In recent months, research has illustrated the impact of COVID-related changes to the childhood visual environment. As the “new normal” evolves, it’s too early to tell whether the necessities and habits have altered over the past two years. Home-based schooling and increased screen time has had a measurable impact on myopia incidence and progression in several countries (Xu et al, 2021; Wang et al, 2021; Mohan et al, 2022; Yum et al, 2021).

Children aged 6 to 8 years in Hong Kong decreased their outdoor time from 1.3 to 0.4 hours per day during the pandemic; screen time increased from 2.5 hours to 6.9 hours per day (Xu et al, 2021). Children aged 10 to 16 years in India increased their digital device time from an average of 1.9 to 3.9 hours per day (Mohan et al, 2021).

Almost 40% used digital devices for longer than five hours per day, compared to only 2% before the pandemic (Wang et al, 2021). Even children under age 3, without schooling demands, increased their screen time—multicountry data showed higher screen time in children under age 3 was correlated with higher socioeconomic status and parental screen time (Mohan et al, 2022).

Aside from the impact on myopia prevalence, new data also indicates an increase in children experiencing digital eye strain (DES), also known as computer vision syndrome. DES can present with symptoms related to accommodation or binocular vision stress, and/or symptoms related to dry eye (Sheppard and Wolffsohn, 2018). The authors also noted that frequency may be well over 50% in adults.

There is a scarcity of data on DES in children, with a 2015 meta-analysis indicating a 20% frequency of asthenopia in children, the majority of whom did not present with visual acuity or refraction issues (Vilela et al, 2015). Asthenopia is a catchall subjective description that can encompass symptoms due to refractive, binocular vision, or ocular surface abnormalities, similar to the broad range of symptoms encompassed by DES.

Fast forward several years, and this 20% frequency has at least doubled. A parent survey undertaken in India, when children were attending online classes at home, found 50% of children reported suffering digital eye strain (Mohan et al, 2021). The most common symptoms noted in the study were itching and headache, with 13% reporting moderate and 11% reporting severe symptoms. Digital eye strain was predicted by the use of smartphones for games, closer device distance (less than 18 inches), longer duration of device use (more than five hours per day), male gender, and age over age 14 (Mohan et al, 2021).

Digital device use was shown to be significantly associated with pediatric dry eye disease in a 2016 Korean study. Involving almost 1,000 children aged 6 to 11 years, dry eye disease was found in 9% of older (9 to 11 years old) and 4% of younger (6 to 8 years old) children (Moon et al, 2016). Children who had dry eye disease spent an average of 3.2 hours per day using smartphones, compared to only 0.6 hours per day in children who did not have dry eye. Four weeks of smartphone cessation improved clinical signs as well as subjective symptoms in these children.

There are two key concerns in this worrying trend. First, children are less likely to report dry eye symptoms compared to adult patients who have similar ocular signs (Han et al, 2013). Second, dry eye is typically a chronic condition, and longer duration of dry eye disease can lead to worsening symptoms in a proportion of patients (Lienert et al, 2016). The combination of the potential for delayed diagnosis and earlier onset of symptoms add up to a future wave of dry eye disease in the adults of tomorrow, alongside the wave of myopia (Holden et al, 2016).

The best action we can take today is to proactively manage ocular surface signs and symptoms in our young patients. In addition, providing advice on balancing the visual environment and decreasing screen time will benefit their vision, ocular surface, and retinal health now and into the future. CLS

References

1. Xu L, Ma Y, Yuan J, et al; Myopic Epidemiology and Intervention Study. COVID-19 Quarantine Reveals That Behavioral Changes Have an Effect on Myopia Progression. Ophthalmology. 2021 Nov;128:1652-1654.
2. Wang J, Li Y, Musch DC, et al. Progression of Myopia in School-Aged Children After COVID-19 Home Confinement. JAMA Ophthalmol. 2021 Mar 1;139:293-300.
3. Mohan A, Sen P, Peeush P, Shah C, Jain E. Impact of online classes and home confinement on myopia progression in children during COVID-19 pandemic: Digital eye strain among kids (DESK) study 4. Indian J Ophthalmol. 2022 Jan;70:241-245.
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