Central visual acuity; Diagnostic Test: Intraocular pressure measurement; Diagnostic Test: Slit lamp examination; Diagnostic Test: Retinal oximetry; Diagnostic Test: Optical coherence tomography and angiography |
What is being measured
The primary outcome is the main question the study is designed to answer.
Successful performing of retinal oximetry images in 90% of enrolled patients.
90% of captured fundus images of retinal oximetry are useful for subsequent analysis.
Measured: 3 months
Successful analysis of retinal oxygen saturation in 90% of enrolled patients.
The parameters analyzed by retinal oximetry are arterial retinal oxygen saturation (%), venous retinal oxygen saturation (%), arterio-venous difference (%), arteriolar and venular diameter (µm).
Measured: 3 months
Secondary outcomes (3)
Successful performing of optical coherence tomography and angiography in 90% of enrolled patients.
90% of captured images of optical coherence tomography and angiography are useful for subsequent analysis.
Measured: 3 months
Successful analysis of optical coherence tomography in 90% of enrolled patients.
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).
Measured: 3 months
Successful analysis of optical coherence tomography angiography in 90% of enrolled patients.
The parameter analyzed by optical coherence tomography angiography is the size of foveal avascular zone (µm2).
Measured: 3 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Feb 2023
- Study start1 Aug 2022
- Primary completion1 May 2023
- Study completion1 Oct 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for COVID-19Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 34 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Hospital Olomouc
- Sponsor type
- University, hospital or other
- Collaborators
- Palacky University
- Responsible party
- Principal investigator, Zuzana Schreiberova, University Hospital Olomouc
- Investigators
- Zuzana Schreiberova, MD, Principal investigator, University Hospital Olomouc and Palacky University Olomouc
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05747547
- Sponsor's protocol ID
- 9/23
- Status last verified
- May 2025
- First submitted
- 24 Feb 2023
- Last updated
- 29 May 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 29 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Retinal Vascular Changes in Patients After Coronavirus Disease 2019 (COVID-19) Based on Retinal Oximetry
- ClinicalTrials.gov ID
- NCT05747547
- Acronym / sponsor ID
- 9/23
- Conditions
- COVID-19
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 34 participants (actual)
- Lead sponsor
- University Hospital OlomoucUniversity, hospital or other
- Collaborators
- Palacky University
- Study start
- 1 Aug 2022 (actual)
- Primary completion
- 1 May 2023 (actual)
- Study completion
- 1 Oct 2024 (actual)
- First posted
- 28 Feb 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| mild disease | – | Diagnostic Test: Central visual acuity, Diagnostic Test: Intraocular pressure measurement, Diagnostic Test: Slit lamp examination, Diagnostic Test: Retinal oximetry, Diagnostic Test: Optical coherence tomography and angiographyasymptomatic or paucisymptomatic patients with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection (SARS-CoV2-infection) who received outpatient care |
| moderate disease | – | Diagnostic Test: Central visual acuity, Diagnostic Test: Intraocular pressure measurement, Diagnostic Test: Slit lamp examination, Diagnostic Test: Retinal oximetry, Diagnostic Test: Optical coherence tomography and angiographypatients with laboratory-confirmed SARS-CoV2-infection and radiology-confirmed pneumonia who did not require extracorporeal membrane oxygenation |
| severe disease | – | Diagnostic Test: Central visual acuity, Diagnostic Test: Intraocular pressure measurement, Diagnostic Test: Slit lamp examination, Diagnostic Test: Retinal oximetry, Diagnostic Test: Optical coherence tomography and angiographypatients with laboratory-confirmed SARS-CoV2-infection and acute respiratory distress syndrome who required extracorporeal membrane oxygenation |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- 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.
Key inclusion criteria (4 listed)
- age over 18 years
- history of laboratory-confirmed SARS-CoV2-infection
- transparent ocular media allowing for fundus photography
- signed informed consent
Key exclusion criteria (10 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Central visual acuityMeasurement of central visual acuity using ETDRS (Early Treatment Diabetic Retinopathy Study) optotypes or Snellen optotype chart. | Diagnostic test | mild disease, moderate disease, severe disease |
| Intraocular pressure measurementMeasurement of intraocular pressure using non-contact Canon TX-20P tonometer. | Diagnostic test | mild disease, moderate disease, severe disease |
| Slit lamp examinationSlit 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 | mild disease, moderate disease, severe disease |
| Retinal oximetryPerforming of retinal oximetry with an Oxymap T1 instrument (Oxymap ehf.) paired with a Topcon TRC-50DX retinal camera. | Diagnostic test | mild disease, moderate disease, severe disease |
| Optical coherence tomography and angiographyPerforming of optical coherence tomography and angiography with the Spectralis Optical Coherence Tomography Plus (Heidelberg Engineering). | Diagnostic test | mild disease, moderate disease, severe disease |
Primary outcome
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.
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 secondary outcomes
Successful performing of optical coherence tomography and angiography in 90% of enrolled patients.
Time frame: 3 months
Successful analysis of optical coherence tomography in 90% of enrolled patients.
Time frame: 3 months
Successful analysis of optical coherence tomography angiography in 90% of enrolled patients.
Time frame: 3 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 May 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Zuzana Schreiberova, MD principal investigator
University Hospital Olomouc and Palacky University Olomouc
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of COVID-19, run by University Hospital Olomouc at 1 site in Czechia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 29 May 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Czechia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Successful performing of retinal oximetry images in 90% of enrolled patients. (time frame: 3 months). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 May 2025.