Table 1.
Characteristics of studies included in the systematic review.
| Study Name | Country | Publication Date | Sample Size Study Design Age (Media ± SD) Gender |
Visual Impairment Description | “Laterality” | Visual Acuity | Duration between the Onset of COVID-19 Symptoms and Ocular Symptoms | Comorbidities | Patients with COVID-19 (N and %) | Diagnosis |
|---|---|---|---|---|---|---|---|---|---|---|
| Kaya et al. [11] | Turkey | 28 April 2020 | N = 1 Case report 38 Male |
Vision loss in both eyes | Bilateral | OU: perception light | 5 days | NA | 1 | PRES |
| Selvaraj et al. [8] |
USA | 10 June 2020 | N = 1 Case Report 50 Female |
Acute, painless RE monocular visual disturbance, described as a white cloud and blurriness involving most of her RE, sparing the superior nasal aspect. | Monocular | RE: 20/70 | 7 days | NA | 1 | PION |
| Reich et al. [35] | Germany | 17 August 2020 | N = 1 each case Case sries Case 1: 64 Case 2: 43 Case 3: 60 Case 1: Female Case 2 and 3: Male |
Immediately after regaining full consciousness, the patients reported visual impairment. | Case 1 and 3: Bilateral Case 2: Monolateral |
Case 1: OU: 0.5 LogMar Case 2: LE: 1 LogMar Case 3: RE: light perception LE: 1.0 LogMar |
Soon after extubation (after 7–16 days of mechanical ventilation) | Case 1: obesity Case 2: arterial hypertension and medical history of carbon monoxide poisoning Case 3: arterial hypertension, insulin-dependent diabetes mellitus, grade 1 obesity, and nicotine abuse |
1 each case | Case 1: Optic Atrophy Case 2: High Intraocular Pressure (IOP > 50) Case 3: Optic Atrophy |
| Cyr et al. [26] | USA | September 2020 | N = 1 each case Case series Patient 1: 61 Patient 2: 34 patient 1: male patient 2: Female |
Patient 1: sudden, painless loss of vision for 2 days Patient 2: sudden, painless loss of vision of two-day duration. |
Patient 1: bilateral Patient 2: bilateral |
Patient 1: light perception Patient 2: light perception |
Patient 1: 7 days Patient 2: 10 days |
Patient 1: non–insulin-dependent diabetes mellitus Patient 2: four systemic lupus erythematosus, hypertension, end-stage renal disease on hemodialysis, chronic obstructive pulmonary disease |
1 each case | Patient 1: acute bilateral occipital territorial ischemic infarct Patient 2: acute infarct in the right frontal lobe, acute left posterior temporal-occipital territorial infarction and bilateral medial occipital |
| Zhou et al. [29] | USA | September 2020 | N = 1 Case report 26 Male |
Bilateral, subacute, sequential vision loss first affecting the LE, then the RE 3 days later | Bilateral | RE: HM LE: 20/250 |
“Few days” | None | 1 | Severe optic neuritis and myelitis |
| Benito Pascual et al. [21] | Spain | 1 September 2020 | N = 1 Case Report 60 Female |
Ocular pain, blurred vision, and redness in her LE | Monolateral | LE: 20/200 | 14 days | NA | 1 | Panuveitis and Optic Neuritis |
| Khan et al. [19] | Pakistan | 3 September 2020 | N = 1 Case report 60 Male |
Bilateral visual loss | Bilateral | NA | 24 h | NA | 1 | Cortical blindness secondary to occipital lobe stroke |
| Invernizzi et al. [30] | Italy | 25 September 2020 | N = 1 Case report 54 Female |
Scotomas and decreased vision in her RE | Monolateral | RE: 20/40 | 10 days | NA | 1 | Impending Central Retinal Vein Occlusion |
| Gascon et al. [17] | France | 06 Oct 2020 | N = 1 Case Report 50 Male |
LE: negative scotoma and acute onset of dyschromatopsia and decreased visual acuity | Monolateral | LE: 20/63 | 8 days | Splenectomy and RE: Glaucoma | 1 | Acute macular neuroretinopathy and paracentral acute middle maculopathy |
| Catharino et al. [22] | Brazil | 18 November 2020 | N = 1 Case Report 64 Male |
NA | Monolateral | NA | The same day | hypertension | 1 | Optic Neuritis |
| Murchison et al. [34] | USA | 15 December 2020 | N = 1 Case Report “Fifth decade” Male |
RE: Acute onset of painless visual loss | Monolateral | RE: HM | 3-weeks | Hypertension, tobacco use, and occasional marijuana use | 1 | CRAO |
| Francois et al. [36] | France | 17 December 2020 | N = 1 Case Report “Late 50 s” Female |
Blurred vision and redness in her RE and temporary (eight-day history) pain when mobilizing the globe |
Monolateral | RE: HM | 2 days | NA | 1 | Ocular neuropathy and panuveitis |
| Elhassan 2021 [15] | UK | 19 January 2021 | N = 1 Case Report 52 Female |
Complete cortical blindness with poor insight into the extent of her visual impairment, often claiming to be able to see (Anton’s syndrome) and hallucinations | Bilateral | No perception light | 31 | None | 1 | PRES |
| Liu et al. [20] | China | 03 February 2021 | N = 1 Case Report 66 Female |
“Shadows similar to cotton wool” with her LE followed by monocular blindness |
Monolateral | No light perception | First symptoms 10 days after COVID-19, blindness after 3 weeks from initial symptoms | None | 1 | Acute viral retinitis, optic neuritis, uveitis and secondary glaucoma |
| De Souza et al. [28] | Brazil | 19 February 2021 | N = 1 Case Report 23 Male |
Acute painless loss of central vision in his RE | Monolateral | RE: 20/800 | NA | NA | 1 | Multifocal choroiditis |
| Katti et al. [10] | India | 16 March 2021 | N = 1 Case Report 66 Male |
Sudden bilateral loss of vision | Bilateral | RE/LE: no light perception | 10 days | None | 1 | Pituitary macroadenoma with apoplexy and stroke |
| Rodríguez-Rodríguez et al. [13] | Mexico | 23 March 2021 | N = 1 Case Report 55 Female |
Unilateral, gradual visual loss, decreasing visual acuity, and chromatic impairment | Bilateral | RE: 20/40 LE: 20/200 |
NA | None | 1 | Optic neuritis |
| Veisi et al. [14] | Iran | 10 April 2021 | N = 1 each case Case Series Case 1: 40 Case 2: 54 Case 1: Female Case 2: Male |
Case 1: bilateral visual loss and complete ophthalmoplegia of the RE Case 2: vision loss, proptosis, orbital inflammation, and complete ophthalmoplegia on the left side |
Case 1: bilateral Case 2: monolateral |
Case 1: no light perception Case 2: LE light percepetion |
Case 1: 15 days Case 2: 7 days |
Case 1 None Case 2 Non-insulin-dependent diabetes mellitus |
1 per case | Case 1: Mucormycosis Case 2: Rhino-orbital mucormycosis |
| Carcamo Garcia et al. [23] | Perù | 14 April 2021 | N = 199 Cross-sectional study 42.8 ±15.1 85 males and 114 females |
Visual changes 24 (12%): Visual symptoms: 23 (11.6%) Unilateral 0 (0%) Bilateral 15 (65.2%) Deficient color vision 4 (17.4%) Vision loss 17 (73.9%) Double vision 3 (13%) |
NA | NA | 8 ± 6 days | Hypercholesterolemia (12%), followed by hypertension (10%), prior history of tuberculosis or other pulmonary disease (9%) and diabetes (7%), cancer (4%); chronic kidney disease (2%) cerebrovascular disease or stroke (1%). Nearly 10% of the cohort had a history of smoking or were current smokers. | 199 |
Bilateral visual changes and decreased visual acuity were the most common symptoms in patients with mild-moderate COVID-19 infection. |
| Crane et al. [25] | USA | 21 April 2021 | N = 1 Case Report 35 Male |
Vision loss with no associated pain or redness started in the LE but very quickly involving the RE |
Bilateral | RE/LE: Light perception | NA | diabetes, cirrhosis | 1 | Endogenous Klebsiella endophthalmitis. |
| Deane et al. [31] | USA | 13 June 2021 | N = 1 Case Report 21 Female |
Blurry vision in her LE associated with one-week history of severe headaches with pain with movements in all directions in her LE | Monolateral | LE: Hand Motion | NA | NA | 1 | Optic Neuritis |
| Eswaran et al. [27] | India | 13 June 2021 | N = 1 Case Report 31 Male |
Bilateral proptosis, loss of vision and ophthalmoplegia | Bilateral | NA | NA | Diabetes | 1 | Mucormycosis |
| Clarke et al. [24] | UK | 13 July 2021 | N = 1 Case Report 55 Male |
Profound bilateral vision loss after cessation of sedation | Bilateral | LE: 3/30 unaided RE: counting fingers | NA | Hypercholesterolemia and hypertension | 1 | NAION due to Prone Position |
| Gonzalez et al. [16] | USA | 19 July 2021 | N = 1 Case Report 32 Female |
Sudden vision loss in her LE, associated with a one-week history of pain, redness, and photophobia |
Monocular | LE: perception light | 24 h | Left retinal detachment secondary to necrotizing herpetic retinitis | 1 | Acute retinal necrosis |
| Atum et al. [12] | Turkey | 23 July 2021 | N = 1 Case Report 84 Male |
Sudden vision loss | Bilateral | HM | 5 days | NA | 1 | Bilateral occipital ischemic stroke |
| Micieli et al. [33] | Canada | 29 July 2021 | N = 1 Case Report 31 Male |
RE vision loss after 10-day history of pain that worsened with eye movements and blurred vision | Monolateral | RE: CF at 4 feet | 12 | None | 1 | Optic Neuritis |
| Eslamiyeh et al. [18] | Iran | 8 August 2021 | N = 1 Case Report 8 Male |
Sudden bilateral and progressive blurring of vision in the RE | Bilateral | RE: 2/10 LE: 4/10 | NA | NA | 1 | Optic Neuritis |
| Malek et al. [32] | Tunisie | 18 October 2021 | N = 1 Case Report 20 Male |
Rapid bilateral visual loss with left periorbital pain, proptosis, palpebral edema, and swelling | Bilateral | No LP | 7 days | NA | 1 | Rhino-orbito-cerebral mucormycosis, left cavernous sinus and internal carotid thrombosis together with a right CRAO |
| Mani et al. [9] | India | 25 February 2022 | N = 89 Cross-sectional study 54.71 ± 11.03 70 males and 19 females |
ROCM (stage 3c): 1 patient: Bilateral orbital involvement with loss of vision ROCM (stage 3d) 35 patients: central retinal artery occlusion or involvement of orbital apex, superior orbital fissure, inferior orbital fissure with loss of vision |
One patient bilateral, 35 patients monolateral | NA | NA | Diabetes | 89 | Rhino-orbital-cerebral mucormycosis |
Abbreviations: NA: not applicable; ROMC: rhino-orbital-mucormycosis; CRAO: central retinal artery occlusion; RE: right eye; LE: left eye; OU: oculus uterque; N: number; CF: counter fingers; HM: hand motions; USA: United States of America, UK: United Kingdom; NAION: non-arteritic anterior ischemic optic neuropathy; PCR: polimerase chain reaction; IOP: Intraocular pressure, PION: posterior ischemic optic neuropathy; PRES: posterior reversible encephalopathy syndrome.