Ibrahim Suleiman, Ph.D.
These days, it seems like everyone is staring at a computer screen, phone or other digital devices. Setting limits on screen time is necessary due to risks that are associated with prolonged exposure to these devices. Too much screen time has been associated with depression, anxiety and digital eye strain. This article elucidates the risks of too much screen time on vision, and what can be done to avert such risks.
Over 50 per cent of people, who work in front of a computer screen, experience a condition called digital eye strain. Common symptoms of digital eye strain include: eye fatigue, dry eye, irritated or itchy eyes, blurred vision, red eyes, eye twitching, and headaches. These symptoms are thought to be caused by overexposure to high-energy visible light or ‘blue light’ that is emitted by digital devices. Blue light has a wavelength of 380 nm to 500 nm, which means that it is one of the shortest, highest-energy wavelengths that human beings can perceive. These waves penetrate deep into the eyes, and create a glaring effect, which results in irritation and strain.
Eye strain, often, is caused by excessively bright light, either from the outdoor sunlight that comes in through a window, or from harsh interior lighting. When using a computer, your ambient lighting should be about half as bright as what is typically found in most offices or rooms. Eliminate exterior light by closing drapes, shades or blinds. Reduce interior lighting by using fewer light bulbs, or use lower intensity bulbs. Adjusting your computer display settings can help reduce the risk of eye strain and fatigue. This includes adjusting your device’s brightness to approximately the same as the brightness of your surrounding workstation.
Eye care specialists can treat the symptoms of digital eye strain, but there are no studies yet that can prove long-term damage. Some laboratory studies suggest that increased exposure to blue light can damage the retinal tissue, but many researchers refute this assertion, and claim that electronic devices emit only small amounts of energy. Interestingly, the rates of near-sightedness (myopia) have increased globally. Is this a coincidence, or could it be a direct result of our growing screen addiction?
Numerous people continue to wonder if prolonged exposure to screens could lead to near-sightedness. The rate of near-sightedness in children and the use of screens have increased dramatically in the past 20 years. Studies are yet to establish the exact correlation between screen time and near-sightedness. However, it is important to note that prolonged screen time keeps you indoors, thereby preventing you from getting optimum natural daylight exposure, which is critically important to the developing eyes.
Long stretches of screen time also cause the eyes to get dry and irritated. Studies show that people of all ages blink far less often when concentrating on screens, which, in turn, causes the eyes to dry out. Blinking is very important when working at a computer. It moistens your eyes to prevent dryness and irritation. Tears coating the eye evaporate more rapidly during long non-blinking phases, and this can cause dry eyes. If you experience dry eye symptoms, ask your eye doctor about artificial tears for use during the day. To reduce your risk of dry eyes during computer use, try this exercise: blink 10 times, every 20 minutes, by closing your eyes as if you are falling asleep (very slowly). This will help re-wet your eyes.
The other problem with screen time is its effect on sleep. Research shows that the blue light from the computer and device screens, when used in the evening, alters the brain’s sleep rhythms. The brain reads the screen light as ‘daytime’, and shifts the body’s circadian rhythm. The exciting content of many video games and movies can also wind someone up when they should be winding down for bed.
Setting a limit on daily screen time, and sticking to these limits is very important for your eyes. These limits may include: establishing screen-free zones (e.g. avoid using smartphones, while in the restaurant, at the dinner table, and while in bed), and adopting some simple eye exercise regimen.
One commonly recommended eye exercise, when using a computer or other screen device, is the ‘20-20-20 rule’. Every 20 minutes, look away from the screen for 20 seconds, and focus on something. at least, 20 feet away. Use of a timer as a reminder for the ‘20-20-20 rule’ is encouraged. Otherwise, someone could choose to install a software programme that turns the screen off automatically at set times.
Another beneficial eye exercise is to look far away at an object for 10 to 15 seconds, then gaze at something that is up for close to 10 to 15 seconds. Then look back at the distant object. Do this 10 times. This exercise reduces the risk of your eyes’ focusing ability to ‘lock-up’ (a condition called accommodative spasm), after a prolonged screen time. Also, remember to blink frequently during the exercises to reduce your risk of computer-related dry eye.
You should also consider using computer glasses for prolonged screen time. Computer glasses are a good choice, if you wear bifocals or progressive lenses, because these lenses are not generally optimal for the distance to your computer screen. You may also want to consider photo-chromic lenses, or lightly tinted lenses for computer eyewear to reduce your exposure to potentially harmful blue light that is emitted by digital devices.
Finally, go for an annual eye examination. You may be able to tell if your eyes are tired or irritated. But it is harder to tell if they (your eyes) are developing a vision problem. Only a comprehensive eye examination, by an eye doctor (an ophthalmologist or optometrist), can reliably tell if you risk developing visual impairment. During the eye examination, be sure to tell your doctor how often you use a computer and other digital devices at work and home. Measure how far your eyes are from your screen when you sit at your computer, and bring this measurement to your examination, so your eye doctor can test your eyes at that specific working distance.
Until we have more evidence from longitudinal studies, there will be more questions than answers regarding the specific effects of screens and blue light on our vision. However, it is better to be safe than to be sorry.
