To the best of our knowledge, this is the first survey that evaluated the impact of exposure to screens during the COVID-19 lockdown on VKC clinical manifestations in a pediatric population.
The management of several diseases during home quarantine has changed and adapted to this critical period where the priority of the hospitals has been the management of emergencies. For this reason, the use of surveys has been useful to understand the impacts and consequences of home quarantine on signs and symptoms in several pathologies, as well as VKC.
VKC is not, like allergies, a risk factor for the susceptibility to SARS CoV- 2 infections, and neither is their treatment; for this reason, the standard treatment should be continued in VKC as well as in allergic pathologies [30,31,32]. VKC is a chronic inflammatory ocular pathology in which photophobia is one of the most troublesome clinical manifestations, together with foreign body sensation, itching and tearing that are also present in AC .
During the lockdown, there was a reduction in exposure to sunlight, but conversely, the time spent in front of PCs, TVs and video games increased . During the lockdown, long-distance learning has been instituted for children over the age of 5, using video-conference platforms. This had the drawback of exposing children and adolescents to a critical load of screen time. Indeed, some of our patients had to regularly sit in front of screens for 6 or more hours per day.
Establishing controlled exposure to screens allowed us to evaluate more accurately than before the effect of different loads of light exposure from screens on a subset of children, as VKC patients, for whom light is a trigger of clinical manifestations.
Consistent with this situation, results of our study have shown a general trend of worsening of VKC clinical manifestations, such as tearing, foreign body sensation and burning, when comparing the “2–4 h/day” group to the “more than 6 hours/day” group. The T-test analysis showed a statistically significant difference between the group with the minimum exposure compared to the group with the most exposure (“more than 6 hours of screen time/day”) to screens.
Instead, the symptom of itching was found to be stable between the 2–4 and 4-6 h/day groups and the symptom photophobia was apparently less severe in the “more than 6 hours/day” group when compared to the “4-6 h/day” group, but the statistical analysis found no statistical significance.
A strong Pearson correlation coefficient has shown a high correlation between screen exposure and all VKC symptoms, such as itching, photophobia, tearing, foreign body sensation, and burning.
Moreover, considering the comparison between 2020 and 2019 in the same period (March–June), only photophobia and foreign body sensation showed a decrease in 2020 in comparison with the previous year, with a statistically significant difference (T-test p-values respectively 0.006 and 0.004). In contrast, all other signs and symptoms were not found as significantly different.
When considering Rome and Florence separately, the statistical analysis revealed further information. Referring to Policlinico Umberto I Hospital, we found a statistically significant reduction in the severity of symptoms during home quarantine in 2020 compared to the same period of the previous year. Instead we have seen a mild worsening of VKC symptoms among patients from Meyer Children’s University Hospital during the lockdown period in 2020 compared to the same period of 2019, but with poor statistical significance: only for the clinical manifestation of burning the difference between 2020 versus 2019 reached statistical significance.
These results could be explained by the different weather and latitudes of the two centers. Sunlight exposure is more abundant in southern regions, so patients referring to Policlinico Umberto I probably experienced a relative reduction of light exposure during the lockdown compared to the previous year, even considering the “Mandatory” screen light exposure required by long-distance learning. This might have played a role in the reported improvement in signs and symptoms by children referring to this center. In northern regions, sunlight is less abundant, so the reduction in sunlight exposure is relatively less significant when compared to the increase in screen exposure, resulting in a slight worsening of VKC signs and symptoms. To the best of our knowledge, no studies regarding the specific influence of latitude on VKC symptoms have been carried out yet.
In literature, several studies have been conducted considering allergic pathologies and in particular allergic conjunctivitis during lockdown [1, 31, 34], but to the best of our knowledge, no studies are reporting VKC symptoms during it.
The study conducted by Walaa Al-Dairi et al. analyzed the impact of lockdown on patients’ quality of life with allergic conjunctivitis, and it was reported, unlike our results, that there was no important effect on the quality of life of allergic conjunctivitis during the COVID-19 lockdown .
Leonardi et al., in accordance with the EAACI guidelines , provided indications in the management of seasonal (SAC) and perennial (PAC) allergic conjunctivitis, VKC and atopic keratoconjunctivitis (AKC), highlighting that the treatment options for SAC/PAC, VKC and AKC were still valid also during COVID-19 outbreak .
This study presents some limitations; first of all, it was based on online surveys, that were retrospectively collected in December 2020. Parents’ recollections of previous clinical signs and symptoms could have been affected, and we couldn’t use medical records referring to 2019 since they focused more on clinical ophthalmologic signs rather than parents’ perceptions of symptoms, which was the focus of our inquiry. Another limitation was that we used a non-standardized questionnaire (however, to the best of our knowledge, standardized questionnaires on this topic are not available). Selection bias also should be considered since people more interested in the SARS-CoV-2 outbreak may have been more likely to answer the survey. Moreover, our study focused exclusively on the better quantifiable screen exposure represented by long-distance learning, and it didn’t focus on less quantifiable exposure, like videogames or smartphone use, or natural light exposure from sources like balconies and private gardens. Lastly, the sample size is relatively small. Thus, further studies with a larger sample size should be desirable in the future to shed light on this specific topic.