Digital Dry Eye

Introduction

The digital environment is ubiquitous in modern life (Figure 1). A global prevalence of digital eye strain has been estimated to affect on average 70.7% of an adult population (Wolffsohn et al., 2023), but ranged widely from 31.9% in bank workers in Italy (Mocci et al., 2001) to 97.3% in university students in Saudi Arabia (Altalhi et al., 2020). The Tear Film & Ocular Surface Society (TFOS) Workshop (www.tearfilm.org), entitled ‘A Lifestyle Epidemic: Ocular Surface Disease,’ establish the direct and indirect impacts that everyday lifestyle choices and challenges have on ocular surface health (Craig et al., 2023).

• The digital environment (of relevance to eyes) is defined as any technology requiring viewing of a digital display for a cognitive task.

The potential effect(s) of digital device use on vision and eye health have been studied for over 20 years (Dain et al., 1988), highlighted by several recent literature reviews (Mehra and Galor, 2020, Sheppard and Wolffsohn, 2018, Coles-Brennan et al., 2019, Gowrisankaran and Sheedy, 2015, Kamøy et al., 2022). The most commonly quoted definition is from the American Optometric Association that states “Computer vision syndrome, also referred to as digital eye strain, describes a group of eye- and vision-related problems that result from prolonged computer, tablet, e-reader and cell phone use” (American Academy of Optometry, Accessed March 2022). However, this definition does not exclude those who experience these ‘problems’ when conducting similar non-digital tasks and key terms such as “prolonged” are not defined. Hence the TFOS Lifestyle Workshop Digital Environment report (Wolffsohn et al., 2023), defined the term:

• Digital eye strain as “the development or exacerbation of recurrent ocular symptoms and/or signs related specifically to digital device screen viewing”.

The term ‘digital eye strain’ was used in preference to ‘computer vision syndrome’ as ‘computer’ technology can be considered quite specific and ‘vision” is less appropriate terminology than ‘strain’ meaning to “over-exert” (2022) relating to the ‘eye’. Other past terminology includes: ‘repetitive strain disorder’ (Munshi et al., 2017), eye fatigue (Meyer et al., 2021), ‘eye related pain’ (Thorud et al., 2012), ‘asthenopia’ (Chu et al., 2014, Meyer et al., 2021) and even ‘video game vision’ has been proposed (Mylona et al., 2020).

Clinical Evaluation

Risk Factors

Risk factors include:

• Longer screen time (>4-5 hours) (Inomata et al., 2019)
• poor screen resolution (Iqbal et al., 2021)
• closer working distances / smaller font (Long et al., 2017)
• surround luminance / glare (Iqbal et al., 2021, Wolska and Switula, 2015, Janosik and Grzesik, 2003, Shieh, 2000)
• suboptimal refraction (Hatchett et al., 2019, Jijiashvili, 2021, Mazuryk and Gervautz, 1996, LaValle et al., 2014, Hillmann, 2019)
• pre-existing ocular surface disease (Talens-Estarelles et al., 2020)

Signs

Symptoms of digital eye strain are non-specific and heterogeneous, and include eye strain, ocular tiredness, ocular soreness, ocular pain, blur, burning, ocular dryness and light sensitivity (Shantakumari et al., 2014, Portello et al., 2012). Some definitions also include headache and neck/shoulder pain (American Academy of Optometry, Accessed March 2022). It has been proposed that eye strain symptoms may derive from two distinct mechanisms (Sheedy et al., 2003):

• External symptoms – linked to the ocular surface including dry eye disease (Craig et al., 2017) and contact lens induced dry eye (Dumbleton et al., 2013), including:
  • Dryness
  • Tearing
  • Irritation
  • Burning
• Internal symptoms – that have been associated with accommodation and/or binocular vision dysfunction (Sheedy et al., 2003), including:
  • Blur
  • Tiredness
  • Ache

However, there remains some ambiguity regarding the characteristic clinical sign(s) of digital eye strain, at least in part because its physiological basis is uncertain.

Potential clinical indicators of digital eye strain may include measures of visual function (such as accommodation and convergence function, critical flicker fusion frequency and pupil responses) and ocular surface health (tear volume, stability, evaporation rate and osmolarity, blinking characteristics and meibomian gland parameters) (Fjaervoll et al., 2022).

Differential Diagnoses

When faced with a patient complaining or eye dryness or stain when using a digital device, it is first important to ascertain whether similar symptoms occur in non-digital environments. If so, refer to the differential diagnoses for dry eye disease.

If the symptoms are exacerbated by or only occur when using digital devices, consider (Wolffsohn et al., 2023):

• Ocular surface disease – disruption to the ocular surface or tear film can be a precursor to dryness symptoms when blinking is reduced, such as in a digital environment.
• Binocular vision – patients can report eye strain with the eyes are not working together in synchrony, especially during long duration, high cognitive load near tasks.
• Refraction – digital environments often require high acuity demand near tasks, for which the individual’s refractive correction may not be optimised.

Investigations

Assessment of a patient reporting digital eye strain should include (Wolffsohn et al., 2023):

• Tear film:
  • Lids and lashes including anterior blepharitis, lid margin telangiectasia and staining, and the meibomian gland orifices and structure (through meibography)
  • Stability, ideally using a non-invasive breakup time method
  • Volume, ideally measuring the tear meniscus height viewed under infrared light
  • Lipid later thickness with meibography
  • Osmolarity
• Ocular surface
  • Staining of the cornea and conjucntiva
• Blinking – rate and completeness
• Binocular vision
  • Accommodative lag and speed
  • Phoria
  • Critical flicker fusion frequency
• Refraction
  • Screen distance requirements, pushing maximum plus to negative accommodative strain

Management and Advice

Although many studies have been conducted to evaluate treatments for digital eye strain, the quality of these studies is variable (Wolffsohn et al., 2023). The intervention with the strongest evidence of a benefit to individuals with digital eye strain is:

• Oral omega-3 fatty acid supplements.

Well researched treatments which have been found to have no beneficial effect in ameliorating digital eye strain are blue light blocking and anti-oxidants.  Other strategies where there is some evidence that they may be affective include:

• Optimising the refractive correction for the screen distance
• Regular blink and break reminders
• Placing the screen lower than the user’s eyes and avoiding reflections
• Increasing the screen size / font and potentially switching to e-paper
• Increasing the humidity and decreasing air-conditioning in the users environment
• Limiting screen use to under 4-5 hours a day and / or reducing the cognitive demand of the task(s)

Areas which warrant further research include:

• Oculomotor exercises
• Dry eye treatments
• Yoga
• Traditional medicines

Prognosis

It is unknown whether untreated digital eye strain can lead to increased symptoms of eye health problems in the future. However, as well as ocular, visual and musculoskeletal symptoms, the presence of digital eye strain has been associated with lower quality of life (Hayes et al., 2007) and reduced work productivity (Daum et al., 2004). Hence, trying to minimise digital eye strain is warranted.

Prevention: Optimising the ocular surface / tear film, binocular vision and refraction of all patients should minimise the chances of them experiencing digital eye strain when circumstances require extended period of digital device use.