Table 2.

Ocular manifestations associated with COVID-19 studies

Study no.	Author	Study purpose	Country	Design	N	Age (years),mean±SD(range)	Patients with positive RT-PCR, n (%)/sampling technique	Findings
9	Chen et al.33	To investigate the ocular manifestations and clinical characteristics of COVID-19 patients	China	Cross-sectional	534	Median 44 (range 28.5–54.2)	342 (64.4)/nasopharyngeal swabs	A total of 25 (4.68%) presented with conjunctival congestion. A total of 3 (0.005%) had conjunctival congestion as the initial symptom. A total of 332 (62%) had eye–hand contact history
10	Ceran et al.34	To describe the ocular manifestations and investigate the association between ocular involvement and clinical presentation and laboratory outcomes in COVID-19 patients	Turkey	Cross-sectional	93	39.4±21.9	92 (99)/nasopharyngeal swabs, 1 (1.1)/endotracheal aspirate	A total of 20 patients (21.5%) had at least one ocular abnormality. A total of 2 (0.02%) had ocular manifestations consistent with conjunctivitis (hyperaemia, epiphora, increased secretion, chemosis, follicular conjunctivitis, episcleritis)
3*	Seah et al.17	To determine the possibility of transmission through tears by assessing for the presence of SARS-CoV-2 with viral isolation and quantitative RT-PCR analysis	Singapore	Prospective	17	N/A	17 (100)/nasopharyngeal swabs and tear samples using the Schirmer test	None demonstrated ocular symptoms
4*	Xia et al.29	To assess the presence of novel coronavirus in tears and conjunctival secretions of SARS-CoV-2-infected patients	China	Prospective	30	54.50±14.17	55 (91.6)/sputum samples (were taken twice), 1 (3)/tears and conjunctival secretions swab	One case (3%) had a positive SARS-CoV-2 result in the tears and conjunctival secretions samples. Notably, that was the only case presented with conjunctivitis
7*	Wu et al.32	To investigate ocular manifestations and viral prevalence in the conjunctiva of patients with COVID-19	China	Retrospective	38	Median 68 (interquartile range 53–76)	28 (73.7)/ nasopharyngeal swabs, 2 (5)/conjunctival swabs	A total of 12 cases (32%) had ocular manifestations consistent with conjunctivitis
11	Mungmung-puntipantip and Wiwanitki35	To detect ocular manifestations in COVID-19 patients	Thailand	N/A	48	N/A	N/A (direct ophthalmoscopy and corneal scraping for suspected conjunctivitis case)	None demonstrated ocular symptoms
1*	Zhou et al.27	To investigate the possible transmission of 2019-nCoV through aerosol contact with the conjunctiva	China	Retrospective cohort	67	35.7±10.6	63 (94)/nasopharyngeal swabs	One case (0.14%) of conjunctivitis as the initial symptom
12	Valente et al.36	To evaluate ocular manifestations prevalence in the tears of children with COVID-19	Italy	Prospective observational case series study	27	Range 1–216 months	20 (74)/nasopharyngeal swabs, 3 (11)/conjunctival swabs	A total of 4 (15%) had ocular manifestations consistent with viral conjunctivitis
6*	Sun et al.31	To identify whether SARS-CoV-2 infected the ocular surface	China	Cross-sectional	102	57.63±14.90	72 (70.6)/nasopharyngeal swabs, 1 (0.98)/conjunctival swab	A total of 2 (0.019%) had ocular manifestations consistent with conjunctivitis. However, fragments of the SARS-CoV-2 were found in ocular secretions in one of these two patients
13	Hong et al.37	To evaluate ocular symptoms and ocular tropism of SARS-CoV‐2 in patients with COVID-19	China	NA	56	48±12.1	1 (1.7)/conjunctival swab	A total of 15 (27%) had aggravated ocular symptoms, 2 of which had conjunctivitis. Only one of these two patients had a positive conjunctival swab
14	Colavita et al.38	To present the early detection of infectious SARS-CoV-2 in ocular fluids from a patient with the first confirmed case of COVID-19 in Italy	Italy	Case report	1	65	Sputum sample and ocular swab	Positive ocular swab detected 3 d from SARS-CoV-2 symptoms onset to 9 days (severe conjunctivitis)
15	Cheema et al.39	To present a case of COVID-19 disease with an initial medical presentation of keratoconjunctivitis, the first such reported case in North America	Canada	Case report	1	29	Nasopharyngeal swab and conjunctival swab	Keratoconjunctivitis. Weakly positive eye swab taken 4 d after conjunctivitis onset
16	Chen et al.40	To report the ocular characteristics and the presence of viral RNA of severe SARS-CoV-2 in the conjunctival swab of a COVID-19 patient	China	Case report	1	30	Nasopharyngeal swab and conjunctival swab	The conjunctival swab was positive for COVID-19 on 14 and 17 d after onset

*The same patients were analysed separately for transmission (Table1) and manifestations (Table 2).