The study examines changes in retinal oximetry in patients after COVID-19 disease. Itaims to analyze and quantify possible retinal microvascular abnormalities that may resultfrom possible post-inflammatory damage to the endothelium of the vessels associated withCOVID-19 disease. Retinal vascular involvement may indicate similar changes in thevascular system in other organs.
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.
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).
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
Department of Ophthalmology, University Hospital Olomouc
Olomouc, Czechia
Zuzana Schreiberova, MD, Principal Investigator
University Hospital Olomouc and Palacky University Olomouc