There were only 6.25 million personal computers and no smartphones in 1993. And today, almost every person carries a smartphone, with not much difference comparing a phone and a PC. Mobile devices and computers deliver countless benefits, however, harmful blue light exposure can lead to digital eye strain, an emerging public health in this era. Digital eye strain is a condition characterized by visual disturbance and/or ocular discomfort related to the use of digital devices and resulting from a range of stresses on the ocular system, including glare, defocus, dryness, fatigue and discomfort. Report has shown that 65% of adults experienced digital eye strain after prolonged use of electronic devices, with 60 hours a week accessing content online (1).
How does blue light affect the eyes?
Digital eyestrain
Blue light from computer screens and digital devices can decrease contrast leading to digital eyestrain. Fatigue, dry eyes, bad lighting, positioning in front of the computer can cause eyestrain. Symptoms of eyestrain include sore or irritated eyes and difficulty focusing.
Retina damage
In the visible spectrum, short-wave blue light with wavelength between 415 nm and 455 nm is closely related to eye light damage. As blue light has short wavelength, the focus is not located in the center of the retina but in front of the retina, leading to the worsening of visual fatigue and nearsightedness. Blue light has shown to increase reactive oxygen species (ROS) production in corneal epithelial cells and trigger inflammation of human corneal epithelial cells.
Part of the visible light spectrum blue light is the high-energy light just beyond the potentially harmful ultraviolet light.
Since the eye is not good at blocking blue light, nearly all visible blue light passes through the front of the eye and reaches the retina, the cells that convert light for the brain to process into images. The blue light-induced retinal damage is mediated by mitochondrial respiratory enzymes, where ROS is generated, causing ultrastructural damage and mitochondrial-dependent cell death in the retinal pigment epithelium (RPE) of the eye, which protects the outer retina from excessive high-energy light and light-generated oxygen reactive species, as well as maintaining retinal homeostasis. The vulnerability of RPE to ROS can lead to cellular dysfunction, such as age-related macular degeneration (2).
(Adapted from Iristech.co)
Effects of blue light on circadian rhythm
Researchers have found out that blue light can interrupt body clock by regulating the secretion of melatonin in pineal gland, which function to increase or decrease cortisol expression according on time of day. When blue light is excessive, particularly during night when melatonin production peaks, it does not only damage the retina but also stimulate the brain, inhibit melatonin secretion and increase corticosteroid production, directly affecting sleep quality. Sleep disorders can lead to the increase in corticosteroid production and reduce tear secretion, hence, the occurrence of dry eyes (3).
How to protect your eyes against blue light?
Taking supplements containing lutein and zeaxanthin is a win for your eye health. They are part of the carotenoid family that defend your body against unstable molecules such as free radicals. Besides that, the molecule alpha-tocopherol, a vitamin E derivative, also works as an antioxidant in the human eye, preventing cells from dying (4).
Besides that, practicing 20-20-20 rule can decrease digital eyestrain. With every 20 minutes, look at something 20 feet away for 20 seconds. This could help relax the eye muscles for 20 seconds and gives the brain a much-needed break.
Taken together, preventative measures to protect your eyesight are essential as part of your health and wellbeing. By looking after your eyes when you are younger, it can help reduce the risks of developing problems with your eyesight and reduce the risk of eye disease and even sight loss.
References:
1. Coles-Brennan C, Sulley A, Young G. Management of digital eye strain. Clin Exp Optom. 2019 Jan;102(1):18-29. doi: 10.1111/cxo.12798. Epub 2018 May 23. PMID: 29797453.
2. Godley BF, Shamsi FA, Liang FQ, Jarrett SG, Davies S, Boulton M. Blue light induces mitochondrial DNA damage and free radical production in epithelial cells. J Biol Chem. 2005 Jun 3;280(22):21061-6. doi: 10.1074/jbc.M502194200. Epub 2005 Mar 29. PMID: 15797866.
3. Zhao ZC, Zhou Y, Tan G, Li J. Research progress about the effect and prevention of blue light on eyes. Int J Ophthalmol. 2018 Dec 18;11(12):1999-2003. doi: 10.18240/ijo.2018.12.20. PMID: 30588436; PMCID: PMC6288536.
4. Abdel-Aal el-SM, Akhtar H, Zaheer K, Ali R. Dietary sources of lutein and zeaxanthin carotenoids and their role in eye health. Nutrients. 2013 Apr 9;5(4):1169-85. doi: 10.3390/nu5041169. PMID: 23571649; PMCID: PMC3705341.