Digital Eye Strain

Digital devices and ocular well-being

Pubblicato il

Thursday, 19 July 2018

Argomento

Ocular discomfort

The Digital Eye Strain (DES), also known as Computer Vision Syndrome (CVS), is the set of eye and visual discomforts that can occur as a result of prolonged use of computers and other digital devices.

Over the last twenty years, and especially since the launch of the first iphone in 2007, we have witnessed a real revolution in our daily activities, both work and leisure: the use of digital devices has been occupying ever increasing portions of our day.

Desktops, laptops, tablets and smartphones are now used all over the world and have become indispensable for every activity, in every age group and virtually non-stop.
But what happens to our eyes?

For some years now, there has been talk of Digital Eye Strain (DES)also known as Computer Vision Syndrome (CVS)to define the set of ocular and visual discomforts that can occur as a result of prolonged use of computers and other digital devices.

Prevalence and symptoms

According to an estimate by the Vision Council of America as many as 28% of users spend up to 10 hours a day staring at digital screens, often without even taking a break. A rough estimate is that DES affects approximately 40% of adults and up to 80% of teenagers among regular users of digital devices.

Moreover, in many cases, the small size of some portable devices leads to the use of small-bodied characters, resulting in the need to bring the device closer to the eye than is the case when reading paper materials. The reduced distance implies greater eye strain in terms of accommodation and vergence.

I symptoms of DES can be grouped into two macro-categories:

1. Symptoms related to visual accommodation stresssuch as blurred vision both near and far after using the digital device and difficulty in focusing when switching from one distance to another.
2. Symptoms related to dry eyewhich may occur as a result of reduced and incomplete blinking, such as dryness of the ocular surface, irritation and burning of the eye, hypersensitivity to light and a feeling of ocular discomfort.

Although such symptoms are generally transient, they can become frequent and persistent and thus have an economic impact to the extent that they impair the efficiency of the 'digital addict'.

In 2016, the Digital Eye Strain reportbased on responses to a survey involving 10,000 US adults. The symptoms reported by respondents put the prevalence at 65%, with women slightly more affected than men (69% vs 60%). DES was more frequently reported by individuals using two or more devices simultaneously, compared to those using only one device at a time, with prevalences of 75% and 53%, respectively.

Digital Eye Strain and dry eye

A separate issue deserves dry eye, which may be associated with DES. In this case, dry eye may have an initial environmental cause, as computers are often placed in rooms/offices where the air is very dry and, in addition, the use of air conditioning, whether hot or cold, can exacerbate the process of tear film evaporation.

Furthermore, fixing digital screens can affect blinking. In particular, it has been shown that the use of digital screens produces a considerable increase in the number of incomplete blinks, in which the upper eyelid fails to cover the entire cornea.

This alteration in blinking is very likely to induce dryness of the lower corneal surface and given the already high prevalence of dry eye in women, contact lens wearers and elderly patients, any reduction in the amplitude of blinking is likely to further exacerbate their ocular suffering.

Digital Eye Strain: how to measure it

The first approach to DES must be a comprehensive eye examination aimed at ruling out any ocular pathologies, but also at ascertaining that any refractive correction is appropriate to that specific person's visual needs. It is, therefore, necessary to measure near and far visual acuity, blink frequency and completeness, pupil characteristics, ocular angle, and the type and number of digital devices habitually used.
Objective measurements can be combined with questionnaires that provide a picture of the subjective perception of eye fatigue.

DES: how to handle it

Ocularly, possible remedies for DES include:

1. Prescription of an appropriate refractive correction to be used in the working environment. In particular, adequate correction of astigmatism may be appropriate, since an astigmatism of 0.5 to 1 D can already accentuate the symptoms of DES.
2. Improve accommodation and/or vergence.
3. Use lenses with a filteralthough the usefulness of blue light filters is controversial.
4. Improving the conditions of ocular surface.

With reference to environmental aspects, attention should be focused on:

1. Ensure optimal ambient lighting in order to reduce glare (glare) and reflections from the screen.
2. Avoid looking at the screen at too close a distance
3. Stress the need to take regular breaks.

In short 'a little less and a little better' could be the slogan to define the time we spend using our inseparable digital devices!