Screens, Eye Strain, Blue Light...What's the Rub?
In today’s world, we are all looking at screens more than ever before. This screen time comes at all ages. Almost all jobs require more computer and technology use than 20 years ago. Grandparents are keeping up with their grandkids via mobile phones and computer screens. Students are on chromebooks or iPads issued from their school district. Toddlers are watching videos on their parent’s iPads.
With this increased screen time, a new condition has developed...computer vision syndrome or digital eye strain. Studies show between 50-65% of adults report symptoms of digital eye strain. As you will see, this is a problem that involves more than just our eyes and visual system. It also is involves ergonomics and our muscular system.
First let’s get rid of an important myth. The fact is there is no evidence that blue light from digital screens is harmful to the health of our eyes. Blue light is all around us. The blue light we get from sunlight is far more than the blue light from screens. That doesn’t not mean that blue light causes no issues, it just does not harm our eyes.
Blue light does disrupt our circadian rhythm. An area of the brain called the hypothalamus regulates circadian rhythm. The retina within the eye contains special photosensitive cells that communicate directly with the hypothalamus. These cells help in “setting” our circadian clock. The retina essentially provides the hypothalamus with the lengths of daytime and nighttime. The hypothalamus sends this information to the pineal gland, which produces the hormone melatonin. The secretion of melatonin is greatest at night and lessens during the day. If the retina is receiving stimulation from blue light at midnight, it interprets this as being daylight. This means the individual should be awake which requires a decrease in melatonin production. As you can see this could greatly impact one’s sleep schedule.
The most common cause of eye strain is dry eye syndrome. Dry eye syndrome is increased with screen time for several reasons. First our blink rate is reduced by 30-50% when we are looking at a screen. The blinks that do occur are more likely to be partial blinks, which are less effective than complete blinks. Our blink is responsible for redistributing the tear film evenly over the surface of the cornea. If the tear film breaks down, it results in blurry or fluctuating vision and possibly discomfort. With each blink, the muscles within our eyelids also squeeze oil from the oil glands that line the lids near our eyelashes. These oils are responsible for preventing our tear film from evaporating from the surface of our eye too quickly. Also, if our lids aren’t pushing the oil through these glands, these glands may begin to atrophy over time making the problem worse.
There can be eye strain from uncorrected refractive error such as nearsightedness, farsightedness or astigmatism. In this situation, glasses, contact lenses and possibly LASIK could offer improvement in a person’s symptoms.
Another cause could be that the two eyes don’t work together when focusing on screen. This could be due to the alignment of the eyes or a significant difference in refractive error between the two eyes. For instance, if one eye is more nearsighted than the other it will have a closer point of focus than the eye that is less nearsighted. Maybe one eye is fixated slightly off center from the other eye when looking at a target at the same distance. A comprehensive eye exam with your doctor is important to rule out conditions like this or to treat the condition if something is revealed during the examination.
The majority of headaches are not related to the eyes. A comprehensive eye exam with your doctor will determine whether there is an ocular cause of your headaches or if something else is causing the headaches.
Again, uncorrected refractive error such as nearsightedness, farsightedness and astigmatism can cause headaches. Glasses, contact lenses and LASIK are again possible solutions to this problem.
Some headaches can be muscle related from how we position are bodies while looking at computer screens and tablets whether in the office, at home or on the go. If your neck or shoulders are placed in awkward positions, this can lead to problems. You don’t want to have your neck bent backwards to look up at screens or be hunched over a screen with rounded shoulders.
The following things can decrease the risk of computer vision syndrome or digital eye strain.
- Comprehensive eye exam – This will discover any uncorrected refractive error, assess the ability of the eyes to work together, determine if dry eye syndrome is present and asses the overall health of each eye.
- Lighting – When looking at a screen, less ambient light is often needed.
- Minimize glare – Eliminating glare from other light sources such as windows, doors and room lighting can be helpful.
- Adjust display
- Adjust text size and contrast – often black lettering on a white background works best.20 – 20 – 20 rule – Every 20 minutes look at something 20 feet away for 20 seconds.
- Adjust color temperature – Nightshift on Apple products will warm the color of the displays.Blink – Simply consciously blinking our eyes can redistribute the tear film and improve both vision and comfort.
- Take breaks – Scheduling breaks throughout the day are effective at both helping the eyes and relaxing the muscles in our neck and shoulders.
- Modify workstations – Align the top of the screen to be slightly below eye level. This places it in a good ergonomic position.