COVID-19 and the eyes: scientific studies reveal retinal involvement

COVID-19 and eyes: background

The outbreak of COVID-19 (COronaVIrus Disease 19) caused by the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) strain is currently the focus of much scientific research worldwide. The ophthalmological implications of this syndrome have not yet been fully explored, although the eye and lachrymal secretions, assessed as a gateway and source of infection for the virus, have been the subject of study and debate by many authors.

It has been shown that COVID-19 and the eyes are closely linked: the infection can affect various body districts including the eye in which it most commonly causes conjunctivitis. SARS-CoV-2, in fact, can cause inflammation of the conjunctiva causing redness and itching of the eyes. Although annoying, conjunctivitis is still a benign condition that rarely impairs vision and is often self-limiting.

A more worrying aspect emerges, however, from a very recent study published in the authoritative journal The Lancetin which an involvement of the retina of the eye is demonstrated in patients with COVID-19.

Retina and COVID-19

Using optical coherence tomography (OCT), a non-invasive imaging technique useful for demonstrating retinal changes subclinical to systemic conditions such as diabetes, the study authors evaluated patients with COVID-19. The study analysed by OCT the retinal changes of 12 adults (6 men and 6 women), aged 25-69 years, examined 11-33 days after the onset of COVID-19 symptoms. All patients presented with fever, asthenia and dyspnoea and 11 patients also presented with anosmia. Two patients were hospitalised, but none required intensive care and all patients had normal blood parameters at the time of ophthalmological evaluation. For the OCT examination, the study used two different devices: DRI-OCT Triton Swept Source (Topcon Tokyo, Japan) and XR Avanti SD-OCT (Optovue, Fremont, CA, USA). The OCT examination showed in all patients hyper-reflective lesions at the level of the ganglion cells and inner plexiform layers of the retina of the eye and most prominently at the level of the macular papillus bundle. In addition, four patients had thin cottony exudates and microhaemorrhages along the retinal arch. Visual acuity and pupillary reflexes were normal in all eyes examined and no symptoms or signs of intraocular inflammation were detected.

COVID-19 and eyesother studies and evidence 

This study, which is the first to report possible retinal damage associated with Sars-CoV-2 infection in humans, has been followed by others. Some authors have, in fact, reported two patients with acute paracentral media maculopathy and acute macular neuroretinopathy following SARS-CoV-2 infection. Another study, which evaluated 27 asymptomatic subjects with previous COVID-19 respiratory tract infection, showed cottony exudates in the retina in six patients.

The evidence so far suggests that retinal involvement in COVID-19 disease is certainly plausible. This possibility is of particular importance in patients at high risk for retinopathy, such as patients with diabetes and hypertension, but is certainly relevant for anyone given the possible serious functional consequences that retinal damage can cause. In light of this, greater emphasis should be placed on clinically significant ocular symptoms, such as scotoma, which may indicate the need for retinal examination and follow-up testing after recovery from COVID-19.

Bibliography

• Paula M Marinho et al. Retinal findings in patients with COVID-19. The Lancet Vol 395 May 23, 2020
• Michael Karampelas, Maria Dalamaga, Irene Karampela. Does COVID-19 Involve the Retina? Ophthalmol Ther (2020) 9:693-695.

Dr. Carmelo Chines
Direttore responsabile