Abstract
Background: To report occurrence of peculiar visual symptoms of visual snow syndrome in patients following COVID-19 disease.
Methods: We report five patients who suffered from a mild form of COVID-19 disease who after recovery presented with peculiar visual symptoms. These patients underwent detailed history-taking, with complete ophthalmic and neurologic check-up and investigation.
Results: Five patients with age ranging from 10-54 years were seen 4-24 months after a self-reported mild attack of COVID-19 disease. The diagnosis was confirmed on RT-PCR test for SARS-CoV-2 virus. The peculiar symptoms reported were seeing constant static-like visual snow, palinopsia, light sensitivity, and dizziness in bright light. The visual acuity was 20/20. One patient was known to have sectoral retinitis pigmentosa, and another had undergone scleral buckle surgery for retinal detachment many years ago. The ocular examination was normal in the other 3 patients. None had any neurologic abnormality and only one had a history of migraine. Patients were educated about the benign nature of these symptoms and were counseled.
Conclusions: COVID-19 disease can possibly act as a precipitating cause for visual snow syndrome. Awareness of this syndrome can help the ophthalmic healthcare professional counsel these bewildered patients.
Introduction
The coronavirus global pandemic had a profound impact on the mental and physical health of people, with long-lasting effects. The ophthalmic manifestations of COVID-19 ranged from follicular conjunctivitis to central retinal artery occlusion. Unusual symptoms like delirium and visual hallucinations, which were previously uncommon after any respiratory disease, have also been documented. We report five patients with COVID-19 disease who presented with peculiar visual symptoms and give a brief overview of the cases reported so far.
Case 1
A 33-year-old female physician complained of seeing rain-like floaters in both eyes for 10 days. She also reported palinopsia; that is, she continued to see the image of the object even after she stopped looking at it. She was otherwise healthy, with no prior physical or mental health problems and no history of recreational drug use. She suffered from mild COVID-19 illness twice, ten months apart, with the second episode happening 4 months before presenting. The diagnosis was confirmed by RT-PCR.
One month later, she developed a migraine attack with transient blurring of vision and headache. Two months after that, she had a second migraine attack accompanied by numbness of her tongue and the left side of her body for one day. Extensive investigation, including routine hemogram, coagulation work-up, dDimer, vasculitis work-up, autoimmune work-up, liver function tests, serum homocysteine, vitamin B12, Vitamin D, MRI of the brain, and MRA, were all normal, and her evaluation was negative for any neurologic disorders. Her ophthalmic evaluation was also normal, with 20/20 vision, normal anterior and posterior segments, intraocular pressures, color vision, and perimetry.
She was diagnosed with visual snow syndrome. She was prescribed dark brown tinted glasses with 20% transmission (Sunny green ET12 by Essilor), which she felt reduced the visual snow floaters a little when reviewed two months later.
Case 2
A healthy, 10-year-old boy presented with complaints of seeing grains in front of his eyes, with shakiness of field and smudgy images for two months. The symptoms were more apparent in dim light. There was no history of headaches, migraine, or blackouts. He had mild COVID-19 disease one year ago. His unaided vision was 20/20. His extraocular movements, orthoptic work-up, anterior segment evaluation, retinal examination, OCT, and perimetry were normal, and his neurologic evaluation was also normal.
He was diagnosed with visual snow syndrome and was prescribed tinted glasses (Sunny green ET12 by Essilor, with 20% transmission). His parents were informed about the benign nature of the condition.
Case 3
A 42-year-old male physician complained of loss of balance and dizziness with loss of orientation while going into bright light from dim light. He reported seeing bright smudgy shadows adjacent to objects, more in bright light, associated with lightheadedness. These symptoms had been persistent for the last ten months, having appeared two months after a conservative COVID-19 infection ten months prior. He had no trouble adapting from bright light to dim light. He was a known diabetic under treatment for nine years with an HbA1c level of 7.5%. History for migraine and any neurological issue was negative.
His vision was 20/20, and his complete ophthalmic evaluation was normal. He had consulted a neurologist and otorhinolaryngologist, who detected no abnormalities. He underwent a complete optometric evaluation but did not find any difference with the tinted glasses. No medical treatment was offered, and the patient preferred to observe the condition further.
Case 4
A 54-year-old female complained of seeing insects flying and raindrops falling in both eyes for the last eight months. She had a mild COVID-19 two years prior, which required only home isolation. She did not have migraine or any neurologic or psychologic problems. She had been diagnosed with sectoral retinitis pigmentosa (RP) in the past.
Her unaided vision was 20/30 and N6. Retinal examination showed symmetric bone spicule pigmentation in the inferonasal quadrant, and OCT revealed normal maculae. Reduced photopic and scotopic responses on electroretinography and a superior field defect confirmed the sectoral RP. There was no change in her visual system. She was evaluated by a neurologist and was found to have no neurologic problem. She was a homemaker and did not want any tinted glasses. The neurologist deferred any medical treatment as the neurologic evaluation was normal.
Case 5
A 43-year-old male software engineer complained of excessive glare for six months. He had a mild COVID-19 disease one year ago. He complained of sensitivity to light and feeling dizzy in bright light. He had -17.00 D refractive error in the left eye and had undergone scleral buckling surgery for retinal detachment (RD) 24 years ago. The right eye had lost light perception in childhood following complications of dislocated cataract and RD. His vision in the left eye was 20/20 with a soft contact lens. The retina was well attached. His neurologic evaluation was normal. His symptoms persisted for the next ten months until his last visit. No treatment was offered to him except for observation as the symptoms were not relieved with any of the optometric measures tried.