The rise in digital eye strain that can be associated with modern lifestyles contributes both a significant challenge and a major opportunity for eye care practitioners to try and address. Any doubts about the significance of increasing use of digital displays might be quashed by reading the survey published in Optician 30.03.2018. As with dry eye disease, there seems to be a number of contributory factors and effective management needs to look into the contribution each of these makes and modify them in a way that minimises symptoms but without impact on vision or lifestyle.

This interactive exercise offers an overview of the published literature in this area and then offers a case study for you to discuss and report back on your findings and thoughts. But first, a few main points.

What is digital eye strain?

Formerly often described as computer vision syndrome, digital eye strain (DES) describes the range of ocular and visual symptoms associated with the use of computers, laptops, smart phones, tablets and other digital displays.

Is there and evidence base for DES?

Yes – references 1 to 5 offer a good review and the term DES is now accepted in the eye care community. The evidence base is not reliant upon subjective comfort surveys but include physiological observation linked, for example, to tear film and phoria breakdown.

Why is DES a concern of recent times only?

Just as AMD was little heard of when life expectancy was short, awareness of DES has correlated exactly with the increase in use of digital displays, both in terms of their nature and also how they are being viewed. A 2016 EU report showed that 20% of European workers no longer worked ‘standard’ or nine-to-five working shifts. Constancy of artificial lighting, air humidity and controlled temperature combined with near work outside the standard circadian rhythm presents challenges to the visual system. A 2016 US survey found 90% of adults use one or more digital display devices for more than 2 hours a day. Table 1 shows some further results of this survey.

2016 use of digital displays in the US

  • 90% use digital device 2+ hours per day
  • 60% for 5+ hours per day
  • 65% have some digital eye strain symptoms
  • 90% with digital eye strain use two or more devices
  • 76% view device before bed
  • 90% do not discuss digital usage with their eye care practitioner

Table 1

Furthermore, many individuals spend 10 or more hours per day viewing these displays, frequently without adequate breaks. The small size of some portable screens may necessitate reduced font sizes, leading to closer viewing distances, which will increase the demands on both accommodation and vergence. The days of an assumed 40cm working distance for near work are long gone. Professor Mark Rosenfield’s paper5 offers an excellent review of the epidemiology of DES.

 What are the symptoms?

Around 40% of adults and up to 80% of teenagers may experience significant symptoms, both during and immediately after viewing electronic displays.5 Visual symptoms may include transient blur, phoria breakdown-type symptoms, discomfort glare and asthenopia. Ocular and physical changes may include dry eye problems, red eye, and postural discomfort.

Why does it happen?

Prolonged concentrating near work, changed angle of gaze, closer working distance looking at often smaller fonts with less contrast and with more glare than might be presented by printed text lead to increased demand on vergence and accommodation, reduced blink rate and incomplete lid closure on blink, increased evaporation of tears and stiffness and discomfort linked to maintained posture. This can be exacerbated by long periods of viewing often at odd times of the day.

Attempting to read text of a size at or close to the threshold of resolution for an extended interval may produce significant discomfort and it has been demonstrated that a two-times reserve was appropriate for young, visually normal subjects when reading from a laptop computer. In other words, for sustained comfortable reading, the text size should be at least twice the individual’s visual acuity. However, higher values may be necessary for older patients, or individuals with visual abnormalities.

The article is available as source material for this exercise and it is important to read it through – there are a new set of multiple choice questions to be completed, to check understanding of the material, before undertaking the interactive exercise. The exercise involves deciding upon a suitable aid for a patient and predicting any problems with the outcome.

How can it be investigated?

Table 2 shows a list of useful questions when assessing a patient with possible DES. It is essential to build up a picture of how the patient uses their digital media if useful advice is to be offered.

Essential information when investigating possible DES5

  • Number and type of devices being used (including desktop, laptop and tablet computers and smartphones)
  • Viewing distance and gaze angle for each device
  • Duration of use for each device
  • Monitor size (for a desktop computer, also ask about the number of monitors being used)
  • Type of task being performed on each device
  • The size of the critical detail being observed during the task

Table 2

A full refraction, binocular assessment, ocular surface analysis and eye health check is essential as each may reveal contributory impact which, as well as lifestyle modification advice, may need to be addressed.

What can be done?

As stated above, a number of possible challenges might need addressing alongside offering advice on the usage (time between breaks, environment, lighting, posture, and so on). Amplitude of accommodation and refraction are important. It has been reported that the presence of 0.50 to 1.00DC of uncorrected astigmatism may produce a significant increase in symptoms. Accommodative reserve and near vergence need addressing to ensure there are adequate reserves. Tears and blinking behaviour need assessment and usually a programmed intervention. Improved visual quality helps and attempts have been found to be successful when both improving the image quality and also by correcting, and in some cases supporting, near vision, perhaps with a near addition. Sudden increased near demand will usually benefit from near help and many lenses now exist aimed at offering low addition support. These may only be considered once other factors, particularly the binocular status, have been assessed. Introducing an unnecessary addition at pre-presbyopic ages comes with some warnings.6,7

Before you attempt the multiple choice questions online, please refer to the papers cited. Reference 5 is of particular value.

References

  1. Portello JK, Rosenfield M, Chu CA. 2013. Incomplete blinks and computer vision syndrome. Optometry and Vision Science, 90 (5), 482 – 487.
  2. Portello JK, et al. 2012. Computer-related visual symptoms in office workers. Ophthalmic & Physiological Optics, 32 (5), 375 – 382.
  3. Rosenfield M, et al. 2011. Font size and viewing distance of hand-held smart phones. Optometry and Vision Science, 88 (7), 795 – 797.
  4. Rosenfield M. 2011. Computer vision syndrome: A review of ocular causes and potential treatments. Ophthalmic Physiological Optics,  31 (5), 502 – 155.
  5. Rosenfield M. Computer vision syndrome aka digital eye strain. Optometry in Practice, 2016, Volume 17: Issue 1, 1 – 10
  6. M. Wahlberg, S. Abdi, and R. Brautaset. Treatment of accommodative insufficiency with plus lens reading addition: is +1.00 D better than +2.00 D? Strabismus 18 (2):67-71, 2010
  7. Vedamurthy I, Harrison WW, Liu Y, Cox I and Schor CM. The Influence of First Near-Spectacle Reading Correction on Accommodation and Its Interaction with Convergence - Invest Ophthalmol Vis Sci. 2009 Sep;50(9):4215-22.


Now attempt the six multiple choice questions as the next step of this module. You must get all six correct to proceed to the interactive exercise.