There have been several individual case reports and small-scale studies performed which documented ophthalmic involvement of COVID-19. Many of the reported ocular symptoms are summarized in Table 1, which highlights adult cases. It includes the study design, number of subjects, age of subjects, and reverse transcription polymerase chain reaction (RT-PCR) results for presence of SARS-CoV-2 in nasal and lacrimal secretions. It also has symptom presentation and day of onset if available, along with treatment regimen used for that case. If the patient presented to the provider with an ocular manifestation, this was noted as an initial finding, unless it was otherwise specified. Geographic location, age distribution, or general COVID-19 presentation may be contributing factors and there are inadequate numbers of studies at this time to suggest any definitive findings.
In larger-scale studies, ocular findings may not be documented because the focus of most studies has been on the lung, cardiac, or gastroenterological effects of the virus. Therefore, the majority of the ocular findings have come from individual case reports. In the following paragraphs, we highlight several case reports that describe ocular findings as part of the early presentation of COVID-19.
One traveler from Wuhan to Italy developed bilateral conjunctivitis initially as part of her viral prodrome and ocular swabs were collected daily beginning on day 3. The swabs were positive for SARS-CoV-2 RNA throughout the entire disease course. By day 20, the conjunctivitis disappeared, but positive swabs were collected at day 27, even after nasopharyngeal swabs had become negative .
Another traveler returning from the Philippines presented with unilateral keratoconjunctivitis and photophobia that was presumed to be herpetic in nature, given the presence of one small pseudodendrite on exam. Despite antibacterial and antiviral treatment, the erythema and irritation worsened, and vision began to decline. An ocular swab taken for gonorrhea and chlamydia was retrospectively tested for SARS-CoV-2 and was weakly positive .
A telemedicine report from Argentina identified a patient with a chief complaint of foreign body sensation and redness of the left eye with no other systemic symptoms. On exam, unilateral eyelid edema and moderate conjunctival hyperemia were found. Three hours later, this patient developed a high fever with severe headache, and 12 h later developed cough and severe dyspnea. The patient tested positive for SARS-CoV-2 on nasopharyngeal swab. Ocular symptoms resolved at day 11 of his disease course .
In a similar case, a patient presented with burning eye pain with a discharge for 2 days. On slit lamp exam, mucoid discharge and follicular conjunctivitis were seen. The individual was diagnosed with viral conjunctivitis and treated with artificial tears. Two days later, he went to the emergency department with sudden onset of fever, cough, and shortness of breath and was found to be COVID-19 positive .
Another case report described a confirmed positive COVID-19 cruise ship traveler who had bilateral conjunctivitis, characterized by irritation, photophobia, and watery secretions, as his only symptom during the entire disease course .
These case studies support the importance of conjunctivitis as an early presenting symptom and COVID-19 should be considered in the differential diagnosis of conjunctivitis . A few larger-scale studies have also been reported.
Siedlecki et al. reviewed 21 articles on ocular findings in COVID-19 and discussed findings from each study. Ocular findings included conjunctival hyperemia, chemosis, inferior palpebral conjunctival follicles, lid swelling, and keratitis with subepithelial infiltrates and overlying epithelial defects. The timing of presentation was also variable, some with conjunctivitis as an initial presentation and some developing it later in the disease course .
Zhou et al. performed a retrospective cohort study which had 63 confirmed COVID-positive patients. Only one of the patients had conjunctivitis and this individual was not positive by RT-PCR for SARS-CoV-2 on conjunctival swab. However, three others who did not have ocular symptoms showed positive viral detection on conjunctival swabs .
Sun et al. performed a cross-sectional study at Tongji Hospital in China which had 72 confirmed COVID-positive individuals. Of these, two individuals presented with conjunctivitis. Interestingly, only one out of the two individuals with conjunctivitis had positive RT-PCR on a conjunctival swab .
Xia et al. presented a prospective interventional case series on 30 coronavirus patients with pneumonia in which two ocular swabs were tested for SARS-CoV-2 on RT-PCR for each patient. One individual had conjunctivitis as a symptom along with positive viral detection on both swabs, while the swabs from the remaining 29 patients were all negative .
Finally, Atum et al. presented a study which tested RT-PCR positivity on nasopharyngeal and conjunctival samples for 40 patients. Ten of the subjects had conjunctivitis on exam, and one of these 10 subjects had a positive conjunctival swab for SARS-CoV-2. A total of three patients had positive conjunctival swabs .
In Table 1, we emphasize when in the course of COVID-19 the ocular symptoms were experienced, and indeed there are cases in which it does not present initially. For example, Lomi et al. conducted a retrospective study in India which included 127 subjects. Eleven patients reported ocular symptoms. Of these, six developed symptoms later in the course with other systemic findings, while five had ocular manifestation as the primary COVID-related finding . Furthermore, Chen et al. described a 30-year-old individual in Shenzhen, China who developed foreign body sensation, along with bilateral erythema and tearing 13 days following the onset of systemic COVID-19 symptoms. His conjunctival swab remained positive for SARS-CoV-2 on RT-PCR testing from day 13 to 17. Slit lamp exam of this patient showed findings that were consistent with acute viral conjunctivitis including bilateral moderate conjunctival hyperemia, watery discharge, inferior palpebral conjunctival follicles, and tender palpable preauricular lymph nodes . Guo et al. described a 53-year-old-man who developed unilateral conjunctivitis 10 days after the onset of symptoms at which time RT-PCR testing of conjunctival secretion was positive for the virus. Interestingly, the patient’s symptoms resolved with levofloxacin drops, but returned as bilateral keratoconjunctivitis 5 days later, this time with negative PCR testing . However, the vast majority of studies placed ocular manifestation as early in the disease course, apparent on Fig. 1 which organizes all ocular findings by age and day of symptom onset.