Visual snow (VS) is a neurologic condition consisting of a constant positive visual disturbance described as “static” with diagnosis requiring exclusion of competing neurologic and ophthalmologic disorders. The authors describe the first case of visual snow-like symptoms in a patient following coronavirus disease 2019 (COVID-19) infection. He was found to have a transient subtle mild inflammatory reaction in the vitreous and optic nerve edema which resolved, but the VS persisted. Our findings suggest that COVID-19 may precipitate a transient autoimmune response in some patients with resultant ocular inflammation as well as long-term symptoms of VS. This has potential implications for the understanding and treatment of complications related to COVID-19 and in VS.
Visual snow (VS) is a neurologic condition consisting of a constant positive visual disturbance described as “static” or innumerable small dots throughout the visual field [
The case is a 28-year-old Chinese male with no past medical or psychiatric history presenting with complaints of constant “static” in his entire field of vision which he subsequently described as “a subtle overlay of an out-of-signal TV screen over my entire vision.” Symptoms began shortly following diagnosis with COVID-19 infection. The patient developed symptoms of COVID-19 (fever, cough, loss of sense of taste, and smell) on March 12, 2020, and was confirmed positive for COVID-19 via nasopharyngeal swab on March 20, 2020, by way of a nasopharyngeal swab tested for the coronavirus with reverse transcription-polymerase chain reaction RNA testing. He was subsequently hospitalized for 2 days and treated with IV azithromycin and hydroxychloroquine. The patient was discharged home and eventually tested negative for COVID-19 on April 11, 2020, also via nasopharyngeal swab and RNA, RT PCR. He then reported associated photophobia and palinopsia (after images). He denied prior visual symptoms prior to COVID-19 infection. He was also found to have decreased vision in the left eye by his optometrist and was referred for further evaluation.
The patient presented with best-corrected visual acuity (BCVA) of 20/20 in both eyes (OU). Intraocular pressure (IOP) was 17 mmHg in the right eye (OD) and 16 mmHg in the left eye (OS). Confrontation visual field was full, extraocular motility intact, and pupils equal reactive and reactive to light. Slit lamp exam (SLE) was with clear lens OU and with rare to trace white blood cells (WBCs) in the vitreous OU, but otherwise unremarkable. The cells were only noted with complete darkness and the slit beam and patient inspection of the vitreous over several minutes. Dilated fundus exam (DFE) was without posterior vitreous detachment (PVD) and retinal tear/break/hole, and the cup to disc (c/d) ratio was 0.6 OD and 0.7 OS (shown in Figures
Fundus photo of the (a) right and (b) left eyes at presentation. Late recirculation phase fluorescein angiogram taken at 3 minutes showing subtle staining of the nerve of the (c) right and (d) left eyes.
Optical coherence tomography with associated topographical map at presentation showing normal foveal contour with mild macular thickening of the (a) right eye and (b) left eye.
Octopus 30-2 visual field at presentation showing diffuse nonspecific suppression in the right eye (OD) and left eye (OS).
At a subsequent visit, ancillary tests confirmed retinal and optic nerve dysfunction including an electrooculogram (EOG) which showed suppression OD and borderline suppression OS with an Arden ratio of 1.41 (OD) and 1.85 (OS) (shown in Figure
Electrooculogram (EOG) showing suppression in the right eye (OD) and borderline suppression in the left eye (OS) with Arden ratio of 1.41 (OD) and 1.85 (OS).
Visual evoked potential/response (VEP/VER) demonstrated mild suppression in the right and left eyes (OD and OS, respectively).
Handheld flash full field electroretinogram (ERG) showing mild to moderate delayed implicit time with reduced photopic negative response OU.
Magnetic resonance imaging (MRI) of the brain and orbits with and without contrast identified mild sinus disease and an incidental 1.6 cm by 1.7 cm arachnoid cyst in the left anterior temporal region. Orbits were unremarkable, and optic nerve was negative for perineural contrast enhancement (shown in Figure
Magnetic resonance imaging (MRI) of head and orbits without evidence of optic nerve abnormality on (a) T2 image and without perineural enhancement of the optic nerve on (b) T1 with contrast and fat suppression.
The patient did report subjective improvement in symptoms with compliance with topical bromfenac and subjective worsening without the use of the topical bromfenac. Symptoms of “static” persisted on follow-up despite resolution of vitreous cells and a normal ophthalmologic exam. Symptoms continue to date of writing, which is more than ten months since the onset of symptoms.
COVID-19 is an ongoing viral pandemic that is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that is best known for its effect on the respiratory system. Associated symptoms include fever, cough, dyspnea, sputum production, myalgia, arthralgia, headache, diarrhea, rhinorrhea, and sore throat [
Emerging reports have also shown COVID-19 preceding the appearance of various autoimmune and autoinflammatory diseases, including pediatric inflammatory syndrome (PIMS) and Guillain-Barre syndrome [
Posterior uveitis has been reported in patients following COVID-19 infection, and there are reports suggesting retinal inflammation as well. Bakhoum et al. stated that patients have subclinical inflammation in the vitreous detected with SD-OCT, and this is consistent with our findings [
The ocular inflammation in our patient was subtle and difficult to detect—on first glance, the examination appeared normal, but careful inspection of the vitreous under dark-adapted conditions did reveal some cells. Additional data indicated posterior segment dysfunction including the abnormal ERG implicit times for both a- and b-waves, suppressed EOG amplitude, reduced VEP amplitude, generalized suppression of static visual field perimetry, and mild subtle leakage from the optic nerve and retinal vessels on fluorescein angiography. The patient did have a reduction of macular thickness on OCT studies after initiation of treatment with the topical nonsteroidal anti-inflammatory drop, bromfenac, but the visual snow symptoms persisted arguing that the posterior segment inflammation was not the cause of the visual snow symptoms. There is a case of posterior segment inflammation initially diagnosed as visual snow that ultimately was diagnosed as a case of uveitis, birdshot choroidopathy, with resolution of symptoms after treatment [
Visual snow has been reported to have a prevalence of 2.2% with symptoms commonly appearing during the late teenage years and early adulthood [
It should be noted that the patient was treated with azithromycin and hydroxychloroquine for COVID-19 prior to presentation to ophthalmology. These medications are not benign and are known to have neurocognitive effects which, however, are less likely contributors to the patient’s development of VS. Although clinical trials for azithromycin revealed no neurologic, audiometric, or ophthalmologic side effects [
In summary, we present a case of subtle posterior segment inflammation following COVID-19 infections with symptoms suggesting visual snow. Careful examination and ancillary testing confirmed the presence of retinal and optic nerve dysfunction. We propose that an autoimmune response was the culprit. Treatment with anti-inflammatory drops reduced symptoms. This has potential implications for the understanding and treatment of complications related to COVID-19.
The data used to support the findings of this study are available in the text and figures. Data or figures not included in the manuscript can be made available from the corresponding author upon request.
The authors confirm that the patient has given his written informed consent to publish his case report (including publication of images).
The following authors have no financial disclosures: KKB, MGA, and RPG.
All authors attest that they meet the current ICMJE criteria for Authorship.