Table 1.

Details of all cases of NO

The authors of the study	Age/ sex	Duration between positive PCR Covid test and ocular symptoms (weeks)	Covid 19 form and comorbidities	Ocular signs and symptoms	Diagnosis	Evolution and treatment
Szydełko-Paśko U et al. [2]	69/ F	2,5 weeks	Mild form; without hospitalization, just fever, cough, fatigue. Comorbidities: HT, well-controlled type II DM	BCVA RE = 0.9; BCVA LE = nasal and superior LP, without APD in RE; LE: pupil is reactive to direct light, slowly reactive to indirect light; IOP in RE = 10 mmHg, IOP in LE = 09 mmHg. BM: Cortical cataract RE; Fundus RE: cotton wool spots in the upper arterio-venous sector. Fundus LE: blurring of the optic margins with flame hemorrhages; AFG: delayed choroidal filling with watershed areas	LE: AAION in the course of giant cell arteritis after Covid 19	Enoxaparin 0.4 ml/ day for 10 days then PDN 80 mg/ day for 4 days. At discharge: MTX 15 mg/ week and PDN with tapering doses. At 3 months: BCVA RE = 0.8, BCVA LE = LP; OCT: macular traction, RE: normal optic disc, LE: thinning RNFL with optic atrophy.
Kitson D et al. [3]	21/ F	1 week	Mild form; ocular onset with accidental discovery of PCR +	BCVA RE = 20/ 20, BCVA LE = HM. IOP-RE = 21 mmHg, IOP-LE = 23 mmHg; Fundus RE: mild temporal burring of papilla with nasal sparing; Fundus LE: papilledema	LE: Unilateral ON associated with Sars-Cov-2 infection	MTPN, remdesivir and oral steroid at discharge. VA returned to normal after 5 days of treatment; after one month: normal VF and eye fundus.
Sawalha K et al. [4]	44/ M	2 weeks	Mild form; shortness of breath and cough, ambulatory symptomatic treatment	Bilateral eye pain, decrease of VA in both eyes 7 days before presentation to the ophthalmologist. BCVA RE = 20/ 200 with RAPD and global loss of VF; BCVA LE = 20/ 30 and superior arciform deficit of VF	Acute bilateral ON induced by Covid19	MTPN 1 g/ day for 5 days, then PDN 1 mg/ kg/ day for 11 days and another 4 days with tapering doses. After 48 hours: improved VA and pain relieved.
Saray Rodriguez M [5]	55/ F	2 weeks	Mild form; without respiratory symptoms	Exacerbated headache and eye pain when moving the eyeball in LE for approximately 12 days, despite NSAID treatment; gradual decrease in VA and chromatic impairment. BCVA RE = 20/ 40; BCVA LE = 20/ 200 with RAPD; RE: normal OCT; normal VF; LE-VF: inferior centrocecal and centronasal scotoma.	LE: ON after infection with Sars Cov 2	Oxygen therapy 1 g/ day, MTPN iv for 5 days, then oral PDN with tapering doses. After one month: BCVA RE = 20/ 40, BCVA LE = 20/ 400 with RAPD. Fundus LE: optic disc pallor; VF - centrocecal scotoma; OCT: RNFL thinning in the temporal sector and CGL decrease; MRI of the orbit: mild increased thickness and signal in the left optic nerve. Normal brain MRI, normal inflammatory tests, negative PCR. CSF exam: IgG oligoclonal bands present in CSF but not in serum, anti-AQP4 antibodies negative in CSF and serum. After one month: LE: without eye pain; optic atrophy despite the treatment.
Žorić L et al. [6]	63/ M	4 weeks	Moderate form; fatigue, shortness of breath, fever 38 degrees, dry cough, bilateral bronchopneumonia with PCR “ – ” but IgM and IgG antibodies for Covid+; SpO2=92%; hospitalized for antibiotic and anticoagulant treatment (due to increased suspicion of Covid) Comorbidities: HT and DM (new case)	BCVA RE = 0.03: BCVA LE = 1; Fundus RE: small papilledema; predominantly right-sided headache, therefore, suspicion of AAION. OCT: partial swelling of the optic nerve head and CGL; RAPD.	RE: ON in a patient with MOG+ antibodies during the post-COVID-19	MTPN 1 g/ day iv for 5 days and PDN for 2 weeks after hospitalization. Day 5: BCVA RE = 0.3; improved VF; no headache. Brain MRI on day 7 with contrast: signs of microangiopathy and cortical reduction, normal orbits and optic nerves. After 3 weeks, the antigenic bands for IgG and IgM were negative, without neurological signs. BCVA RE = 20/ 25 (0.8), without papillary edema; BCVA LE: normal. After 2 weeks: MOG + (titer 1:40), cut off 1:10. After 3 months: BCVA RE = 20/ 20; normal VF; VEP: slight prolonged latency of the p100 wave; OCT: thinning of the RNFL and CGL. Titer of MOG antibodies was 1:20 and titer of IgM and IgG atc for Sars Cov 2 were 17.32, respectively 40.02.
Jossy A et al. [7]	16/ M	2 weeks	Mild form; isolation at home, without oxygen therapy or steroids.	Sudden loss of vision in LE 3 days before, accompanied by headache and pain when moving the left eyeball. BCVA RE = 20/ 20cc, BCVA LE = LP with RAPD; both eye fundus- normal, without edema or hyperemia	LE: Retrobulbar ON	ONTT scheme: MTPN iv for 3 days, oral PDN 1 mg/ kg for 3 days, with tapering doses over the next 3 days. Day 7: BCVA LE = 20/ 120; day 21: BCVA LE = 20/ 60; after 2 months: BCVA LE = 20/ 32.
Jossy A et al. [7]	35/ M	6 months before vision loss	Mild form; isolation at home, without oxygen therapy or steroids.	Sudden loss of vision in LE, accompanied by pain when moving the eyeball for 7 days. BCVA RE = 20/ 20, BCVA LE = 20/ 600 with mild APD in LE. Fundus LE- papillary and peripapillary edema, also confirmed on OCT; normal RE fundus.	LE: Papillitis	ONTT scheme: MTPN iv 1 g/ day for 3 days, followed by oral PDN with tapering doses. After 2 weeks: BCVA LE = 20/ 200 without any change in the following 2 months.
Jossy A et al. [7]	38/ M	6 weeks	Mild form; isolation at home, without oxygen therapy or steroids.	Sudden loss of vision in LE, pain when moving the eyeball for 5 days. The patient presented the same symptomatology a month ago, for which he underwent iv treatment with MTPN and oral PDN. The symptoms improved after a week; after 3 weeks VA decreased again. Normal fundus, eyes fundus.	LE Retrobulbar ON associated with MOG+ antibodies	ONTT scheme: MTPN iv 1 g/ day for 3 days, followed by oral PDN with tapering doses. Day 7: BCVA LE = 20/ 20; without any change in the following 2 months.
Sarwar S et al. [8]	47/ F	3 weeks	Moderate form; hospitalized 3 weeks before for Covid with fever, dyspnea, cough, myalgia, oxygen therapy due to level fluctuations. Comorbidities: unbalanced DM type II	Blurring of vision in LE in the last 18 hours; mild pain behind the eyeball, exacerbated by movement of the eyeball; well-oriented in time and place, anxiety, afebrile, blood pressure 110/ 80 mmHg, heart rate: 92 beats/ minute, SpO2 97%. BCVA LE = 60/ 200, BCVA RE = 20/ 20; RAPD to LE; fundus LE: mild edema.	LE: ON associated with MS after Sars-Cov-2 infection	Prednisolone 1 g/ day and symptomatic treatment; upon discharge, tapering doses of oral dexamethasone with improvement of VA and general symptoms.
Azab MA et al. [9]	32/ M	2 weeks	Severe form, hospitalized for 10 days in ICU for severe complications, PCR+	One week later, the patient presented a gradual decrease in vision with a central scotoma in the LE; headaches. BCVA RE = 20/ 30, BCVA LE = 20/ 200, LE: RAPD; IOP RE = 16 mmHg, IOP LE = 23 mmHg, BM both eyes: normal; color depth affection; LE fundus: mild disc swelling, without other retinal changes.	LE: ON post COVID19 infection	Without antiviral treatment; paracetamol 1 g/ day for 7 days, then MTPN iv 1 g/ day for 3 days, then oral PDN 60 mg for 7 days with tapering doses. At the third visit: BCVA LE = 20/ 40; color depth affection.
Borrego- Sanz L et al. [10]	66/ F	When waking up after 40 days in ICU (6 weeks)	Severe form; ICU for severe respiratory failure for 40 days	BCVA RE = 0.9, BCVA LE = HM; OCT LE: marked optic nerve head pallor; large cupping, without hemorrhages or edema; narrowing of the arterioles, thickness of the peripapillary RNFL correlated with significant temporal defect of the VF; RAPD in the LE, normal RE fundus	LE: Optic neuropathy in a patient with COVID-19
Francois J et al. [11]	50/ F	2 days	Severe form, hospitalized for a severe bilateral pneumonia; she was suspected because of recent close contact with a fatal Covid 19 case	2 days after presentation: RE: blurring of vision accompanied by ocular congestion; temporal pain when moving the eyeball on day 8. BCVA RE = HM; BCVA LE = 0 logMar, RAPD; RE-VF: central scotoma, impaired color and contrast vision; BM RE: central nongranulomatous retrodescemetic precipitates and a mild inflammation in the anterior chamber. RE fundus-marked papillary edema, 2 peripapillary hemorrhages, mild vitreous inflammation, retinal vessel narrowing in the inferior retina.	RE: Optic neuropathy associated with panuveitis in COVID-19 infection	Local and general corticosteroids; Day 30: AFG-mild papillary edema and retinal vasculitis. After 1 month and a half: BCVA RE = + 2 log MAR (HM); normal anterior pole, without signs of inflammation, Fundus of RE: severe papillary atrophy.
Clarke KM et al. [12]	55/M	-	Severe form, fever 39.7 C0; blood pressure = 166/ 90 mmHg; respiratory frequency 40 beats/ minute; O2 was administered through nasal cannula, but it was not possible to maintain the saturation above 92% and therefore he was intubated and mechanically ventilated, taken to the ICU. Comorbidities: ex. smoker; HT; hypercholesterolemia.	After the cessation of the sedation, the patient had a profound, bilateral loss of vision, more pronounced at LE. Examination at bed BCVA RE = CF, BCVA LE = 3/ 30, IOP both eyes = 10 mmHg; relative APD in the RE. Fundus RE: papillary edema, splinter hemorrhages, which indicates sectorial NAION (infero-temporal); Fundus LE: mild papillary edema, temporal pallor, hemorrhages in the inferior sector. OCT both eyes - shortly after diagnosis - bilateral papillary edema, flame hemorrhages in the RE.	Both eyes - AION related to pronation in a patient with COVID-19 related ARDS	Mechanically ventilated in ICU, in pronation, with vasopressor medication, renal dialysis, blood transfusions. After 5 weeks: RE-VF: severe narrowing with preservation of macular vision; LE-VF: inferonasal loss with preservation of peripheral vision. After 2 months: OCT – both eyes: RNFL thinning with disc pallor. VA did not improve; the patient was advised to register to low vision support.
Golabchi N [13]	52/ M	2 weeks	Moderate form with fever, dyspnea, dry cough	7 days after discharge due to Covid: the sudden drop in VA in RE. BCVA RE = HM, BCVA LE = 9/ 10, normal BM exam; RE – RAPD Fundus of RE: pale disc, without edema, suggestive of a previous AION in antecedents; Fundus of LE: hyperemic optic disc. VF-RE: generalized depression with deep central and nasal scotoma, VF-LE: normal. OCT RE: diffuse thinning of the RNFL without macular edema.	RE – AION-a rare manifestation after COVID-19	Kaletra, Tamiflu, Hydroxychloroquine, Meropenem, Vancomycin, Tavanex. After 1 week: the patient is discharged with a good general condition, normal laboratory tests, no ocular complaints. After 4 weeks, irreversible optic atrophy in the RE.
Benito-Pascual B [14]	60/ F	-	-	LE: eye pain, conjunctival congestion and blurred vision. BCVA RE = 20/ 20; BCVA LE = 20/ 200; RAPD in LE. BM LE: panuveitis in AC with 3+, posterior synechiae. Fundus LE: vitritis 1+, papillary edema, subretinal fluid with peripapillary choroidal folds. OCT LE: RNFL edema.	LE- Panuveitis and ON as a possible initial presentation of Covid 19	Oral administration of PDN starting with a dose of 60 mg/ day; topical steroid every hour and mydriatics x 3/ day. Hydroxychloroquine 400 mg x 2/ day on day 1, then 200 mg/ day for 6 days; Kaletra 400 mg/ 100 mg x 2/ day for 10 days. After 15 days of hospitalization, at discharge: normal VA, anterior pole and eye fundus, without inflammatory signs; BCVA RE = 20/ 20, BCVA LE = 20/ 40. Fundus RE: C/ D 0.3, Fundus LE = C/ D 0.7 with pale optic disc; LE: VF defect. OCT LE: severe optic atrophy with RNFL and CGL thinning; PCR negative.
Assavapongpaiboon B, Jariyakosol S [15]	35/ F	1 week	Mild form, dry cough	Blurred vision and pain when moving the left eyeball. BCVA RE = 20/ 32; BCVA LE = CF; LE relative APD; Fundus both eyes-bilateral optic disc edema (LE > RE) CT scan of the brain and orbit: swollen optic nerve sheath; MOG + antibodies in serum.	Blurred vision and pain when moving the left eyeball. BCVA RE = 20/ 32; BCVA LE = CF; LE relative APD; Fundus both eyes-bilateral optic disc edema (LE > RE) CT scan of the brain and orbit: swollen optic nerve sheath; MOG + antibodies in serum.	MTPN 1 g/ day iv for 5 days, then oral prednisolone with slow tapering and oral Favipiravir for 5 days. 8 days after treatment: BCVA both eyes = 20/ 30; at 4 weeks: BCVA RE = 20/ 25; BCVA LE = 20/ 20 with a slight subjective residual dyschromatopsia in LE.
Sainath D [16]	56/ F	2 weeks	Mild form, fever, dry cough, isolation at home, treatment with vitamins	Both eyes- extraocular muscle movements – full but painful in superior and lateral gaze; BCVA = CF with alteration of the chromatic sense; BM and fundus of both eyes: normal; MRI of the brain and orbit: swelling of the right retrobulbar intraorbital segment of the optic nerve.	Acute bilateral retrobulbar ON - an atypical sequela of COVID-19	MTPN iv 250 mg x 4/ day for 3 days then oral MTPN 1 mg/ kg for 11 days according to ONTT After 7 days: BCVA both eyes = 6/ 9 (Snellen); VF both eyes: paracentral scotoma (30-2 Humpfrey) OCT LE RNFL normal thickness: 111 µm RE; 114 µm LE.
Sanoria A [17]	45/ M	4 weeks	Mild form, Comorbidities: well controlled DM II, HT	BCVA RE = 6/ 6; BCVA LE = 6/ 24; RAPD + to LE; Fundus RE: hyperemic papilla with blurred margins; Fundus of LE: pale, edematous papilla; OCT: increased RNFL (LE > RE); color vision and contrast sensitivity was reduced in LE. HumphreyVF central 30-2: inferior RE defect, inferior and superior LE defect; VEP: delayed latency of the P100 wave (120 ms RE, 225 ms LE) with reduced amplitude (6 µV RE, 1.7 µV LE); MRI brain and orbit: normal.	Bilateral sequential NAION post COVID-19	MTPN 1 mg/ kg for 6 days, then gradual, weekly dose reduction for 6 weeks. After one month of treatment: VF both eyes: persistent deficits; Fundus both eyes: disc pallor with gradual remission of edema.
Mahfuzullah MA [18]	45/ M	3 weeks	Mild form	BCVA RE = 3/ 60; BCVA LE = 6/ 6; RAPD in RE with impaired color vision; Fundus RE: papillary edema; Fundus LE – normal.	RE-ON post COVID-19	MTPN 1 g/ day for 3 days, then oral prednisolone; after treatment: BCVA RE = 6/ 9.
Mahfuzullah MA [18]	28/ F	4 weeks	Mild form	BCVA RE = 6/ 6; BCVA LE = 6/ 36; relative APD In LE with impaired color vision; Fundus LE: papillary edema in the nasal sector; Fundus RE - normal.	RE-ON post COVID-19	MTPN 1 g/ day for 3 days, then oral prednisolone; after treatment: BCVA RE = 6/ 9.
Mahfuzullah MA [18]	40/ F	8 weeks	Mild form, normal O2 saturation, fever, loss of taste and smell, without PCR	RE - blurring of vision for 15 days but without pain and congestion; BCVA RE = 3/ 6; relative APD in RE; impaired color vision; BCVA LE = 6/ 6; Fundus RE: papillary edema with star shaped macular exudate; fundus LE: normal.	RE-ON post COVID-19	MTPN 1 g/ day for 3 days, then oral prednisolone; after treatment: BCVA RE = 6/ 24.
BCVA RE = best correction visual acuity right eye, BCVA LE = best correction visual acuity left eye, LP = light perception, RAPD = relative afferent pupillary defect, BM = biomicroscopy; IOP = intraocular pressure, AFG = angiofluorography, AAION = arteritic anterior ischemic optic neuropathy, PDN = prednisone, MTX = methotrexate, MTPN = methylprednisolone, RNFL = retinal nerve fiber layer, OCT = optical coherence tomography, LP = light perception, HM = hand motion, NSAID = non-steroidal anti-inflammatory drugs, CGL = cells ganglion layer, MRI = magnetic resonance imaging, CSF = cerebrospinal fluid, AQP4 = anti aquaporin4, MOG = myelin oligodendrocyte glycoprotein, AION = anterior ischemic optic neuropathy, VEP = visual evoked potential, CF = counting fingers, DM = Diabetes mellitus, HT = Hypertension, ON = Optic neuritis, VF = visual field, ICU = intensive care unit, AC = anterior chamber, MS = multiple sclerosis