PRODUCT PROFILE
Digital device use and dry eye It’s not just our computers that are streaming, writes Meena Puar, as she reviews the link between screen use and dry eye... Figure 1. Common symptoms associated with CVS
The demands of modern society have resulted in us sitting in front of digital devices for hours and hours. At a touch of the button, we can do anything from ordering our weekly food shop, catching up with friends and family, or watching the latest ‘must-see’ boxsets and film releases. The list is endless. The use of smartphones, tablets and laptops has led to many of us experiencing visual symptoms known as ‘computer vision syndrome’ (CVS), better known now as ‘digital eye strain’. The common symptoms of CVS listed in Figure 1 may also be linked to environmental factors, such as poor ergonomics, air pollution, improper lighting, glare and decreased humidity in air-conditioned rooms.
SNAPSHOT OF STATISTICS In the UK, digital device use has increased substantially in recent years. A 2016 study revealed that adults typically spent four hours and 45 minutes per day using digital media1. A similar study also showed that all age groups had increased their use of digital devices2. A more recent (2020) crosssectional study by Golebiowsi et al3 revealed that the daily duration of smartphone use correlated with levels of dry eye, confirmed by a dry eye assessment and survey. The latter study involved 916 children with the signs and symptoms of dry eye, which improved after electronic device use was reduced. During the Covid-19 pandemic, screen time has reached an all-time high, and the impact of this behaviour on ocular surface health has been clearly established4. For some, Zoom meetings have now become part of the norm. From work meetings,
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Vision Now APRIL 2021
home schooling, exercise classes and even virtual birthday parties, the list goes on. In this review, we will take an in-depth look at the relationship between screen use and dry eye disease.
DRY EYE DISEASE DEFINED Dry eye disease is a multifactorial disease. The Tear Film and Ocular Surface Society (TFOS) Dry Eye Workshop (DEWS) II Report5 defines dry eye as: “...a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface. It is accompanied by increased osmolarity of the tear film and inflammation of the ocular surface.” Approximately one in five adults suffer from dry eye disease, which translates to more than 13 million people in the UK6. Whilst seated in front of the screen for a long period of time, there are two factors that play a part in exaggerating dry eye disease and its symptoms. This includes a reduction in the blinking rate and incomplete blinks. Firstly, it is important to understand what happens when we blink. During a complete
blink, the meibomian glands are activated. These glands line along the edge of the eyelids (Figure 2), and they play a crucial role in producing the oily layer of the lipid component of the tear film. The meibum is released onto the lid margins for dispersion onto the tear film. This combined effort is of the orbicularis oculi and muscle of riolan. During the complete blink pattern, the upper and lower tear film mix.
REDUCED AND INCOMPLETE BLINKS Several studies have documented the link with reduced blink rate and computer use. A study conducted by Patel et al 7 reported a mean rate of 18.4 blinks per minute under relaxed conditions, reducing to 3.6 blinks per minute during computer usage. In another study8, blink rates were found to be reduced for all reading tasks, but significantly fewer blinks were noted when patients were reading with backlit LCD screens. Reducing the blink rate can reduce visual quality, giving rise to tear film instability, and consequently lead to dry eye symptoms9. If the blinks are incomplete, tears will not distribute over the ocular surface and this results in increased evaporation and an unstable tear film10. In addition to this,
Figure 2. Meibomian glands prevent tear film evaporation
