Table 2. Study design and clinical characteristics of cases with SARS-CoV-2 detected on the ocular surface in previous studies.
| Reference | Sample size, persons | Ocular sample collection | Days from onset to first ocular sampling | Detection method | Positive rate | Clinical characteristics of positive cases | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| Demographic and epidemiological characteristics | General symptoms | Ocular symptoms | Ocular sampling results | Temperature when PCR was positive, °C | ||||||
| Xia et al. (4) | 30 (21 common/9 severe)* | Conjunctival swabs | 7.33±3.82; range: 1–16 | RT-PCR | 1/30 | 53-year-old male; common type* | NA | Conjunctivitis | Day# 3 and 5: all + | Day# 3: 36.2; day# 5: 36.5 |
| Deng et al. (5) | 114 (19 moderate/59 severe/36 critical) | Conjunctival swabs | NA | RT-PCR | 0 | NA | NA | NA | NA | NA |
| Zhou et al. (6) | 121 | Conjunctival swabs | 15.0±8.8 | RT-PCR | +: 3/121 ±: 4/121 | Severe or critical type | NA | Yes | + | NA |
| Severe or critical type | NA | No | + | NA | ||||||
| Mild or moderate type | NA | No | + | NA | ||||||
| Zhang et al. (7) | 102 | Conjunctival swabs | 18.15±7.57; range: 6–46 | RT-PCR | 1/102 | 29-year-old female; nurse; worked with N95 respirators but a dislocated eye mask touching eyelids sometimes | Fever (day 1, 2, 4 and 10), cough (day 4 to 21) | Conjunctival congestion and watery discharges in both eyes (day 2 to 5) | Day# 3: +; day# 10, 19, 21: − | 36.5 |
| Seah et al. (8) | 17 | Schirmer’s strip tear collection | 11.00±5.09; range: 3–20 | RT-PCR and viral isolation | 0 | NA | NA | NA | NA | NA |
| Wu et al. (9) | 38 | Conjunctival swabs | NA | RT-PCR | 1/19 | 50-year-old male; critical type | Cough, expectorate | Conjunctival congestion, secretion | + | 39.9 |
| 60-year-old female; critical type | Cough | Chemosis, epiphora | + | 36.8 | ||||||
| Xie et al. (10) | 33 | Conjunctival swabs | Within 1 week after diagnosis | RT-PCR | 2/33 | 90-year-old female; died of multiple organ failure 8 days after onset | Fever, headache, dyspnea | No | Day# 5: + | NA |
| 48-year-old male | Fever, cough | No | Day# 4: + | NA | ||||||
| Dutescu et al. (11) | 18 (5 critical) | Tear samples obtained with a lab capillary | NA | RT-PCR | 5/18 | NA | NA | NA | + | NA |
#, day after symptom onset. *, severe type diagnostic criteria were: (I) respiratory distress (respiratory rate≥30 cycles/min), (II) oxygen saturation ≤93% or arterial partial pressure of oxygen (PaO2)/oxygen concentration FiO2 ≤300 mmHg in the resting state, (III) respiratory failure requiring mechanical ventilation, (IV) shock, and (V) other forms of organ failure requiring monitoring and treatment at the intensive care unit. Common type was defined as diagnosed patients excluding the severe-type criteria. +: positive; ±: probable positive; −: negative. SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; NA, not available; CBC, complete blood count; COPD, chronic obstructive pulmonary disease; CT, computed tomography; WBC, white blood cells.