In today's modern technologically active world, this has become one of the most common question I hear from patients every single day. Most of us nowadays spend an enormous amount of time on screens. From computer displays and mobile devices to e-readers and video game consoles it seems like there is an increasingly small amount of activities that do not involve a screen of some kind. These devices can improve productivity and they can be great sources of entertainment, but what are the potential health impacts of this increased screen time?
The sky is blue, so how can blue light be bad?!
In order to fully understand why increased screen time can be potentially harmful to our eyes, we need to first understand how our eyes view and process light. The electromagnetic spectrum is made up of varying wavelengths of electromagnetic energy, and the photoreceptors in our eyes are sensitive to a narrow band of these wavelengths in the visible light spectrum. As the wavelength shortens, the intensity of the electromagnetic energy increases. On the longer end of the wavelength spectrum with less energy than visible light is infrared radiation, and on the shorter wavelength end of the spectrum with higher amounts of energy than visible light is ultraviolet radiation. Ultraviolet radiation is well known to contribute to a host of eye problems including cataracts and macular degeneration. It is common knowledge that sunglasses with good ultraviolet protection can help limit this potential damage when worn outside. Right on the border of the visible light spectrum and the ultraviolet spectrum is a range of electromagnetic energy known as high energy visible light (HEV). This band of energy is interpreted by our eyes as blue light, and it is a very common component of the light emitted from our many screens and devices. Our brains recognize this light in a way that activates the areas responsible for alertness, and constant exposure to this type of light could potentially lead to eyestrain and other eye health issues.
So you're saying staring at my computer for 15 hours a day is bad?
In pretty much every exam I do with a patient I ask about screen time and computer usage, and it is not uncommon for a patient to tell me that they are on some sort of screen for up to 15 hours a day. That is a huge portion of the day, and during that time the eyes are being constantly bombarded by this HEV blue light. This can lead to significant eyestrain and fatigue, and potentially eye health issues down the road. In order to protect the very delicate retina from damage, the human eye has evolved in such a way that the crystalline lens acts as a barrier that absorbs some UV light. This is the exact reason cataracts form, but to a large extent it is a protective mechanism from retinal damage. Unlike UV light, the HEV blue light emitted from devices is not absorbed by the crystalline lens, and basically all of it makes its way to the retina. This is why this type of light is potentially so damaging. It is just below the spectrum where the eye absorbs it, but it is just high energy enough that it can possibly still cause similar damage. Obviously going outside without sunglasses is giving the eyes a massive dose of potentially harmful UV radiation (and this is why everyone should always wear sunglasses), but consistent long term exposure to this HEV blue light also needs to be addressed.
Well I'll get fired from my job if I can't use a computer.....so what should I do?
In order to address this growing concern, lens manufacturers have been developing lens coatings that block just this narrow band of electromagnetic wavelengths. This will allow colors to remain largely unchanged while also providing relief from constant eyestrain. Since many of us look at our mobile devices right before going to bed, these lenses also can reduce the amount of the blue light we see when we should be winding down. This will allow the activating nature of this light to be reduced right before we need to sleep. These lens coatings are available in almost all products, and are recommended especially for glasses that will be worn mainly for extended computer use. I have discussed these options with many patients, and I have had very positive feedback from people reporting less eye fatigue and more comfort while using the computer when wearing these lenses. During your next visit please let our doctors and opticians know if you have any questions regarding these lens options.....and for the last time, wear sunglasses outside because it is WAY WORSE to be outside without sunglasses on than to be staring at a computer all day!