Digital eye strain or computer vision syndrome is characterized by visual disturbance and/or ocular or non-ocular discomfort associated with viewing digital display units. The term ‘computer vision syndrome’ has been used for nearly 30 years in medical literature but with the widespread popularity of other digital devices such as laptops, smartphones and tablets, ‘digital eye strain’ now seems more comprehensive and appropriate.
Symptoms of Digital Eye Strain
Digital eye strain may present as a single ‘obvious’ symptom or a vague collection of symptoms that individuals often describe as ‘tired’ or ‘heavy’-feeling eyes. Common symptoms include:
• sore eyes
• burning or stinging eyes
• blurred vision
• watery eyes
• poor concentration
• neck, shoulder and/or back pain
Causes of Digital Eye Strain
Blinking Frequency – Blinking helps keep the front surface of the eye healthy, as most blinks initiate the cycle of tear secretion, distribution, evaporation and drainage. As we stare at our digital devices, we only blink 5-7 times per minute, a 55-66% reduction compared to the average 15 times per minute under relaxed conditions!1 Many researchers believe that decreased blink rate is the primary cause of dryness among visual display unit users.2,3 Inadequate blinking not only only fails to lubricate the ocular surface, causing symptoms of dryness, it may also cause blurred vision.
Dry Eye – Dryness is commonly experienced by individuals with otherwise healthy eyes who are avid device users. As discussed above, changes in blink characteristics likely play a large role. There are other environmental and individual factors that can exacerbate dryness when using devices. Office environments often feature low humidity, ventilation fans, air conditioning and airborne dust/toner particles, which may contribute to dry eye. Digital device users who wear contact lenses are at an increased risk of digital eye strain because contact lenses interrupt with normal tear physiology, contributing to symptoms of dryness.4
Glare – Commonly experienced by computer users, glare can reduce reading speed5 and contribute to digital eye strain. The visual display unit unit is often the source of glare, but it can also come from the environment, such as improper desk lighting.
Refractive Error – Uncorrected, or an incorrect prescription for, myopia, hyperopia, astigmatism or presbyopia can make computer work less clear and comfortable. Depending on your condition, your eyes could be exerting extra focusing effort or be forced to work harder to maintain a clear image when viewing the computer screen.
Ergonomic Factors – We face a bit of ‘chicken or egg’ dilemma when discussing ergonomics in the context of digital eye strain. On one hand, an unfavourable ergonomic setup can contribute to visual symptoms. For example, if one’s computer monitor is positioned too close to their eyes and directly under a source of glare (e.g. fluorescent light), it is likely to cause their eyes to feel tired and sensitive to the light after a short period of viewing the screen.
On the other hand, non-ocular symptoms such as neck, back and shoulder pain are generally considered part of the syndrome of digital eye strain. When individuals are experiencing ocular symptoms such as blur while viewing their monitor, their posture is likely to change. They may lean toward their screen and/or slouch in their chair, putting a strain on the neck and back.
Blue Light – Whether using a computer, phone, TV or tablet, these digital sources emit blue light, the part of the visible spectrum with the shortest wavelength and highest energy. Many researchers and clinicians speculate that blue wavelength light emitted from devices contributes to digital eye strain. Blue wavelengths are scattered more than others within the eye. This may create a “visual noise“ that reduces contrast and increases the effort required to maintain visual focus. Evidence to support this association is lacking and there is little research to support the use of blue-blocking filters as a clinical treatment for digital eye strain.6 Randomized clinical trials are needed to provide high quality evidence.
Tips To Reduce Digital Eye Strain
2. Patel, S., Henderson, R., Bradley, L., Galloway, B., & Hunter, L. (1991). Effect of visual display unit use on blink rate and tear stability. Optometry and Vision Science : Official Publication of the American Academy of Optometry, 68(11), 888–892.
3. .Schlote, T., Kadner, G., & Freudenthaler, N. (2004). Marked reduction and distinct patterns of eye blinking in patients with moderately dry eyes during video display terminal use. Graefe’s Archive for Clinical and Experimental Ophthalmology, 242(4), 306–312.
4. Ranasinghe, P., Wathurapatha, W., Perera, Y., Lamabadusuriya, D., Kulatunga, S., Jayawardana, N., & Katulanda, P. (2016). Computer vision syndrome among computer office workers in a developing country: an evaluation of prevalence and risk factors. BMC Research Notes, 9(150), 150.
5. Garciai, K.D., & Wierwille, W.W. (1985). Effect of glare on performance of a VDT reading‐comprehension task. Hum Factors. 27. 163–173.
6. Lawrenson, J. G., Hull, C. C., & Downie, L. E. (2017). The effect of blue‐light blocking spectacle lenses on visual performance, macular health and the sleep‐wake cycle: a systematic review of the literature. Ophthalmic and Physiological Optics, 37(6), 644-654.